U.S. patent application number 11/479523 was filed with the patent office on 2006-11-09 for flash toaster for reading several types of flash memory cards with or without a pc.
This patent application is currently assigned to OnSpec Electronic, Inc.. Invention is credited to Larry Lawson Jones, Sreenath Mambakkam, Arockiyaswamy Venkidu.
Application Number | 20060253636 11/479523 |
Document ID | / |
Family ID | 24446871 |
Filed Date | 2006-11-09 |
United States Patent
Application |
20060253636 |
Kind Code |
A1 |
Jones; Larry Lawson ; et
al. |
November 9, 2006 |
Flash toaster for reading several types of flash memory cards with
or without a PC
Abstract
A flash-memory-card reader reads and writes multiple types of
flash-memory cards, including CompactFlash, and the smaller
SmartMedia, MultiMediaCard, Secure Digital, and Memory Stick. A
converter chip converts the different card signals for transfer to
a host personal computer (PC). Serial-to-parallel data conversion
is performed for the smaller card formats with serial data
interfaces, but not for CompactFlash with a parallel-data
interface. A single slot has a 50-pin connector for CompactFlash
cards or passive adapters. The passive adapters have the
CompactFlash form factor and a smaller connector fitting smaller
flash cards. Passive adapters have no components but simply wire
the smaller connector to the CompactFlash connector. A pin mapping
allows card-type detection by sensing the LSB address pins of the
CompactFlash interface. A larger CompactFlash reader has multiple
slots for each card type. The reader is connected to the PC by a
cable, or located within the PC chassis in a drive bay. A
stand-alone reader copies images from the flash-memory card to a
removable disk media. Pressing a button initiates image
transfer.
Inventors: |
Jones; Larry Lawson; (Palo
Alto, CA) ; Mambakkam; Sreenath; (San Jose, CA)
; Venkidu; Arockiyaswamy; (Menlo Park, CA) |
Correspondence
Address: |
GREENBERG TRAURIG, LLP
1900 UNIVERSITY AVENUE
FIFTH FLOOR
EAST PALO ALTO
CA
94303
US
|
Assignee: |
OnSpec Electronic, Inc.
|
Family ID: |
24446871 |
Appl. No.: |
11/479523 |
Filed: |
June 30, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10167925 |
Jun 11, 2002 |
|
|
|
11479523 |
Jun 30, 2006 |
|
|
|
09610904 |
Jul 6, 2000 |
6438638 |
|
|
10167925 |
Jun 11, 2002 |
|
|
|
Current U.S.
Class: |
710/301 |
Current CPC
Class: |
G06F 3/0646 20130101;
G06K 7/0073 20130101; G06F 13/387 20130101; G06F 13/4027 20130101;
G06K 7/0052 20130101; G06K 19/07741 20130101; G06K 7/0013 20130101;
H05K 5/0282 20130101; G06F 13/385 20130101; G06K 7/0043 20130101;
G06F 13/38 20130101 |
Class at
Publication: |
710/301 |
International
Class: |
H05K 7/10 20060101
H05K007/10 |
Claims
1. A memory card reader, comprising: A first memory card slot
configured to receive a memory card of a first format; A second
memory card slot configured to receive a memory card of a second
format different from the first format; A first connector coupling
the first memory card slot to a converter; and A second connector
coupling the second memory card slot to the converter, wherein the
converter is to detect a memory card having been inserted into the
first or second memory card slot and to read data from the inserted
card.
2. The memory card reader of claim 1, wherein the converter is to
read data from the inserted card using a pin interface
corresponding to the respective format of the inserted card.
3. The memory card reader of claim 1, wherein the second format
comprises a smaller pin count relative to the first format.
4. The memory card reader of claim 3, wherein data is to be
transferred from the first memory card slot to the converter via a
serial transfer, and data is to be transferred from the second
memory card slot to the converter via a parallel transfer.
5. The memory card reader of claim 2, wherein the memory card
reader is external to the computer system.
6. The memory card reader of claim 2, wherein the memory card
reader is integrated in a computer system.
7. The memory card reader of claim 1, wherein each memory card slot
of the memory card reader corresponds to a separate format from a
group comprising of at least a CompactFlash (CF) format; a
MultiMediaCard or Secure Digital Card (MMC/SD) format; a SmartMedia
format; and a Memory Stick format.
8. The memory card reader of claim 3, further comprising a third
memory card slot to receive a memory card of a third format; and a
third connector coupling the third memory card slot to the
converter.
9. The memory card reader of claim 7, further comprising a fourth
memory card slot to receive a memory card of a fourth format; and a
fourth connector coupling the fourth memory card slot to the
converter, wherein each memory.
10. The memory card reader of claim 1, wherein the converter is to
transfer data from a memory card inserted in the first memory card
slot to a memory card inserted in the second memory card slot.
11. The memory card reader of claim 1, wherein each separate memory
card slot is identified as a separate media drive by an operating
system of a computer system coupled to the memory card reader.
12. The memory card reader of claim 1, wherein the memory card
reader is configured to be inserted in a device bay of a computer
system, the device bay is one of a group comprising of at least a
floppy disk drive bay, a CD-ROM drive device bay, a DVD device bay,
and a tape drive device bay.
