Emerson 752I ユーザーズマニュアル

 IPMI Message Protocol

752i User’s Manual

The Master Write-Read I

2

C command allows for direct accesses to I

2

C devices. This com-

mand can read from or write to any of the Zircon PM’s private I

2

C devices, such as SROMs or 

temperature sensors. Typically, you would use it to update the Zircon PM’s firmware from 
the management controller. 

 shows the request/response data parameters for 

this command.

Table 11-10:

Request 
Data

1

Bus  ID
Bits[7:4], Channel Number. Write as 0000 (binary).
Bits[3:1], Bus ID, zero-based
000=Public IPMB 
001=Private IIC Bus #1, Private IPMB
111=Private IIC Bus #2
Bit[0], Bus Type
0=Public (IPMB)
1=Private Bus

2

Bits[7:1], Slave Address of Recipient
Bit[0], Reserved. Write as zero.

3

Read Count. Number of bytes to read, one-based.
0=No bytes to read.

4:M

Data to Write

Response 
Data

1

Completion  Code
A management controller shall return an error Completion Code 
if an attempt is made to access an unsupported bus. 
Generic, plus following command-specific codes (hex):
81=Lost Arbitration
82=Bus Error
83=NAK on Write
84=Truncated Read

2:N

Bytes read from specified slave address. This field will be absent if 
the read count is 0. The controller terminates the I

2

C transaction 

with a STOP condition after reading the requested number of 
bytes.