Datasheet
Functional Description
Intel® Xeon® Processor D-1500 Product Family 149
Datasheet - Volume 1 of 4: Integrated Platform Controller Hub
March 2015
I
2
C Read
This command allows Intel® Xeon® Processor D-1500 Product Family to perform block
reads to certain I
2
C* devices, such as serial E
2
PROMs. The SMBus Block Read supports
the 7-bit addressing mode only.
However, this does not allow access to devices using the I
2
C “Combined Format” that
has data bytes after the address. Typically these data bytes correspond to an offset
(address) within the serial memory chips.
Note: This command is supported independent of the setting of the I2C_EN bit. The I
2
C Read
command with the PEC_EN bit set produces undefined results. Software must force
both the PEC_EN and AAC bit to 0 when running this command.
For I
2
C Read command, the value written into bit 0 of the Transmit Slave Address
Register (SMB I/O register, offset 04h) needs to be 0.
The format that is used for the command is shown in Table 3- 4 0 .
Intel® Xeon® Processor D-1500 Product Family will continue reading data from the
peripheral until the NAK is received.
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.
Table 3-40. I
2
C* Block Read
Bit Description
1Start
8:2 Slave Address – 7 bits
9Write
10 Acknowledge from slave
18:11 Send DATA1 register
19 Acknowledge from slave
20 Repeated Start
27:21 Slave Address – 7 bits
28 Read
29 Acknowledge from slave
37:30 Data byte 1 from slave – 8 bits
38 Acknowledge
46:39 Data byte 2 from slave – 8 bits
47 Acknowledge
– Data bytes from slave / Acknowledge
– Data byte N from slave – 8 bits
–NOT Acknowledge
–Stop