13. The memory card reader of claim 2, further comprising a
removable storage device to receive a storage media having a
storage capacity greater than the first or second format, and the
converter to transfer data from a memory card inserted in the first
or second memory slot to the storage media inserted in the
removable storage device.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] Under 35 U.S.C. .sctn.120, this application is a
continuation application of U.S. Application Ser. No. 10/167,925,
which was filed on Jun. 11, 2002, which is a continuation
application of U.S. Application Ser. No. 09/610,904 which was filed
Jul. 6, 2000 and issued as U.S. Pat. No. 6,438,638 on Aug. 20,
2002, and is titled "Flashtoaster for Reading Several Types of
Flash Memory Cards With or Without a PC", the priority of which is
hereby claimed, and the entirety of which are incorporated herein
by reference, and all of which are assigned to the assignee of the
present invention.
FIELD OF THE INVENTION
[0002] This invention relates to flash-memory readers, and more
particularly for interfacing several different types of
flash-memory cards to a personal computer.
BACKGROUND OF THE INVENTION
[0003] Digital cameras have become one of the most popular of
electronic devices. In a recent year, more digital cameras were
sold than traditional film cameras. Images from digital cameras can
be downloaded and stored on personal computers. Digital pictures
can be converted to common formats such as JPEG and sent as e-mail
attachments or posted to virtual photo albums on the Internet.
Video as well as still images can be captured, depending on the
kind of digital camera.
[0004] Digital cameras typically capture images electronically and
ultimately store the images as bits (ones and zeros) on a
solid-state memory. Flash memory is the most common storage for
digital cameras. Flash memory contains one or more
electrically-erasable read-only-memory (EEPROM) integrated circuit
chips that allow reading, writing, and block erasing.
[0005] Early digital cameras required the user to download or
transfer the images from the flash memory within the digital camera
to a personal computer (PC). A standard serial cable was most
widely used. However, the limited transfer rate of the serial cable
and the large size of the digital images made such serial downloads
a patience-building experience. Serial downloads could easily take
half an hour for only a few dozen images.
[0006] Digital camera manufacturers solved this problem by placing
the flash memory chips on a small removable card. The flash-memory
card could then be removed from the digital camera, much as film is
removed from a standard camera. The flash-memory card could then be
inserted into an appropriate slot in a PC, and the image files
directly copied to the PC.
[0007] FIG. 1A shows a flash memory card and adapter for
transferring images from a digital camera to a PC. A user takes
pictures with digital camera 14 that are stored in image files on
flash memory chip(s). The flash memory chip is contained in
CompactFlash card 16, which can be removed from digital camera 14
by pressing a card-eject button. Thus CompactFlash card 16 contains
the image files.
[0008] While some smaller hand-held computers or
personal-digital-assistants (PDA) have slots that receive
CompactFlash cards, most PC's do not. Laptop or notebook PC's have
PC card (earlier known as PCMCIA, Personal Computer Memory Card
International Association) slots that can receive PCMCIA cards.
Many functions have been placed on PCMCIA cards, such as modems,
Ethernet, flash memory, encryption keys, and even miniature hard
drives.
[0009] CF-to-PCMCIA adapter 10 is a passive adapter that contains
an opening that receives CompactFlash card 16. FIG. 1B shows
CF-to-PCMCIA adapter 10 with CompactFlash card 16 inserted. Such
CF-to-PCMCIA adapters 10 sell for as little as $5-10. CompactFlash
is a trademark of SanDisk Corp. of Sunnyvale, Calif.
[0010] FIG. 1C shows a PC connected to a PCMCIA reader. Most laptop
and notebook PC's contain one or two PCMCIA slots 22 that
CF-to-PCMCIA adapter 10 can fit into. Then the user merely has to
copy the image files from CompactFlash card 16 to the hard disk of
PC 20. Since high-speed parallel buses are used, transfer is rapid,
about the same speed as accessing the hard disk. Thus a half-hour
serial-cable transfer can be reduced to less than a minute with the
$5 CF-to-PCMCIA adapter.
[0011] Desktop PC's usually do not have PCMCIA slots. Then PCMCIA
reader 12 can be used. PCMCIA reader 12 accepts CF-to-PCMCIA
adapter 10 and connects to PC 20 through a parallel or high-speed
Universal Serial Bus (USB) cable.
Multiple Flash-Card Formats
[0012] Although the CompactFlash card format is relatively small,
being not much more than an inch square, other smaller cards have
recently emerged. FIG. 2A illustrates various formats of
flash-memory cards used with digital cameras. Many digital cameras
still, use CompactFlash card 16, which can be inserted into
CF-to-PCMCIA adapter 10 for transfer to a PC. Other smaller,
thinner formats have emerged and are used with some manufacturer's
digital cameras. For example, SmartMedia card 24 is less than half,
an inch long, yet has enough flash memory capacity for dozens of
images. SmartMedia-to-PCMCIA adapter 10' is available commercially
for about $60. The higher cost is believed to be due to a converter
chip within adapter 10'. Also, different adapters 10' are required
for different memory capacities of SmartMedia card 24. SmartMedia
is a trademark of the SSFDC Forum of Tokyo, Japan.
[0013] Other kinds of flash-memory cards that are being championed
by different manufacturers include MultiMediaCard (MMC) 28 and the
related Secure Digital Card (SD) 26. MMC is a trademark of SanDisk
Corp. of Sunnyvale, California while SD is controlled by the SD
Group that includes Matsushita Electric Industrial Co., SanDisk
Corporation, Toshiba Corp. Another emerging form factor from SONY
is Memory Stick 18. Memory Stick has a PCMCIA/Floppy adapter while
MMC has a floppy adapter.
