Cmd53 Data Transfer Format; Special Timing For Cmd53 Multi-Block Read; Table 5-3 Byte Count Values - iHome SDIO Card Specification Sheet

SDIO Simplified Specification Version 2.00
Register Address:
Byte/Block Count
Count Value
Bytes Transferred
Block Transferred
CRC7:
E(nd bit):
The response from the SDIO card to CMD53 shall be R5 (the same as CMD52) as defined in 5.2. For CMD53,
the 8-bit data field shall be stuff bits and shall be read as 0x00. Also, the ERROR response bit shall be type "E R
X" (see Table 5-1 ).
5.3.1

CMD53 Data Transfer Format

When executing the IO_RW_EXTENDED (CMD53), the multi-byte or multi-block data transfer is similar to the
data transfer for memory. For the multi-byte transfer modes (block mode=0) the following applies:
IO_RW_EXTENDED byte read is similar to CMD17 (READ_SINGLE_BLOCK)
IO_RW_EXTENDED byte write is similar to CMD24 (WRITE_BLOCK)
Note that the byte count for this transfer is set in the command, rather than the fixed block size. Thus, the size of
the data payload is in the range of 1-512 bytes. The block mode is similar to the following memory commands:
IO_RW_EXTENDED block read is similar to CMD18 (READ_MULTIPLE_BLOCK)
IO_RW_EXTENDED block write is similar to CMD25 (WRITE_MULTIPLE_BLOCK)
For the block mode the only difference is that for a fixed block count, the host does not need to stop the transfer,
as it continues until the block count is satisfied. If the block count is set to zero, the operation is identical to the
memory mode in that the host must stop the transfer.
5.3.2

Special Timing for CMD53 Multi-Block Read

This section is not included in the Simplified Specification.
address that increment by 1 after each operation. This command is used when large
amounts of I/O data exist within the I/O card in a RAM like data buffer. In this
operation, the start address is loaded into the Register Address field. The first
operation occurs at that address within the I/O card. The next operation shall occur
at address+1 with the address incrementing by 1 until the operation has completed.
As with OP Code 0, the number of bytes is set in the Byte Count field of the
command.
Start Address of I/O register to read or write. Range is [0x1FFFF:0]
If the command is operating on bytes (Block Mode = 0), this field contains the
number of bytes to read or write. A value of 0x000 shall cause 512 bytes to be read
or written.
0x000
512
∞

Table 5-3 Byte Count Values

If the command is in block mode (Block Mode=1), the Block Count field specifies the
number of Data Blocks to be transferred following this command. A value of 0x000
indicates that the count set to infinite. In this case, the I/O blocks shall be transferred
until the operation is aborted by writing to the I/O abort function select bits (ASx) in
the CCCR (see Table 6-1 and Table 6-2). Table 5-3 shows the relationship between
the value in the command and the actual number of bytes transferred.
7 bits of CRC data
End bit, always 1
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0x001 0x002 ----
1 2
1 2
25
0x1FF
511
511