ADuC812 Evaluation Board Reference Guide
Note: This link can also be used with the Accutron ACE emulator. The single pin emulator
simply connects to this link.
LK12 (3x1) External Data Memory
Function: This link is used to configure the external data memory map. Either the bottom 32k Bytes of
the external data memory space is mapped or the bottom 256 bytes in the first 128 pages is
mapped. (via A16-A23 and U4).
Use :
Slide LK12 to Position A to make U14 transparent. Hence the external data memory (U7) sees
address lines A0-A14. Hence the bottom 32K Bytes of the address range are mapped into the
external data memory space.
Note: In this mode (using less than 64k Bytes of XRAM) the latch U14 is unnecessary.
Slide LK9 to Position B to allow ALE to latch U14. Hence the external data memory (U7)
sees the address lines A0-A7 and A16-A22. Hence the bottom 256 Bytes in the first 128 pages
of the address range are mapped into the external data memory space.
Note: This mode may not be of particular use to the user but it does show the 24 bit
addressing ability of the MicroConverter.
