MediaWiki:Sitenotice:
2024-03-02: The wiki ran out of disk space, so things were not working. This has been resolved by adding another 5GB of quota ;-) Thanks to Tim Lindner for reporting the issues. 2020-05-17: If a page gives you an error about some revision not being found, just EDIT the page and the old page should appear in the editor. If it does, just SAVE that and the page should be restored. OS-9 Al (talk) 12:22, 17 May 2020 (CDT)

SAM: Difference between revisions

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|FFC9
|FFC9
|VOFS2
|F1SET
|SAM F1 set bit to add $400 to video offset
|SAM F1 set bit to add $400 to video offset
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|-  
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|-  
|FFCB
|FFCB
|VOFS3
|F2SET
|SAM F2 set bit to add $800 to video offset  
|SAM F2 set bit to add $800 to video offset  
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|FFCC
|
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|-
|FFCD
|
|
|}
|}



Revision as of 19:40, 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 F1SET SAM F1 set bit to add $400 to video offset
FFCA SAM F2 bit clear
FFCB F2SET SAM F2 set bit to add $800 to video offset
FFCC
FFCD