AMD SC3200 manual ISA Legacy Register Space, DMA Channel Control Registers

Core Logic Module - ISA Legacy Register Space 32581C

6.4.7ISA Legacy Register Space

The ISA Legacy registers reside in the ISA I/O address space in the address range from 000h to FFFh and are accessed through typical input/output instructions (i.e., CPU direct R/W) with the designated I/O port address and 8-bit data.

The bit formats for the ISA Legacy I/O Registers plus two chipset-specific configuration registers used for interrupt mapping in the Core Logic module are given in this section. The ISA Legacy registers are separated into the following DMA Channel Control Registers, see Table 6-43

•DMA Page Registers, see Table 6-44

•Programmable Interval Timer Registers, see Table 6-45

•Programmable Interrupt Controller Registers, see Table 6-46

•Keyboard Controller Registers, see Table 6-47

•Real-Time Clock Registers, see Table 6-48

•Miscellaneous Registers, see Table 6-49(includes 4D0h and 4D1h Interrupt Edge/Level Select Registers)

		Table 6-43. DMA Channel Control Registers
Bit	Description
I/O Port 000h		DMA Channel 0 Address Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 001h		DMA Channel 0 Transfer Count Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 002h		DMA Channel 1 Address Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 003h		DMA Channel 1 Transfer Count Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 004h		DMA Channel 2 Address Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 005h		DMA Channel 2 Transfer Count Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 006h		DMA Channel 3 Address Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 007h		DMA Channel 3 Transfer Count Register (R/W)
Written as two successive bytes, byte 0, 1.
I/O Port 008h (R/W)
Read		DMA Status Register, Channels 3:0
7	Channel 3 Request. Indicates if a request is pending.
	0:	No.
	1:	Yes.
6	Channel 2 Request. Indicates if a request is pending.
	0:	No.
	1:	Yes.
5	Channel 1 Request. Indicates if a request is pending.
	0:	No.
	1:	Yes.
4	Channel 0 Request. Indicates if a request is pending.
	0:	No.
	1:	Yes.
3	Channel 3 Terminal Count. Indicates if TC was reached.
	0:	No.
	1:	Yes.

AMD Geode™ SC3200 Processor Data Book 295