FW82801EB Intel, FW82801EB Datasheet - Page 241

• Manufacturer Part Number: FW82801EB
• Manufacturer: Intel

Specifications of FW82801EB

• Lead Free Status / RoHS Status: Not Compliant

Intel
®
Table 115. Block Write–Block Read Process Call Protocol with/without PEC (Sheet 1 of 2)
82801EB ICH5 / 82801ER ICH5R Datasheet
Note: E32B bit in the Auxiliary Control register must be set when using this protocol.
Block Write–Block Read Process Call
The block write-block read process call is a two-part message. The call begins with a slave address
and a write condition. After the command code the host issues a write byte count (M) that describes
how many more bytes will be written in the first part of the message. If a master has 6 bytes to
send, the byte count field will have the value 6 (0000 0110b), followed by the 6 bytes of data. The
write byte count (M) cannot be 0.
The second part of the message is a block of read data beginning with a repeated start condition
followed by the slave address and a Read bit. The next byte is the read byte count (N), which may
differ from the write byte count (M). The read byte count (N) cannot be 0.
The combined data payload must not exceed 32 bytes. The byte length restrictions of this process
call are summarized as follows:
The read byte count does not include the PEC byte. The PEC is computed on the total message
beginning with the first slave address and using the normal PEC computational rules. It is highly
recommended that a PEC byte be used with the Block Write-Block Read Process Call. Software
must do a read to the command register (offset 2h) to reset the 32byte buffer pointer prior to
reading the block data register.
Note that there is no STOP condition before the repeated START condition, and that a NACK
signifies the end of the read transfer.
•
•
•
27:20
36:29
45:38
18:11
8:2
Bit
10
19
28
37
46
M ≥ 1 byte
N ≥ 1 byte
M + N ≤ 32 bytes
1
9
–
Start
Slave Address — 7 bits
Write
Acknowledge from slave
Command code — 8 bits
Acknowledge from slave
Data Byte Count (M) — 8 bits
Acknowledge from slave
Data Byte (1) — 8 bits
Acknowledge from slave
Data Byte (2) — 8 bits
Acknowledge from slave
–
Data Byte (M) — 8 bits
Acknowledge from slave
Description
Functional Description
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