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: Difference between revisions
m →SAM Registers: whoops |
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| Line 32: | Line 32: | ||
|V0SET | |V0SET | ||
|SAM V0 bit set | |SAM V0 bit set | ||
|- | |||
|FFC6 | |||
|F0CLR | |||
|SAM F0 bit clear | |||
|- | |- | ||
|FFC7 | |FFC7 | ||
| | |F0SET | ||
|SAM | |SAM F0 set bit to add $200 to video offset | ||
|- | |- | ||
|FFC8 | |FFC8 | ||
| Line 43: | Line 47: | ||
|FFC9 | |FFC9 | ||
|VOFS2 | |VOFS2 | ||
|SAM | |SAM F1 set bit to add $400 to video offset | ||
|- | |- | ||
|FFCA | |FFCA | ||
| | | | ||
| | |SAM F2 bit clear | ||
|- | |- | ||
|FFCB | |FFCB | ||
|VOFS3 | |VOFS3 | ||
|SAM | |SAM F2 set bit to add $800 to video offset | ||
|} | |} | ||
Revision as of 15:22, 4 May 2013
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 |
|---|---|---|
| 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 to add $200 to video offset |
| FFC8 | ||
| FFC9 | VOFS2 | SAM F1 set bit to add $400 to video offset |
| FFCA | SAM F2 bit clear | |
| FFCB | VOFS3 | SAM F2 set bit to add $800 to video offset |