Description
Discontinuation Notice: After 1/31/2023 only bare boards will be available for this product.
For those using a 6809 system with Dynamic Address Translation (DAT), this is the highest density memory card ever offered for the SS-50 bus! This is a one megabyte RAM board that works with extended addressing as found on SWTPC and Corsham Tech 6809 CPU boards.
- 1 MB static RAM – very low power consumption
- Each 64 bank can be individually enabled/disabled via two DIP switches
- A16-A19 can be selectively disabled; allows use of some extended address lines for baud rate clocks
- Fully assembled, tested, and burned-in
If you aren’t familiar with the DAT system, it was SWTPCs solution to allow more than 64K of memory to be addressed by their 6809 board. The upper four bits of the address bus select one of 16 RAM locations (dedicated RAM, not system RAM) which contain A12-A19 which are then put onto the bus to select which exact 4K block of memory is to appear for that address range. Ie, this doesn’t produce a real 20 bit address bus, but does allow multiple pages from a 1 MB range to be mapped into any 4K block in the 6809’s 64K address space.
Now the bad news… I am not aware of any program that actually uses the extended addressing, except for the XMEMTEST memory test tool that comes with our 6809 CPU board. However, for someone who wants to experiment with more memory, this board is your answer!
