Intel 460GX - Manual (Page 235)

Intel® 460GX Chipset Software Developer’s Manual 12-3
IDE Configuration
12.2.4 PCISTS–PCI Device Status Register (Function 1)
Address Offset: 06–07h
Default Value: 0280h
Attribute: Read/Write
PCISTS is a 16-bit status register for the IDE interface Function. The register also indicates the
IFB's DEVSEL# signal timing.
12.2.5 CLASSC–Class Code Register (Function 1)
Address Offset: 09-0Bh
Default Value: 010180h
Attribute: Read only
This register identifies the Base Class Code, Sub-Class Code, and Device Programming interface
for IFB PCI Function 1.
Bit Description
15 Detected Parity Error. Read as 0.
14 SERR# Status. Read as 0.
13 Master-Abort Status (MAS)–R/WC. When the Bus Master IDE interface Function, as a master,
generates a master abort, MAS is set to a 1. Software sets MAS to 0 by writing a 1 to this bit.
12 Received Target-Abort Status (RTA)–R/WC. 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/WC. This bit is set when the IFB IDE interface Function
is targeted with a transaction that the IFB 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 IFB, DEVT=01 indicating medium timing for
DEVSEL# assertion when performing a positive decode. DEVSEL# timing does not include
configuration cycles.
8 Data Parity Detected (DPD). Read as 0.
7 Fast Back to back Capable (FBC)–RO. Hardwired to a 1.
6:0 Reserved.
Bit Description
23:16 Base Class Code (BASEC). 01h=Mass storage device.
15:8 Sub-Class Code (SCC). 01h=IDE controller.
7:0 Programming Interface (PI). 80h=Capable of IDE bus master operation.