[0014] The different physical shapes and pin arrangements of cards
24, 26, 28 and Memory Stick 18 prevent their use in CF-to-PCMCIA
adapter 10. Indeed, most of these cards 24, 26, 28 have less than a
dozen pins, while CompactFlash card 16 has a larger 50-pin
interface. Furthermore, serial data interfaces are used in the
smaller cards 24, 26, 28 while a parallel data bus is used with
CompactFlash card 16.
[0015] FIG. 2B shows a Memory Stick-to-PCMCIA adapter, using an
active converter chip. Memory Stick 18 fits into an opening in
Memory Stick-to-PCMCIA adapter 15, allowing adapter 15 and the
Memory Stick to be plugged into a standard PCMCIA slot on a PC.
However, adapter 15 has an integrated circuit (IC) converter chip
11 within it. Converter chip 11 may be needed to convert the serial
data format of Memory Stick 18 to the parallel data format of a
68-pin PCMCIA slot. Inclusion of converter chip 11 in adapter 15
significantly increases the cost and complexity of adapter 15
compared to CF-to-PCMCIA adapter 10 which is a passive adapter
without a converter chip.
[0016] While the advances in flash-memory card technology are
useful, the many different cards formats present a confusing array
of interface requirements to a PC. Different adapters are needed
for each of the card formats. PCMCIA card reader 12 can be replaced
with other format readers, such as a SmartMedia Card reader, and
even some multi-standard readers are available, such as a universal
reader from Lexar Media that reads CompactFlash or SmartMedia in
addition to PCMCIA.
[0017] What is desired is a universal adapter for flash-memory
cards of several different formats. An adapter that accepts
SmartMedia, MultiMediaCard, Secure Digital, and Memory Stick cards
is desired. A flash-card reader with a single slot that accepts any
format card using the adapter is desired. Special detection logic
on the flash reader is desired to distinguish between the many
flash-card formats is desirable. A low-cost passive adapter is
desired that does not need an expensive converter chip. A
multi-format reader is desired for a PC. A stand-alone flash reader
is desired that can copy image files from flash cards without a PC
is also desired.
SUMMARY OF THE INVENTION
[0018] A single-slot multi-flash-card reader has a personal
computer interface for transferring data to a personal computer. A
converter means is coupled to the personal computer interface. It
converts multiple flash-card interfaces to a format used by the
personal computer interface. The multiple flash-card interfaces
include a CompactFlash interface and smaller interfaces having
fewer pins than the CompactFlash interface.
[0019] A CompactFlash connector is coupled to the converter means.
It receives a CompactFlash card through a single slot in the
single-slot multi-flash-card reader. The CompactFlash connector
makes electrical connection with the CompactFlash card for signals
in the CompactFlash interface.
[0020] An adapter has a physical shape to removably insert into the
CompactFlash connector. The adapter has a mating CompactFlash
connector that fits the CompactFlash connector. The adapter also
has a smaller connector. The smaller connector fits to other
flash-memory cards having the smaller interfaces.
[0021] A wiring means in the adapter connects between the smaller
connector and the mating CompactFlash connector. It directly
connects signals from the smaller connector in the smaller
interface with signals in the mating CompactFlash connector. Thus
the adapter allows the other flash-memory cards having the smaller
interfaces to fit into the CompactFlash connector through the
single slot to be read by the converter means.
[0022] In further aspects the wiring means connects card select
signals from all of the smaller interfaces to card select signals
in the CompactFlash connector. The converter means includes a
card-detect means that is coupled to sense the card select signals.
It detects presence of a flash-memory card inserted into the
CompactFlash connector. Thus the converter means detects presence
of CompactFlash and the other flash-memory cards having the smaller
interfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1A shows a flash memory card and adapter for
transferring images from a digital camera to a PC.
[0024] FIG. 1B shows CF-to-PCMCIA adapter 10. with CompactFlash
card 16 inserted. FIG. 1C shows a PC connected to a PCMCIA
reader.
[0025] FIG. 2A illustrates various formats of flash-memory cards
used with digital cameras. FIG. 2B shows a Memory Stick-to-PCMCIA
adapter using an active converter chip. FIG. 3A shows a universal
CompactFlash adapter that accepts SmartMedia, MultiMediaCard,
Secure Digital, and Memory Stick flash-memory cards.
[0026] FIG. 3B shows a CompactFlash reader that reads SmartMedia,
MultiMediaCard, Secure Digital, and Memory Stick flash-memory cards
through passive adapters to the CompactFlash form factor.
[0027] FIGS. 4A-E show card-type detection using the A1, A0 pins of
the CompactFlash reader interface.
[0028] FIG. 5 is a table of pin mappings for the SmartMedia,
MMC/SD, and Memory Stick to CompactFlash adapters.
[0029] FIG. 6 is a diagram of a multi-slot embodiment of the
flash-card reader. FIG. 7 shows a flash memory reader within a
PC.
[0030] FIG. 8 shows a PC chassis with a flash-card reader in one of
the drive bays. FIG. 9 is a diagram of a stand-alone FlashToaster
that accepts several formats of flash-memory cards and can copy
images to a removable disk without being connected to a host
PC.
[0031] FIG. 10 is a diagram of the converter chip for the
flash-memory reader.
DETAILED DESCRIPTION
[0032] The present invention relates to an improvement in
flash-memory card readers. The following description is presented
to enable one of ordinary skill in the art to make and use the
invention as provided in the context of a particular application
and its requirements. Various modifications to the preferred
embodiment will be apparent to those with skill in the art, and the
general principles defined herein may be applied to other
embodiments. Therefore, the present invention is not intended to be
limited to the particular embodiments shown and described, but is
to be accorded the widest scope consistent with the principles and
novel features herein disclosed.
