ATAPI Interface Chapter 5
Seagate Travan 40 Product Manual Page 87
WRITE BUFFER (Group 1, Op. Code 3B)
The WRITE BUFFER command is used in conjunction with the READ BUFFER
command as a diagnostic tool or for downloading firmware. This command tests the
ATAPI Bus and the drive’s Data Buffer. The tape is not affected. Using Buffer ID and
Buffer Offset, data can be placed in any location in the buffer.
CDB for WRITE BUFFER command
Data Bits
Byte 7 6 5 4 3 2 1 0 Hex
0 0 0 1 1 1 0 1 1 3B
1 0 0 0 0 0 Mode 0X
2 Buffer I.D. XX
3
4
5
MSB
Buffer Offset
LSB
00
00
XX
6
7
8
MSB
Transfer Length
LSB
XX
XX
XX
9 0 0 0 0 0 0 0 0 00
MODE: The Mode Bits determine the operation and format as indicated in the table
below.
Mode Bits
2 1 0 Description
0 0 0 Reserved
0 0 1 Reserved
0 1 0 Data only is written, no header.
1 0 0 Download firmware segments 1 through (N-1). Firmware is not
saved in EEPROM.
1 0 1 Download firmware segment N (last segment). Firmware is
saved (“flashed”) into EEPROM.
1 1 0 Reserved
1 1 1 Reserved
Buffer I.D.: The Data Buffer is divided into 256 equal segments. (If the buffer size is
512KB, each segment is 2K). The Buffer ID specifies the segment into which the first
byte of data transferred by the Host is to be placed.
NOTE: If the buffer size is 2048KB, each segment will be 8K bytes in size and the
maximum offset will be 09ffh.