MediaWiki:Sitenotice:
2025-12-29: I have restored the wiki to a backup from the end of November. Starting in September 2025, accesses went form the 800MB-1.2GB range per month to 26GB in September, 42GB in October, and 70GB in November with most accesses originating from China. As soon as I realized what was causing all the access problems in November, I shut it down (it had reached 36GB by then) behind a password/login screen. The database had gotten corrupted, and I tried a restore from just before the spike in access but that didn't work. Thus, end of November. I still have the other daily backups so if there were any important additions in December, let me know and maybe they can be recovered. - Allen H.
Synchronous Address Multiplexer
Synchronous Address Multiplexer
Supports the MC6809/HD6309 MPU interleaving memory access with the MC6847/MC6847T1 VDG and the dynamic RAM refresh cycles.
Variants
- SN74LS783 / MC6883 - used in CoCo 1/2
- SN74LS785 - used in CoCo 2B
- SAM Accelerator - an accelerated SAM allowing RAM refresh during full double-speed clock mode on CoCo 1/2 (may require upgraded PIAs too)
- SAMX4 - CPLD-based SAM replacement with additional 256K banking
- TCC1014 1986 - the 1986 version of the ACVC / GIME replaces and includes much of the SAM functionality for CoCo 1/2 backwards compatibility support
- TCC1014 1987 - the 1987 version of the ACVC / GIME also replaces and includes much of the SAM functionality for CoCO 1/2 backwards compatibility support