[0033] The inventors have realized that a universal adapter can be
constructed using the CompactFlash card form factor. A reader that
reads CompactFlash cards can then read any of the other
flash-memory cards that plug into the CompactFlash adapter. The
adapters are simple, inexpensive passive adapters without a
conversion chip.
[0034] The inventors have found a pin mapping from the smaller
flash-card formats to CompactFlash that allows for easy detection
of the type of flash-memory card inserted into the adapter.
Detection of the type of flash-memory card is thus performed
automatically by electronic detection by the CompactFlash reader.
The CompactFlash reader is modified to perform this card-type
detection. Signal conversion such as serial-to-parallel is
performed by the CompactFlash reader rather than by the adapter.
Adapter costs are reduced while CompactFlash reader cost is
increased only slightly. The CompactFlash reader can use a single
CompactFlash slot to read multiple flash-card types, including
SmartMedia, MultiMediaCard, Secure Digital, Memory Stick, and
CompactFlash.
[0035] In another embodiment, the CompactFlash reader is somewhat
larger, and has multiple slots. The adapter is not needed in this
embodiment. Instead, a slot is provided for each of the
flash-memory card formats--SmartMedia, MultiMediaCard, Secure
Digital, Memory Stick, and CompactFlash. A PCMCIA can also be
added. This CompactFlash reader can be connected to the PC by a USB
cable, or it can be located within the PC chassis.
[0036] In a third embodiment, the CompactFlash reader is a
stand-alone device that can operate without a PC. A removable disk
media such as a R/W CD-ROM is included. Images from the
flash-memory card are copied to the removable disk media by the
CompactFlash reader. A simple interface is used, such as having the
user press a button to initiate image transfer.
Universal, Passive Adapters--FIGS. 3A-B
[0037] FIG. 3A shows a universal CompactFlash adapter that accepts
SmartMedia, MultiMediaCard, Secure Digital, and Memory Stick
flash-memory cards. Digital camera 14 stores images on flash memory
that is in one of several card types. CompactFlash card 16 uses a
50-pin connector and transfers image data in a 16-bit parallel
format.
[0038] SmartMedia card 24 is smaller flash-memory card with a
22-pin interface and transfers data in an 8-bit parallel format.
SmartMedia adapter 30 converts the 22-pin SmartMedia interface to
fit within the 50-pin CompactFlash interface. When SmartMedia card
24 is plugged into SmartMedia adapter 30, both can be plugged into
a CompactFlash slot on a CompactFlash reader. Of course, ordinary
CompactFlash readers will not be able to read SmartMedia card 24
since special signal conversion is required by the CompactFlash
reader.
[0039] MultiMediaCard 28 and Secure Digital card 26 are
flash-memory cards with similar 9-pin interfaces. Serial data
transfer is used through a single Data I/O pin. MMC/SD adapter 32
has an opening with a 9-pin connector to receive either
MultiMediaCard 28 or Secure Digital card 26. Once MultiMediaCard 28
or Secure Digital card 26 is inserted into MMC/SD adapter 32, then
MMC/SD adapter 212 can be inserted into a CompactFlash slot on a
special CompactFlash reader. The CompactFlash reader then detects
the card type and performs serial-to-parallel conversion.
[0040] Memory Stick 18 is also a flash-memory card with a 9-pin,
serial-data interface, but is narrower and longer than
MultiMediaCard 28 or Secure Digital card 26. Memory Stick adapter
34 has an opening with a 10-pin connector to receive Memory Stick
18. Once Memory Stick 18 is inserted, Memory Stick adapter 32 can
itself be inserted into a CompactFlash slot on a special
CompactFlash reader. The CompactFlash reader then detects the card
type and performs serial-to-parallel conversion.
[0041] FIG. 3B shows a CompactFlash reader that reads SmartMedia,
MultiMediaCard, Secure Digital, and Memory Stick flash-memory cards
through passive adapters to the CompactFlash form factor.
CompactFlash reader 42 has an opening or slot with 50-pin connector
44 that accepts CompactFlash card 16. Controller chip 40 performs
handshaking with CompactFlash card 16 and performs data transfer.
CompactFlash reader 42 also connects to a PC over USB connector 46.
Controller chip 40 also controls the USB interface to the host PC,
allowing image files to be transferred to the PC from CompactFlash
card 16.
[0042] Other kinds of flash-memory cards can also be read by
CompactFlash reader 42. For example, adapter 34 allows Memory Stick
18 to be read. Memory Stick adapter 34 has an opening that Memory
Stick 18 fits into, while Memory Stick adapter 34 itself fits into
50-pin connector 44, since adapter 34 has the same form factor as a
CompactFlash card.
[0043] SmartMedia card 24 can also be read by CompactFlash reader
42, using SmartMedia adapter 30. Likewise, MultiMediaCard 28 or
Secure Digital card 28 can be read using MMC/SD adapter 32.
[0044] Adapters 30, 32, 34 are passive adapters that only connect
pins from the smaller flash-memory cards to the 50-pin CompactFlash
connector. An active converter chip is not required, greatly
reducing cost and complexity.
Detection of Card Type--FIGS. 4A-E.
