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.
SAM
The SAM or Synchronous Address Multiplexer is a chip that controls access to RAM memory by the 6809 CPU and the VDG (Video Display Generator).
SAM Registers
| Address | Shorthand name | Function | Effect |
|---|---|---|---|
| FFC0 | V2CLR | SAM V2 bit clear | |
| FFC1 | V2SET | SAM V2 bit set | |
| FFC2 | V1CLR | SAM V1 bit clear | |
| FFC3 | V1SET | SAM V1 bit set | |
| FFC4 | V0CLR | SAM V0 bit clear | |
| FFC5 | V0SET | SAM V0 bit set | |
| FFC6 | F0CLR | SAM F0 bit clear | |
| FFC7 | F0SET | SAM F0 set bit | add $200 to video offset |
| FFC8 | |||
| FFC9 | F1SET | SAM F1 set bit | add $400 to video offset |
| FFCA | SAM F2 bit clear | ||
| FFCB | F2SET | SAM F2 set bit | add $800 to video offset |
| FFCC | |||
| FFCD | |||
| FFCE | |||
| FFCF | |||
| FFD0 | |||
| FFD1 | |||
| FFD2 | |||
| FFD3 | |||
| FFD4 | |||
| FFD5 | |||
| FFD6 | |||
| FFD7 | |||
| FFD8 | |||
| FFD9 | |||
| FFDA | |||
| FFDB | |||
| FFDC | |||
| FFDD | |||
| FFDE | |||
| FFDF |