Memory; System Memory Map; System I/O Map - DIGITAL-LOGIC Microspace MSM586SEN Technical User Manual

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5.7

Memory

5.7.1

System Memory Map

The ELAN520 CPU used as central processing unit on the MICROSPACE has a memory address space
which is defined by 32 address bits. Therefore, it can address 1 GByte of memory. The memory address
MAP is as follows:
CPU
Address:
000000 - 09FFFFh
0A0000 - 0BFFFFh
0C0000 - 0CBFFFh
0CC000 - 0CFFFFh
0D0000 - 0D4000h
0D4000 - 0D8000h
0D8000 - 0DFFFFh
0E0000 - 0EFFFFh
0F0000 - 0FFFFFh
100000 - 1FFFFFh
200000 - FFFFFFh
See also BIOS manual for additional details
5.7.2

System I/O map

The following table shows the detailed listing of the I/O port assignments used in the MICROSPACE board:
I/O Ad- Read/Write
dress Status
0000h R / W
0001h R / W
0002h R / W
0003h R / W
0004h R / W
0005h R / W
0006h R / W
0007h R / W
0008h R
Size: Function / Comments:
640 KBytes Onboard DRAM for DOS applications
128 KBytes CGA, EGA, LCD Video RAM 128kB
48 KBytes VGA BIOS selected by the hardware
16 KBytes BIOS extensions selected by the hardware
16 KBytes free for user
16 KBytes free for user
32 KBytes free for user
64 KBytes BIOS
64 KBytes BIOS
1 MByte DRAM for extended onboard memory
14 MBytes DRAM for extended onboard memory
Description
DMA channel 0 address byte 0 (low), then byte 1
DMA channel 0 word count byte 0 (low), then byte 1
DMA channel 1 address byte 0 (low), then byte 1
DMA channel 1 word count byte 0 (low), then byte 1
DMA channel 2 address byte 0 (low), then byte 1
DMA channel 2 word count byte 0 (low), then byte 1
DMA channel 3 address byte 0 (low), then byte 1
DMA channel 3 word count byte 0 (low), then byte 1
DMA channel 0-3 status register
bit 7 = 1 Channel 3 request
bit 6 = 1 Channel 2 request
bit 5 = 1 Channel 1 request
bit 4 = 1 Channel 0 request
bit 3 = 1 Terminal count on channel 3
bit 2 = 1 Terminal count on channel 2
bit 1 = 1 Terminal count on channel 1
bit 0 = 1 Terminal count on channel 0
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