[0045] FIGS. 4A-E detail detection of the type of flash-memory card
by the CompactFlash reader. Since the same CompactFlash slot is
used for many kinds of flash-memory cards, a detection method is
useful so that the user doesn't have to explicitly indicate what
type of flash-memory card is inserted into the CompactFlash
reader.
[0046] The inventors have carefully examined the pins of the
interfaces to the various flash-memory cards and have discovered
that type-detection can be performed by examining two address pins.
Address pins A0 and A1 are the least-significant-bits (LSB) of the
address of the 50-pin CompactFlash interface. These pins are
normally inputs to the CompactFlash card and thus are driven by the
CompactFlash reader. When the reader does not drive A0, A1 to the
inserted CompactFlash card, the A0, A1 pins float or are pulled
high by pullup resistors.
[0047] Address pins are not present on the other kinds of
flash-memory cards. Instead, the address and data are multiplexed.
For MMC/SD and Memory Stick, the address is sent serially. Using
the adapters, pins from the other flash-memory cards can be
connected to the CompactFlash pins. Pins A0 and A1 are used to
detect the type of card. For SmartMedia, the addresses are sent by
using a special control sequence followed by 3 or 4 bytes of
starting address.
[0048] In FIG. 4A, the A1, A0 pins of the CompactFlash reader
interface are highlighted. Converter chip 40 in the CompactFlash
reader normally drives all 11 address pins in the CompactFlash
interface when reading a CompactFlash card plugged into connector
44. The A0 pin from the CompactFlash card plugs into connector cup
56, while the A1 pin from the CompactFlash card plugs into
connector cup 58 of 50-pin connector 44.
[0049] Card-type detector 50 has two pullup resistors added to
lines A0, A1. Resistor 52 pulls line A0 high to power (Vcc) when
neither converter chip 40 nor a card plugged into connector 44
drives line A0. Likewise, resistor 54 pulls line A1 high when line
A1 is not being actively driven. During detection mode, converter
chip 40 is programmed to not drive lines A0, A1 and instead use
then as inputs to the detector logic.
[0050] In FIG. 4B, a CompactFlash card is inserted into the
connector for card-type detection. CompactFlash card 16 is plugged
into connector 44. Since A0 and A1 are inputs to CompactFlash card
16, they are not driven by CompactFlash card 16. During detection
mode, converter chip 40 also does not drive pins A0, A1. Thus lines
A0, A1 are left floating and are each pulled high by resistors 52,
54.
[0051] Detection logic in converter chip 40 reads card-select pins
CD0, CD1 to detect the presence of a flash-memory card. When a new
card is present, detection logic then reads pins A0, A1 as inputs.
Both inputs are high. The detection logic in converter chip 40
recognizes the LH state of A0, A1 as indicating that a CompactFlash
card is plugged into connector 44. Converter chip 40 then exits
detection mode and configures its interface to connector 44 for the
50-pin CompactFlash interface as shown later in FIG. 5.
[0052] In FIG. 4C, a MultiMediaCard or Secure Digital card is
inserted into the connector for card-type detection. MMC/SD card 28
(not shown) is plugged into MMC/SD adapter 32 which is plugged into
connector 44.
[0053] Converter chip 40 does not drive pins A1, A0 during
detection mode. Thus pin A1 floats and is pulled high by resistor
54. The A0 pin is driven low by the MMC card.
[0054] Detection logic in converter chip 40 reads card-select pins
CD0, CD1 to detect the presence of a flash-memory card. When a new
card is present, detection logic then reads pins A0, A1 as inputs.
While A0 is low, A1 is high. The detection logic in converter chip
40 recognizes the HL state of A0, A1 as indicating that a MMC or SD
card is plugged into connector 44. Converter chip 40 then exits
detection mode and configures its interface to connector 44 for the
9-pin MMC/SD interface as shown later in FIG. 5.
[0055] In FIG. 4D, a SmartMedia card is inserted into the connector
for card-type detection. SmartMedia card 24 (not shown) is plugged
into SmartMedia adapter 30 which is plugged into connector 44. The
adapter 30 does not connect pins A0, Al from the CompactFlash
interface to any pins on the SmartMedia card. Adapter 30 internally
connects pin A1 from the CompactFlash interface to the ground pin
on the CompactFlash interface.
[0056] The SmartMedia card does not drive either pin A1, A0,
although adapter 30 drives pin A1 low. Likewise, converter chip 40
does not drive pins A1, A0 during detection mode. Pin A0 floats and
is pulled high by resistor 52.
[0057] Detection logic in converter chip 40 reads card-select pins
CD0, CD1 to detect the presence of a flash-memory card. When anew
card is present, detection logic then reads pins A0, A1 as inputs.
While A0 is high, A1 is low. The detection logic in converter chip
40 recognizes the HL state of A0, A1 as indicating that a
SmartMedia card is plugged into connector 44. Converter chip 40
then exits detection mode and configures its interface to connector
44 for the 22-pin SmartMedia interface as shown later in FIG.
5.
[0058] In FIG. 4E, a Memory Stick card is inserted into the
connector for card-type detection. Memory Stick card 18 (not shown)
is plugged into Memory Stick adapter 34 which is plugged into
connector 44.
[0059] Detection logic in converter chip 40 reads card-select pins
CD0, CD1 to detect the presence of a flash-memory card. When a new
card is present, detection logic then reads pins A0, A1 as inputs.
Both pins A0, A1 are low. The detection logic in converter chip 40
recognizes the LL state of A0, A1 as indicating that a Memory Stick
card is plugged into connector 44.
