Basic features of the board include:
Can be used on either a SYM or an AIM.
Memory selectable on 4K boundaries covering the entire 64K address space. Not all blocks can be RAM, as the SYM-1 already has up to 4K of RAM on-board, there are multiple ROM sockets, and I/O.
The top $80 bytes are not available; that area is reserved by the SYM-1.
Can allow space for BASIC or other software in ROM. My system has an 8K BASIC ROM so I did not place RAM at C000-DFFF.
Can be ordered as a bare board, a kit, or fully assembled and tested. The bare board is just that… no components. The kit includes all components and you will need to solder the parts.
The Rev 2 boards have an additional chip which works around a bug in early AIM-65 boards. We know the problem was in rev 1 and rev 0 AIM boards, and it was definitely fixed on rev 4 boards, but I don’t know exactly which revision fixed the problem. Basically the RAM_R/W signal (pin Z on the Expansion connector) had the inverted Phase 2 clock NAND’ed with R/W. The SYM and AIM were both supposed to follow the KIM standard, but Rockwell got this one signal wrong.
Rev 2 boards have replaced the jumpers with a pair of 8 position DIP switches; those are easier to set and there are no jumpers to get lost ??
When running the ROM BASIC, this is what gets displayed:
MEMORY SIZE? WIDTH? 32255 BYTES FREE BASIC V1.1 COPYRIGHT 1978 SYNERTEK SYSTEMS CORP.
Nice.
I’ve configured RAM from 1000-7FFF, B000-BFFF, and F000-FF7F. That gives a lot of room to squeeze in useful add-ons to the monitor.
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SYM AIM 60K RAM docx |
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SYM AIM 60K RAM pdf |
