Emerson 752I Master Write-Read I2C (Application)

IPMI Controller: IPMI Message Protocol
Katana®752i User’s Manual 10006024-04
11-14
Master Write-Read I2C (Application)
The Master Write-Read I2C command allows for direct accesses to I2C devices. This com-
mand can read from or write to any of the Zircon PM’s private I2C devices, such as SROMs or
temperature sensors. Typically, you would use it to update the Zircon PM’s firmware from
the management controller. Table11-10 shows the request/response data parameters for
this command.
Table 11-10: Master Write-Read I2C Parameters
Type: Byte: Data Field:
Request
Data
1Bus 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
1Completion 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 I2C transaction
with a STOP condition after reading the requested number of
bytes.