Difference between revisions of "84PCE:Ports:5000"
From WikiTI
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[[Category:84PCE:Ports:By_Address|5000 Range Unknowns]] [[Category:84PCE:Ports:By_Name|5000 Range Unknowns]] [[Category:84PCE:Ports:Unknown|5000 Range Unknowns]] | [[Category:84PCE:Ports:By_Address|5000 Range Unknowns]] [[Category:84PCE:Ports:By_Name|5000 Range Unknowns]] [[Category:84PCE:Ports:Unknown|5000 Range Unknowns]] | ||
| − | + | This port range has an interesting semi-pattern of read-only and latching ports. A partial list is below, but ports with some kind of function continue until at least 5055. | |
{|- | {|- | ||
|<u>Port</u> | |<u>Port</u> | ||
| Line 61: | Line 61: | ||
| | | | ||
|''Port 500F may always read zero'' | |''Port 500F may always read zero'' | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5010|5010]] | ||
| + | |00 | ||
| + | |FF | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5011|5011]] | ||
| + | |00 | ||
| + | |FF | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5012|5012]] | ||
| + | |00 | ||
| + | |3F | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |5013 | ||
| + | |00 | ||
| + | |?? | ||
| + | |''Ports 5013-5020 may always read zero'' | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5021|5021]] | ||
| + | |90 | ||
| + | |?? | ||
| + | |Bit 3 is set when a key is held | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5022|5022]] | ||
| + | |08 | ||
| + | |?? | ||
| + | |Writes do not change value | ||
| + | |- | ||
| + | |5023 | ||
| + | |00 | ||
| + | |?? | ||
| + | |''Port 5023 may always read zero'' | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5024|5024]] | ||
| + | |00 | ||
| + | |FF | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5025|5025]] | ||
| + | |00 | ||
| + | |FF | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |[[:84PCE:Ports:5026|5026]] | ||
| + | |00 | ||
| + | |3F | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |5027 | ||
| + | |00 | ||
| + | |?? | ||
| + | |''Ports 5027-502B may always read zero'' | ||
| + | |- | ||
| + | |[[:84PCE:Ports:502C|502C]] | ||
| + | |00 | ||
| + | |FF | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |[[:84PCE:Ports:502C|502D]] | ||
| + | |00 | ||
| + | |FF | ||
| + | |Latches value written | ||
| + | |- | ||
| + | |[[:84PCE:Ports:502C|502E]] | ||
| + | |00 | ||
| + | |3F | ||
| + | |Latches value written | ||
|- | |- | ||
|} | |} | ||
Revision as of 22:05, 27 March 2015
This port range has an interesting semi-pattern of read-only and latching ports. A partial list is below, but ports with some kind of function continue until at least 5055.
| Port | Default | Bits | Information |
| 5000 | 00 | ?? | May or may not serve a purpose? |
| 5001 | 80 | ?? | Bit 2 is set while any key is being pressed |
| 5002 | 00 | ?? | Ports 5002-5003 may always read zero |
| 5004 | 11 | FF | Reset bit 4 to freeze |
| 5005 | 30 | FF | Setting bit 2 or bit 7 (or both) will freeze the calculator |
| 5006 | 00 | 3F | Latches value written |
| 5007 | 00 | Ports 5007-500B may always read zero | |
| 500C | 19 | FF | Reset bit 4 to freeze |
| 500D | 00 | FF | Latches value written |
| 500E | 00 | 3F | Latches value written |
| 500F | 00 | Port 500F may always read zero | |
| 5010 | 00 | FF | Latches value written |
| 5011 | 00 | FF | Latches value written |
| 5012 | 00 | 3F | Latches value written |
| 5013 | 00 | ?? | Ports 5013-5020 may always read zero |
| 5021 | 90 | ?? | Bit 3 is set when a key is held |
| 5022 | 08 | ?? | Writes do not change value |
| 5023 | 00 | ?? | Port 5023 may always read zero |
| 5024 | 00 | FF | Latches value written |
| 5025 | 00 | FF | Latches value written |
| 5026 | 00 | 3F | Latches value written |
| 5027 | 00 | ?? | Ports 5027-502B may always read zero |
| 502C | 00 | FF | Latches value written |
| 502D | 00 | FF | Latches value written |
| 502E | 00 | 3F | Latches value written |
