Difference between revisions of "84PCE:Ports:0000 Unknowns"

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[[Category:84PCE:Ports:By_Address|0000 Unknowns]] [[Category:84PCE:Ports:By_Name|0000 Unknowns]] [[Category:84PCE:Ports:Unknown|0000 Unknowns]]
 
  
If a port is not listed; it indicates that writes have no effect and do not latch, and that reads are 0. Note that this may not be true one hundred percent.
 
 
=== 0000 Range ===
 
{|-
 
|<u>Port</u>&nbsp;&nbsp;&nbsp;
 
|<u>Default</u>&nbsp;&nbsp;&nbsp;
 
|<u>Bits</u>&nbsp;&nbsp;&nbsp;
 
|<u>Information</u>&nbsp;&nbsp;&nbsp;
 
|-
 
|[[:84PCE:Ports:0000|0000]]
 
|03
 
|D3
 
|CPU Speed Control
 
|-
 
|[[:84PCE:Ports:0001|0001]]
 
|03
 
|13
 
|OS Timer Control
 
|-
 
|[[:84PCE:Ports:0002|0002]]
 
|
 
|??
 
|Read only, value can change
 
|-
 
|[[:84PCE:Ports:0005|0005]]
 
|76
 
|??
 
|Set bit 5 to freeze, bit 6 affects backlight
 
|-
 
|[[:84PCE:Ports:0006|0006]]
 
|03
 
|03?
 
|Display refresh
 
|-
 
|[[:84PCE:Ports:0007|0007]]
 
|B7
 
|FF
 
|Latches values written
 
|-
 
|[[:84PCE:Ports:0008|0008]]
 
|7F
 
|??
 
|Cannot change value
 
|-
 
|[[:84PCE:Ports:0009|0009]]
 
|
 
|??
 
|Appears to be a part of the power control system.
 
|-
 
|[[:84PCE:Ports:000A|000A]]
 
|05
 
|??
 
|Latches value written, OS reset to 05
 
|-
 
|[[:84PCE:Ports:000B|000B]]
 
|FC
 
|??
 
|Cannot change value
 
|-
 
|[[:84PCE:Ports:000C|000C]]
 
|00
 
|FF
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:000D|000D]]
 
|FF
 
|FF
 
|Bit 0: Freeze if reset<br />Bit 1: Crash if reset<br />Bit 2: No apparent effect if reset<br />Bit 3: Reset to disable VRAM? Upon set, VRAM is garbage.<br />Bits [7:4]Possibly last value written
 
|-
 
|[[:84PCE:Ports:000E|000E]]
 
|0A
 
|FF
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:000F|000F]]
 
|42
 
|?3
 
|High nibble may be a status, low 2 bits latch value written
 
|-
 
|[[:84PCE:Ports:001C|001C]]
 
|80
 
|??
 
|Cannot change value
 
|-
 
|[[:84PCE:Ports:0028|0028]]
 
|
 
|FD
 
|Bit 1 is always 0, other bits latch value written
 
|-
 
|[[:84PCE:Ports:0029|0029]]
 
|00
 
|01
 
|Bit 0 latches value written
 
|-
 
|[[:84PCE:Ports:002A|002A]]
 
|70
 
|73
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:002B|002B]]
 
|FE
 
|FF
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:002C|002C]]
 
|
 
|FF
 
|Ports 002C-0031 latch value written
 
|-
 
|[[:84PCE:Ports:0032|0032]]
 
|
 
|07
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:0033|0033]]
 
|
 
|F1
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:0034|0034]]
 
|
 
|31
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:0035|0035]]
 
|
 
|3F
 
|Latches value written
 
|-
 
|[[:84PCE:Ports:0036|0036]]
 
|
 
|FF
 
|Ports 0036-0039 latch value written
 
|-
 
|}
 

Latest revision as of 03:06, 6 August 2017