SanDisk SDDR-01 - ImageMate External Parallel CompactFlash Card Reader Manual descarregar pdf (Página 46)

CompactFlash Memory Card Product Manual Preliminary

5.2 Contiguous I/O Mapped Addressing

When the system decodes a contiguous block of

I/O registers to select the CompactFlash Memory

Card, the registers are accessed in the block of I/O

space decoded by the system as follows:

Table 5-3 Contiguous I/O Decoding

-REG A3 A2 A1 A0 Offset -IORD=0 -IOWR=0 Notes

0 0 0 0 0 0 Even RD Data Even WR Data 1

0 0 0 0 1 1 Error Features 2

0 0 0 1 0 2 Sector Count Sector Count

0 0 0 1 1 3 Sector No. Sector No.

0 0 1 0 0 4 Cylinder Low Cylinder Low

0 0 1 0 1 5 Cylinder High Cylinder High

0 0 1 1 0 6 Select Card /Head Select Card/Head

0 0 1 1 1 7 Status Command

0 1 0 0 0 8 Dup Even RD Data Dup. Even WR Data 2

0 1 0 0 1 9 Dup. Odd RD Data Dup. Odd WR Data 2

0 1 1 0 1 D Dup. Error Dup. Features 2

0 1 1 1 0 E Alt Status Device Ctl

0 1 1 1 1 F Drive Address Reserved

Notes: 1. Register 0 is accessed with -CE1 low and -CE2 low (and A0 = Don't Care) as a word register on the combined Odd

Data Bus and Even Data Bus (D15-D0). This register may also be accessed by a pair of byte accesses to the offset 0

with -CE1 low and -CE2 high. Note that the address space of this word register overlaps the address space of the Error

and Feature byte-wide registers that lie at offset 1. When accessed twice as byte register with -CE1 low, the first byte

to be accessed is the even byte of the word and the second byte accessed is the odd byte of the equivalent word access.

A byte access to register 0 with -CE1 high and -CE2 low accesses the error (read) or feature (write) register.

2. Registers at offset 8, 9 and D are non-overlapping duplicates of the registers at offset 0 and 1.

accessed in the order 9 then 8 the data will be transferred odd byte then even byte.

Repeated byte accesses to register 8 or 0 will access consecutive (even than odd) bytes from the data buffer. Repeated

word accesses to register 8, 9 or 0 will access consecutive words from the data buffer. Repeated byte accesses to

(even then odd) bytes from the data buffer. Byte accesses to register 9 access only the odd byte of the data.

3. Address lines which are not indicated are ignored by the CompactFlash Memory Card for accessing all the registers

in this table.

1 2 ... 41 42 43 44 45 46 47 48 49 50 51 ... 117 118

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SanDisk SDDR-01 - ImageMate External Parallel CompactFlash Card Reader Manual Página 46