IDE Configuration

Bit

Description

 

 

7:6

Secondary Drive 1 IORDY Sample Point (SISP1). This field selects the number of PCI clocks

 

between SDIOx# assertion and the first SIORDY sample point for the slave drive on the secondary

 

channel.

 

Bits[7:6] Number of Clocks

 

00 5

 

01 4

 

10 3

 

11 2

 

 

5:4

Secondary Drive 1 Recovery Time (SRTC1). This field selects the minimum number of PCI

 

clocks between the last SIORDY# sample point and the SDIOx# strobe of the next cycle for the

 

slave drive on the secondary channel.

 

Bits[5:4] Number of Clocks

 

00 4

 

01 3

 

10 2

 

11 1

 

 

3:2

Primary Drive 1 IORDY Sample Point (PISP1). This field selects the number of PCI clocks

 

between PDIOx# assertion and the first PIORDY sample point for the slave drive on the primary

 

channel.

 

Bits[3:2] Number of Clocks

 

00 5

 

01 4

 

10 3

 

11 2

 

 

1:0

Primary Drive 1 Recovery Time (PRTC1). This field selects the minimum number of PCI clocks

 

between the last PIORDY# sample point and the PDIOx# strobe of the next cycle for the slave

 

drive on the primary channel.

 

Bits[1:0] Number of Clocks

 

00 4

 

01 3

 

10 2

 

11 1

 

 

12.2.12DMACTL–Synchronous DMA Control Register (Function 1)

Address Offset:

48h

Default Value:

00h

Attribute:

Read/Write

This register enables each individual channel and drive for Synchronous DMA transfers. For nonsynchronous DMA operation, this register should be left programmed to its default value.

Bit

Description

7:4 Reserved.

3Secondary Drive 1 SDMA Enable (SSDE1). 1 = Enable Synchronous DMA mode for secondary channel drive 1. 0 = Disable (default).

2Secondary Drive 0 SDMA Enable (SSDE0). 1 = Enable Synchronous DMA mode for secondary channel drive 0. 0 = Disable (default).

1Primary Drive 1 SDMA Enable (PSDE1). 1 = Enable Synchronous DMA mode for primary channel drive 1. 0 = Disable (default).

0Primary Drive 0 SDMA Enable (PSDE0). 1 = Enable Synchronous DMA mode for primary channel drive 0. 0 = Disable (default).

Intel® 460GX Chipset Software Developer’s Manual

12-7