Pin Mapping--FIG. 5
[0060] FIG. 5 is a table of pin mappings for the SmartMedia,
MMC/SD, and Memory Stick to CompactFlash adapters. The pin numbers
for the smaller interfaces for SmartMedia, MMC/SD, and Memory Stick
are not shown but can be in any order or designation. The adapter
connects the proper pin on the smaller interface to the
CompactFlash pin number shown in FIG. 5. Simple wiring such as
individual wires, flat cables, printed-circuit board (PCB), or
wiring traces can be used.
[0061] The ground pins on the smaller interfaces are connected to
CompactFlash pins 1 and 50. Power pins are connected to
CompactFlash pins 13, 38. Pins 25, 26 are the card detect signals
for CompactFlash, which the adapters connect to the card-detect
signals on all smaller interfaces.
[0062] The CompactFlash connectors use pins 2-6, 21-23, 27-31, and
47-49 for the 16-bit parallel data bus to the CompactFlash card.
Pins 8,10-12, and 14-20 form a separate 11-bit address bus. The
separate data and address buses provide for rapid random addressing
of CompactFlash cards. Other control signals include pins 6, 32
chip enables, pin 9 output enable, pin 36 write enable, interrupt
pin 37, reset pin 41, and register REG pin 44. REG pin 44 is the
Attribute Memory Select, defined based on the CF mode of operation,
i.e. PCMCIA I/O mode, IDE or PCMCIA Memory Mode. Several pins in
the 50-pin interface are not connected.
[0063] The smaller SmartMedia interface also has a parallel data
bus of 8 bits. These are mapped to pins 2-6, and 21-23 of the
CompactFlash interface to match the CompactFlash D0:7 signals.
While no separate address bus is provided, address and data are
multiplexed. Control signals for latch enables, write enable and
protect, output enable, and ready handshake are among the control
signals. Output enable -OE and write enable -WE are mapped to the
same function pins 9, 36 of the CompactFlash interface. The total
number of pins in the SmartMedia interface is 22.
[0064] The Memory Stick and MMC/SD flash-memory-card interfaces are
smaller still, since parallel data or address busses are not
present. Instead, serial data transfers occur through serial data
pin DIO, which is mapped to pin 19 (A1). Data is clocked in
synchronization to clock SCLK on pin 18. A command signal CMD or BS
occupies pin 20 (A0). The MMC/SD and Memory Stick interfaces
require only 6 pins plus power and ground.
[0065] Detection logic in converter chip 40 reads card-select pins
CD0, CD1 to detect the presence of a flash-memory card. When a new
card is present, detection logic then reads pins A0, A1 as inputs
to determine the card type. The pullup resistors of FIG. 4A
together with wiring inside the adapter and the card's behavior
determines whether A0, A1 are pulled low by the adapter or pulled
high by the pullup resistors.
Multi-Slot Multi-Flash-Card Reader--FIG. 6
[0066] FIG. 6 is a diagram of a multi-slot embodiment of the
flash-card reader. While the single-slot embodiment of FIG. 3B
results in the smallest physical design, somewhat larger flash-card
readers can be made that have separate slots for each type of
flash-memory card, rather than a single slot. This negates the need
for the adapters.
[0067] Four connectors are provided in flash reader 42: a 50-pin
CompactFlash connector 62 that fits CompactFlash card 16, a 9 pin
MMC/SD connector 64 that fits MultiMediaCard 28 or a Secure Digital
card, a 22 pin SmartMedia connector 66 that fits SmartMedia card
24, and a 10-pin Memory Stick connector 68 that fits Memory Stick
18.
[0068] Each of the four connectors 62, 64, 66, 68 route their
signals to converter chip 40. Converter chip 40 detects when a
flash-memory card has been inserted into one of the connectors 62,
64, 66, 68 and configures itself to read files from the inserted
card using the pin interface of FIG. 5 corresponding to the card
type.
[0069] Converter chip 40 executes various routines to perform
handshaking with the flash-memory cards and accept data, either
serially or in parallel. The data is buffered and then sent to the
host PC 20 through USB connector 46. Converter chip 40 generates
the appropriate USB-interface signals to transfer the data to host
PC 20.
[0070] Having separate connectors 62, 64, 66, 68 with separate
slots in flash reader 42 allows for card-to-card transfers. For
example, images or other files from Memory Stick 18 could be
transferred to CompactFlash card 16 by converter chip 40 reading
serial data from Memory Stick inserted into connector 68,
converting to parallel, and writing to connector 62 and
CompactFlash card 16. Each of the flash-memory cards in connectors
62, 64, 66, 68 can be assigned a different drive letter by the
operating system, such as e:, f:, g:, and h:.
[0071] In this embodiment, flash reader 42 is contained in an
external housing that connects to host PC 20 through a USB cable.
Of course, other cables and interfaces such as IEEE 1394 FireWire
may be substituted.
Flash Reader Within PC--FIG. 7
[0072] FIG. 7 shows a flash-memory reader within a PC. Four slots
and four connectors are provided in flash reader 42. A 50-pin
CompactFlash connector 62 fits CompactFlash card 16, a 9-pin MMC/SD
connector 64 fits MultiMediaCard 28 or a Secure Digital card, a
22-pin SmartMedia connector 66 fits SmartMedia card 24, and a
10-pin Memory Stick connector 68 fits Memory Stick 18.
