cmd6686gx manual - RTD Embedded Technologies, Inc.
cmd6686gx manual - RTD Embedded Technologies, Inc.
cmd6686gx manual - RTD Embedded Technologies, Inc.
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Memory Map<br />
The module addresses memory using 24 address lines. This allows a maximum of 2 24 locations, or<br />
16 Megabytes of memory.<br />
The table below shows how memory in the first megabyte is allocated in the system.<br />
FFFFFH-<br />
C0000H<br />
ROM<br />
EFFFFH-<br />
C0000H<br />
BFFFFH-<br />
A0000H<br />
9FFFFH-<br />
00502H<br />
00501H-<br />
00400H<br />
003FFH-<br />
00000H<br />
First Megabyte Memory Map<br />
256 KB BIOS in Flash EPROM, shadowed into DRAM during<br />
runtime.<br />
Run time user memory space. Usually, memory between<br />
C0000H and C7FFFH is used for the BIOS of add-on VGA<br />
video cards.<br />
Normally used for video RAM as follows:<br />
CGA<br />
EGA/VGA<br />
Monochrome<br />
DOS reserved memory area<br />
BIOS data area<br />
Interrupt vector area<br />
0B8000H to 0BFFFFH<br />
0A0000H to 0AFFFFH<br />
0B0000H to 0B7FFFH<br />
Memory beyond the first megabyte can be accessed in real mode, by using EMS or a similar memory<br />
manager. See your OS or programming language references for information on memory managers.<br />
74
Change language