SC2200 NSC [National Semiconductor], SC2200 Datasheet - Page 301

• Manufacturer Part Number: SC2200
• Description: Thin Client On a Chip
• Manufacturer: NSC [National Semiconductor]

Revision 3.0
Core Logic Module
5.4.7
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
categories:
I/O Port 000h
Written as two successive bytes, byte 0, 1.
I/O Port 001h
Written as two successive bytes, byte 0, 1.
I/O Port 002h
Written as two successive bytes, byte 0, 1.
I/O Port 003h
Written as two successive bytes, byte 0, 1.
I/O Port 004h
Written as two successive bytes, byte 0, 1.
I/O Port 005h
Written as two successive bytes, byte 0, 1.
I/O Port 006h
Written as two successive bytes, byte 0, 1.
I/O Port 007h
Written as two successive bytes, byte 0, 1.
I/O Port 008h (R/W)
Read
Bit
7
6
5
4
3
ISA Legacy Register Space
Description
Channel 3 Request. Indicates if a request is pending.
0: No.
1: Yes.
Channel 2 Request. Indicates if a request is pending.
0: No.
1: Yes.
Channel 1 Request. Indicates if a request is pending.
0: No.
1: Yes.
Channel 0 Request. Indicates if a request is pending.
0: No.
1: Yes.
Channel 3 Terminal Count. Indicates if TC was reached.
0: No.
1: Yes.
(Continued)
Table 5-43. DMA Channel Control Registers
DMA Channel 0 Transfer Count Register (R/W)
DMA Channel 1 Transfer Count Register (R/W)
DMA Channel 2 Transfer Count Register (R/W)
DMA Channel 3 Transfer Count Register (R/W)
DMA Channel 0 Address Register (R/W)
DMA Channel 1 Address Register (R/W)
DMA Channel 2 Address Register (R/W)
DMA Channel 3 Address Register (R/W)
DMA Status Register, Channels 3:0
301
• DMA Channel Control Registers, see Table 5-43
• DMA Page Registers, see Table 5-44
• Programmable Interval Timer Registers, see Table 5-45
• Programmable Interrupt Controller Registers, see Table
• Keyboard Controller Registers, see Table 5-47
• Real-Time Clock Registers, see Table 5-48
• Miscellaneous Registers, see Table 5-49 (includes 4D0h
5-46
and 4D1h Interrupt Edge/Level Select Registers)
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