82371FB Datasheet, PDF (48/122 Pages) Intel Corporation – 82371FB (PIIX) AND 82371SB (PIIX3) PCI ISA IDE XCELERATOR

82371FB (PIIX) AND 82371SB (PIIX3)
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2.3.3. PCICMD—COMMAND REGISTER (Function 1)
Address Offset:
Default Value:
Attribute:
04–05h
0000h
Read/Write
The PCICMD Register controls access to the I/O space registers.
Bit
15:10
9
8:5
4
3
2
1
0
Description
Reserved. Read 0.
Fast Back to Back Enable (FBE). (Not Implemented) This bit is hardwired to 0.
Reserved. Read as 0.
Memory Write and Invalidate Enable (MWI). (Not Implemented) This bit is hardwired to 0.
Special Cycle Enable (SCE). (Not Implemented) This bit is hardwired to 0
Bus Master FunctionEnable (BME). 1=Enable. 0=Disable.
Memory Space Enable (MSE). (Not Implemented) This bit is hardwired to 1.
I/O Space Enable (IOSE). This bit controls access to the I/O space registers. When
IOSE=1, access to the Legacy IDE ports (both primary and secondary) and the PCI Bus
Master IDE I/O Registers is enabled. The Base Address Register for the PCI Bus Master IDE
I/O Registers should be programmed before this bit is set to 1.
2.3.4. PCISTS—PCI DEVICE STATUS REGISTER (Function 1)
Address Offset:
Default Value:
Attribute:
06–07h
0280h
Read/Write
PCISTS is a 16-bit status register for the IDE interface function. The register also indicates the PIIX's
DEVSEL# signal timing.
Bit
Description
15
Detected Parity Error (PERR). (Not Implemented) Read as 0.
14
SERR# Status (SERRS). (Not Implemented) Read as 0.
13
Master-Abort Status (MAS)—R/W. When the Bus Master IDE interface function, as a master,
generates a master abort, MA is set to a 1. Software sets MA to 0 by writing a 1 to this bit.
12
Received Target-Abort Status (RTA)—R/W. When the Bus Master IDE interface function is a
master on the PCI Bus and receives a target abort, this bit is set to a 1. Software sets RTA to 0
by writing a 1 to this bit.
11
Signaled Target Abort Status (STA)—R/W. This bit is set when the PIIX/PIIX3 IDE interface
function is targeted with a transaction that the PIIX/PIIX3 terminates with a target abort.
Software resets STA to 0 by writing a 1 to this bit..
10:9 DEVSEL# Timing Status (DEVT)—RO. For the PIIX, DEVT=01 indicating medium timing for
DEVSEL# assertion when performing a positive decode. DEVSEL# timing does not include
configuration cycles.
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