[0073] Each of the four connectors 62, 64, 66, 68 route their
signals to converter chip 40. Converter chip 40 detects when a
flash-memory card has been inserted into one of the connectors 62,
64, 66, 68 and configures itself to read files from the inserted
card using the pin interface of FIG. 5 corresponding to the card
type. Each of the flash-memory cards in connectors 62, 64, 66, 68
can be assigned a different drive letter by the operating system,
such as e:, f:, g:, and h:.
[0074] Converter chip 40 executes various routines to perform
handshaking with the flash-memory cards and accept data, either
serially or in parallel. The data is buffered and then sent to the
CPU 21 in PC 20 through an internal USB bus. Converter chip 40
generates the appropriate USB-interface signals to transfer the
data to CPU 21.
[0075] FIG. 8 shows a PC chassis with a flash-card reader in one of
the drive bays. PC 20 is enclosed by a chassis or case that has
several drive bays allowing the user or manufacturer to insert
peripherals such as hard and floppy disk drives, CD-ROM and DVD
drives, and tape drives. HDD bay 72 contains a hard-disk drive,
while FDD bay 74 contains a floppy disk drive. These are connected
by cables to cards inserted into a USB, ATA, or other expansion bus
connectors on the motherboard.
[0076] Flash reader 42 is inserted into one of the drive bays. The
four slots face forward, allowing the user to insert flash-memory
cards into flash reader 42 much as a floppy disk is inserted into
the floppy-disk drive in FDD bay 74.
[0077] Flash reader 42 can be installed by the user from a kit
purchased at a store, or it can be pre-installed by an
original-equipment manufacturer (OEM) or retailer. The user can
easily transfer digital images from a digital camera, regardless of
the type of flash-card used by the camera, due to the many
different formats of flash-memory cards read by flash reader
42.
FlashToaster--FIG. 9
[0078] FIG. 9 is a diagram of a stand-alone FlashToaster that
accepts several formats of flash-memory cards and can copy images
to a removable disk without being connected to a host PC. Digital
photographers may not always have their PC's nearby. While extra
flash-memory cards can be purchased and swapped in the digital
camera, these flash-memory cards are somewhat expensive, especially
when many high resolution images are captured. Especially during a
long trip away from the PC, the user may be limited by the capacity
of the flash-memory cards.
[0079] FlashToaster 80 has four slots and four connectors are
provided in FlashToaster 80. A 50-pin CompactFlash connector 62
fits CompactFlash card 16, a 9-pin MMC/SD connector 64 fits
MultiMediaCard 28 or a Secure Digital card, a 22-pin SmartMedia
connector 66 fits SmartMedia card 24, and a 10-pin Memory Stick
connector 68 fits Memory Stick 18.
[0080] Each of the four connectors 62, 64, 66, 68 route their
signals to converter chip 40. Converter chip 40 detects when a
flash-memory card has been inserted into one of the connectors 62,
64, 68 by sensing card select lines CD0, CD1 and configures itself
to read files from the inserted card using the pin interface of
FIG. 5 corresponding to the card type.
[0081] Converter chip 40 executes various routines to perform
handshaking with the flash-memory cards and accept data, either
serially or in parallel. The data is buffered and then sent either
to host PC 20 through USB connector 46 or to removable mass storage
70. Converter chip 40 generates the appropriate USB-interface
signals to transfer the data to host PC 20. Converter chip 40 also
generates the control signals for removable mass storage 70,
allowing the image data read from the flash-memory card to be
written to removable disk 76. Removable disk 76 could be a standard
or a high-density floppy diskette, a tape drive, a writeable CD-R/W
disk, or other proprietary media such as LS120 by Imation of
Oakdale, Minnesota, or ZIP drives by lomega Corp. of Roy, UT.
[0082] Each of the flash-memory cards in connectors 62, 64, 66, 68
can be assigned a different drive letter by the operating system,
such as e:, f:, g:, and h:. Removable mass storage 70 can also be
assigned a drive letter.
[0083] When FlashToaster 80 is not attached to host PC 20, image
files may still be copied to removable mass storage 70.
FlashToaster 80 may be carried along on a trip by the user,
allowing the user to download image files to removable disk 76.
Since removable disk 76 ordinarily has a much higher capacity than
the flash-memory cards, many pictures may be captured when no
access to host PC 20 is available. FlashToaster 80 can be provided
with battery power or with its own AC converter.
[0084] FlashToaster 80 is provided with a simple user interface,
including light-emitting diode LED 78 and button 79. When the user
inserts a flash-memory card into one of connectors 62, 64, 66, 68,
and removable disk 7,6 is inserted into removable mass storage 70,
the user presses button 79. This activates controller chip 40,
which determines which of connectors 62, 64, 66, 68 has a memory
card inserted, and copies the image files to removable mass storage
70. LED 78 can be programmed to blink during the copying process,
and remain lit when the copying is complete, or vice-versa. This
provides a simple visual indication to the user of the copying
progress. Errors can be indicated With additional LED indicator
lamps, or other blinking arrangements or colors.
Converter Chip--FIG. 10
[0085] FIG. 10 is a diagram of the converter chip for the
flash-memory reader. Converter chip 40 can be implemented as a
commercially-available micro-controller chip that is programmed to
read and write I/O pins that are connected to the flash-memory-card
connectors and USB interface. Several different control and
transfer routines are written and programmed into RAM/ROM 94. CPU
92 then executes these routines. A high-level scanning routine can
sense when a flash-memory card is inserted. CPU 92 can then begin
execution of another routine specific to that type of flash-memory
card. Transfer and handshake sub-routines can then be called.
