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Core Logic Module - IDE Controller Registers - Function 2

6.4.3.1IDE Controller Support Registers

F2 Index 20h, Base Address Register 4 (F2BAR4), points to the base address of where the registers for IDE control- ler configuration are located. Table 6-36gives the bit for-

mats of the I/O mapped IDE Controller Configuration registers that are accessed through F2BAR4.

Table 6-36. F2BAR4+I/O Offset: IDE Controller Configuration Registers

Bit

Description

 

 

 

 

 

Offset 00h

 

IDE Bus Master 0 Command Register — Primary (R/W)

Reset Value: 00h

 

 

 

7:4

Reserved. Must be set to 0. Must return 0 on reads.

 

 

 

 

3

Read or Write Control. Sets the direction of bus master transfers.

 

 

0: PCI reads performed.

 

 

1:

PCI writes performed.

 

 

This bit should not be changed when the bus master is active.

 

 

 

 

2:1

Reserved. Must be set to 0. Must return 0 on reads.

 

 

 

 

0

Bus Master Control. Controls the state of the bus master.

 

 

0:

Disable master.

 

 

1:

Enable master.

 

 

Bus master operations can be halted by setting this bit to 0. Once an operation has been halted, it cannot be resumed. If this

 

bit is set to 0 while a bus master operation is active, the command is aborted and the data transferred from the drive is dis-

 

carded. This bit should be reset after completion of data transfer.

 

 

 

 

 

Offset 01h

 

Not Used

 

 

 

 

 

Offset 02h

 

IDE Bus Master 0 Status Register — Primary (R/W)

Reset Value: 00h

 

 

7

Simplex Mode. (Read Only) Indicates if both the primary and secondary channel operate independently.

 

0:

Yes.

 

 

1: No (simplex mode).

 

 

 

 

6

Drive 1 DMA Enable. When asserted, allows Drive 1 to perform DMA transfers.

 

 

0:

Disable.

 

 

1:

Enable.

 

 

 

 

5

Drive 0 DMA Enable. When asserted, allows Drive 0 to perform DMA transfers.

 

 

0:

Disable.

 

 

1:

Enable.

 

 

 

 

4:3

Reserved. Must be set to 0. Must return 0 on reads.

 

 

 

 

2

Bus Master Interrupt. Indicates if the bus master detected an interrupt.

 

 

0:

No.

 

 

1: Yes. Write 1 to clear.

 

 

 

 

1

Bus Master Error. Indicates if the bus master detected an error during data transfer.

 

 

0:

No.

 

 

1: Yes. Write 1 to clear.

 

 

 

 

0

Bus Master Active. Indicates if the bus master is active.

 

 

0:

No.

 

 

1:

Yes.

 

 

 

 

 

Offset 03h

 

Not Used

 

 

 

 

Offset 04h-07h

IDE Bus Master 0 PRD Table Address — Primary (R/W)

Reset Value: 00000000h

 

 

31:2

Pointer to the Physical Region Descriptor Table. This bit field contains a PRD table pointer for IDE Bus Master 0.

 

When written, this field points to the first entry in a PRD table. Once IDE Bus Master 0 is enabled (Command Register bit 0

 

= 1), it loads the pointer and updates this field (by adding 08h) so that is points to the next PRD.

 

 

When read, this register points to the next PRD.

 

 

 

 

1:0

Reserved. Must be set to 0.

 

 

 

 

 

 

 

 

260

 

AMD Geode™ SC1200/SC1201 Processor Data Book

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AMD SC1200, SC1201 manual IDE Controller Support Registers, 260