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CompactFlash bus

pinout

Developed by SanDisk. Is compatible with PC-Card ATA with a simple passive adapter.

 50 pin CompacFlash female
50 pin CompacFlash female connector  at the controller

Shown looking into card

Function   Function
MemI/OTrue IDE
Mode 4
 Pin MemI/OTrue IDE
Mode 4
GND---126-->!CD1
D03<->227<->D11
D04<->328<->D12
D05<->429<->D13
D06<->530<->D14
D07<->631<->D15
!CE1!CS0-->732<--!CE2!CS1
A10L-->833-->!VS1
!OE!ATA SEL-->934<--NU!IORD
A09L-->1035<--NU!IOWR
A08L-->1136<--!WE
A07L-->1237-->RDY/BSYIREQINTRQ
VCC---1338---VCC
A06L-->1439<--!CSEL
A05L-->1540-->!VS2
A04L-->1641<--RESET!RESET
A03L-->1742-->!WAITIORDY
A02-->1843-->NU!INPACKNC
A01-->1944<--!REGH
A00-->2045<->BVD2(H)!SPKR!DASP
D00<->2146<->BVD1(H)!STSCHG!PDIAG
D01<->2247<->D08
D02<->2348<->D09
WP!IOIS16!IOCS16-->2449<->D10
!CD2<--2550---GND
Essential for
minimal
8-bit interface.
Essential for
16-bit interface.

Connector

Pin pitch is 0.05". So it is best suited to surface mount. It is more convenient to lay out PCB tracks so that they approach from both edges instead of interleaving them as is usually done for ATA/IDE connectors.

In the UK, CPC sell CF headers, part ref CN5037.

See http://www.compactflash.org/ for the definitive specification.


Notes

CF combines features from ISA bus, 16-bit PCMCIA, and ATA/IDE buses. It can appear as I/O mapped, memory mapped, or as an IDE device. The IDE mode is always 16-bit, but I/O and memory modes can present data as 8 or 16-bits. These features make it the most flexible choice, allowing it to be used by devices other than the PC - such as 8-bit processors in consumer electronics.

The memory-mapped mode occupies 1K of address space, the top half containing the selected page of data.

  • You can access all data on the card, through 8 or 16 bit data bus.
  • L = Low logic
  • H = High logic
  • NC = No Connection
  • NU = Not Used
  • D08-D15 required only for 16 bit access and not required when installed in 8-bit systems.

1. Devices should allow for 3-state signals not to consume current.
2. Should be grounded by the host.
3. Should be tied to VCC by the host.
4. Optional for CF+ Cards, required for CompactFlash Storage Cards.

* indicates active low signal

  
GNDGround reference voltage.
VCCPower rail, usually 3V3, but can be 5V. The Compact Flash FAQ says:

"CompactFlash cards support both 3.3V and 5V operation and can be interchanged between 3.3V and 5V systems. This means that any CF card can operate at either voltage. Other small form factor flash cards may be available to operate at 3.3V or 5V, but any single card can operate at only one of the voltages"

This seems to give permission to wire CF cards into 5V systems. This would also be a wise design choice in the CF spec, because consumers avoid the hassle of making sure they have the "right voltage" card.

D0...15Data bus.
A0...10Address bus.
RESETSystem Reset.

Source Code

Sandisk"s design page has a freeware ATA Driver / FAT File System, and a circuit diagram for an IDE to CF adapter. The latter has no buffers, so it might be wise to avoid loading it with long drive cables.

Source:www.pinouts.ru

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