NH82801DB S L8DE Intel, NH82801DB S L8DE Datasheet - Page 226

• Manufacturer Part Number: NH82801DB S L8DE
• Manufacturer: Intel

Specifications of NH82801DB S L8DE

• Lead Free Status / RoHS Status: Compliant

Functional Description
5.18.7.3
226
Table 5-97. Data Values for Slave Read Registers (Sheet 2 of 2)
Note: An external microcontroller must not attempt to access the ICH4’s SMBus Slave logic until at least
Note: Host software must always clear the HOST_NOTIFY_STS bit after completing any necessary
5.18.7.2.1 Behavioral Notes
According to SMBus protocol, Read and Write messages always begin with a Start bit–Address–
Write bit sequence. When the ICH4 detects that the address matches the value in the Receive Slave
Address register, it will assume that the protocol is always followed and ignore the Write bit (bit 9)
and signal an Acknowledge during bit 10 (See
Start–Address–Read occurs (which is illegal for SMBus Read or Write protocol) and the address
matches the ICH4’s Slave Address, the ICH4 will still grab the cycle.
Also according to SMBus protocol, a Read cycle contains a Repeated Start–Address–Read
sequence beginning at bit 20 (See
Receive Slave Address, it will assume that the protocol is followed, ignore bit 28, and proceed with
the Slave Read cycle.
1 second after both RTCRST# and RSMRST# are deasserted (high).
Format of Host Notify Command
The ICH4 tracks and responds to the standard Host Notify command as specified in the SMBus 2.0
specification. The host address for this command is fixed to 0001000b. If the ICH4 already has
data for a previously-received host notify command which has not been serviced yet by the host
software (as indicated by the HOST_NOTIFY_STS bit), then it will NACK following the host
address byte of the protocol. This allows the host to communicate non-acceptance to the master and
retain the host notify address and data values for the previous cycle until host software completely
services the interrupt.
reads of the address and data registers.
Register
9–FFh
4
4
4
5
5
5
5
6
7
8
Bits
6:4
7:3
7:0
7:0
7:0
7:0
3
7
0
1
2
This bit will be set after the TCO timer times out a second time (Both TIMEOUT and
SECOND_TO_STS bits set).
Reserved.
The bit will reflect the state of the GPI[11]/SMBALERT# signal, and will depend on the
GP_INV[11] bit. It does not matter if the pin is configured as GPI[11] or SMBALERT#.
Unprogrammed FWH bit. This bit will be 1 to indicate that the first BIOS fetch returned FFh,
which indicates that the FWH is probably blank.
Reserved
CPU Power Failure Status: 1 if the CPUPWR_FLR bit in the GEN_PMCON_2 register is
set.
Reserved
Contents of the Message 1 register. See
Contents of the Message 2 register. See
Contents of the WDSTATUS register. See
Reserved
• If the GP_INV[11] bit is 1 then the value of register 4 bit 7 will equal the level of the
• If the GP_INV[11] bit is 0 then the value of register 4 bit 7 will equal the inverse of the
GPI[11]/SMBALERT# pin (high = 1, low = 0).
level of the GPI[11]/SMBALERT# pin (high = 1, low = 0).
Table 5-98
shows the Host Notify format.
Table
5-96). Once again, if the Address matches the ICH4’s
Table 5-93
Description
Section
Section
Section
and
9.9.9.
9.9.9.
9.9.10.
Table
Intel
5-96). In other words, if a
®
82801DB ICH4 Datasheet