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(1)
Mode = 0 0 0: Header + data, without address specification
When this mode is specified, the data stored in the IDD's data buffer are transferred to the
INIT after the 4-byte header. Zero must be specified in the "Buffer address" field in the CDB.
The "Transfer byte count" field in the CDB specifies the total number of bytes of the header
and buffer data which can be received by the INIT. The IDD reads the data from the data
buffer from the top (Address X '000000'), then adds the 4-byte header to it and transfers it to
the INIT. Data transfer is completed at the point when the number of bytes of the header and
data from the IDD's data buffer, specified in the "Transfer byte length" field, has been
transferred, or at the point when transfer of the header and all the data in the IDD's data buffer,
to the final byte position, has been completed. When zero is specified in the "Transfer byte
length" field, this command is terminated without executing a data transfer.
The format of the data transferred to the INIT when this mode is specified is shown in Figure
4.31.
Bit
Byte
0
1
Header
2
3
4
5
Data
~
~
n
Figure 4.31 READ BUFFER command: buffer data (Mode = 000, 001)
The "Effective buffer data length" field in the header indicates the size of the data buffer (byte
length). This value indicates the size of the IDD's data buffer that can be used by the WRITE
BUFFER and READ BUFFER commands without relation to the length specified in the
"Transfer byte length" field in the CDB or the length of the data actually stored in the data
buffer by the WRITE BUFFER command. When this mode is specified, the "Effective buffer
data length" shows the size (cache segment volume) of the IDD's entire data buffer area.
Also, the length of the buffer data transferred to the INIT by this command is the value for the
number of bytes in the ["Transfer byte length" field in the CDB – 4 bytes] or the value
indicated in the "Effective buffer data length" field in the header, whichever is smaller.
4 - 128
7
6
5
0
0
0
Effective Buffer Data Length (MSB)
Effective Buffer Data Length
Effective Buffer Data Length (LSB)
Buffer Data (Byte 0)
Buffer Data (Byte 1)
~
~
Buffer Data (Byte n–4)
C141-E054-02EN
4
3
2
1
0
0
0
0
0
0
~
~
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