[0086] General purpose input-output GPIO 99 provides registers or
1/0 ports that drive external I/O pins of converter chip 40, or
read the logic-levels or voltages on input pins to converter chip
40. CPU 92 can read registers in GPIO 99 that are written by
control signals that are coupled to I/O pins of converter chip 40
from connectors 62, 64, 66, 68. Control signals to the flash-memory
cards can be switched high or low by writing a 1 or a 0 to a
register for that control signal in GPIO 99.
[0087] Timers 96 are useful for asserting control signals for a
required amount of time. For example, a control signal may need to
be asserted for a specified number of microseconds. CPU 92 can
write a 1 to a register in GPIO 99 and start a timer in timers 96.
Timer 6 can send an interrupt to CPU 96 when the specified time has
elapsed, or CPU 92 can continuously or periodically poll timers 96
to determine when the specified time has elapsed. Then CPU 92 can
write a 0 to the register in GPIO 99, causing the control signal to
transition from 1 to 0.
[0088] Shifter 98 is connected to the data and clock signals from
connectors 64, 68. When data is read from the flash-memory card, a
clock is pulsed to synchronize the data transfer. Shifter 98 clocks
in one bit (serial) or word (parallel) of data for each clock
pulse. A cyclical-redundancy-check (CRC) can be performed on the
data to detect errors. CPU 92 can request re-transmission of data
from the flash-memory card when an error is detected.
[0089] Data read by shifter 98 can be sent over internal bus 90 to
be stored in a buffer in RAM/ROM 94. Later, CPU 92 can execute a
routine to transfer this data from RAM/ROM 94 to USB interface 100.
USB interface 100 then transmits the data over an external USB link
to a host PC. When a removable mass storage is present, some of the
I/O pins from GPIO 99 can connect to the removable mass storage, or
a separate disk controller can be included on controller chip
40.
ADVANTAGES OF THE INVENTION
[0090] A universal adapter for flash-memory cards accepts cards of
several different formats. The adapter accepts SmartMedia,
MultiMediaCard, Secure Digital, and Memory Stick cards. The
flash-card reader with a single slot accepts any format card using
the adapter. Special detection logic on the flash reader
distinguishes between the many flash-card formats. The low-cost
passive adapter does not need an expensive converter chip. A
multi-format reader is ideal for use with a PC. However, a
stand-alone flash reader can copy image files from flash cards
without a PC. Additionally, preparation of media for use in devices
(format and erase operations) can be done using this reader.
[0091] A universal adapter is constructed using the CompactFlash
card form factor. A reader that reads CompactFlash cards can then
read any of the other flash-memory cards that plug into the
CompactFlash adapter. The adapters are simple, inexpensive passive
adapters without a conversion chip.
[0092] The disclosed pin mapping from the smaller flash-card
formats to CompactFlash allows for easy detection of the type of
flash-memory card inserted into the adapter. Detection of the type
of flash-memory card is thus performed automatically by electronic
detection by the CompactFlash reader. The CompactFlash reader is
modified to perform this card-type detection. Signal conversion
such as serial-to-parallel is performed by the CompactFlash reader
rather than by the adapter. Adapter costs are reduced while
CompactFlash reader cost is increased only slightly. The
CompactFlash reader can use a single CompactFlash slot to read
multiple flash-card types, including SmartMedia, MultiMediaCard,
Secure Digital, Memory Stick, and CompactFlash.
ALTERNATE EMBODIMENTS
[0093] Several other embodiments are contemplated by the inventors.
Different flash-card formats can be supported such as Smart Cards,
and more or less than the four slots shown in the multi-card flash
reader can be included. Other adapters can be used for newer flash
formats for the single-slot CompactFlash reader. Any device that
needs Control Bus, Clock, Data Bus and Address Bus can be designed
to fit into this slot. Examples of such devices include (but are
not limited to) DSL Modems, Fingerprint security devices, Miniature
Hard disks, etc.
[0094] While the invention has been described as connecting to a
personal computer PC host, the host may also be an Apple computer
such as the iMAC or G3. The host may also be a SUN computer, or any
host computer using USB or IDE interfaces. The invention can also
apply to Personal Digital Assistants (PDAs) such as by Palm
Computer or other handheld appliances such as a Cell phone with USB
capability.
[0095] The term "CompactFlash reader" has been used for simplicity,
since digital images are often read from the flash-memory card and
then written to the PC. However, the CompactFlash reader is capable
of reading files from the PC or from another flash-memory card and
writing the file to the flash-memory card. Thus the CompactFlash
reader is really a reader/writer.
[0096] In another embodiment, the CompactFlash reader is somewhat
larger, and has multiple slots. The adapter is not needed in this
embodiment. Instead, a slot is provided for each of the
flash-memory card formats--SmartMedia, MultiMediaCard, Secure
Digital, Memory Stick, and CompactFlash. A PCMCIA slot can also be
added. This CompactFlash reader can be connected to the PC by a USB
cable, or it can be located within the PC chassis.
[0097] In a third embodiment, the CompactFlash reader is a
stand-alone device that can operate without a PC. A removable disk
media such as a R/W CD-ROM is included. Images from the
flash-memory card are copied to the removable disk media by the
CompactFlash reader. A simple interface is used, such as having the
user presses a button to initiate image transfer.
[0098] The foregoing description of the embodiments of the
invention has been presented for the purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form disclosed. Many modifications and
variations are possible in light of the above teaching. It is
intended that the scope of the invention be limited not by this
detailed description, but rather by the claims appended hereto.
* * * * *