BD82HM55QMNT Datasheet, PDF (228/934 Pages) Intel Corporation – Intel® 5 Series Chipset and Intel® 3400 Series Chipset

Functional Description
5.20.7.2 Format of Read Command
The external master performs Byte Read commands to the PCH SMBus Slave interface.
The “Command” field (bits 18:11) indicate which register is being accessed. The Data
field (bits 30:37) contain the value that should be read from that register.
Table 5-46. Slave Read Cycle Format
Bit
Description
Driven by
Comment
1 Start
External Microcontroller
2-8 Slave Address - 7 bits External Microcontroller
9 Write
10 ACK
External Microcontroller
PCH
11-18 Command code – 8 bits External Microcontroller
19 ACK
20 Repeated Start
21-27 Slave Address - 7 bits
28 Read
29 ACK
PCH
External Microcontroller
External Microcontroller
External Microcontroller
PCH
30-37 Data Byte
PCH
38 NOT ACK
39 Stop
External Microcontroller
External Microcontroller
Must match value in Receive Slave
Address register
Always 0
Indicates which register is being
accessed. See Table 5-47 below
for list of implemented registers.
Must match value in Receive Slave
Address register
Always 1
Value depends on register being
accessed. Table 5-47 below for list
of implemented registers.
Table 5-47. Data Values for Slave Read Registers (Sheet 1 of 2)
Register Bits
Description
0
7:0
Reserved for capabilities indication. Should always return 00h. Future
chips may return another value to indicate different capabilities.
System Power State
1
2:0 000 = S0 001 = S1 010 = Reserved 011 = S3
100 = S4 101 = S5 110 = Reserved 111 = Reserved
7:3 Reserved
2
3:0
eserRved
7:4 Reserved
Watchdog Timer current value Note that Watchdog Timer has 10 bits,
3
5:0 but this field is only 6 bits. If the current value is greater than 3Fh, the
PCH will always report 3Fh in this field.
7:6 Reserved
4
0
1 = The Intruder Detect (INTRD_DET) bit is set. This indicates that the
system cover has probably been opened.
1
1 = BTI Temperature Event occurred. This bit will be set if the PCH’s
THRM# input signal is active. Else this beat will read “0.”
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