Difference between revisions of "84PCE:Ports:5000"

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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.
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This port range has an interesting semi-pattern of read-only and latching ports. Some of these ports have a critical function for interrupt-handling. A partial list is below, but ports with some kind of function continue until at least 5055.
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This range is (probably?) memory-mapped to F00000.
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|<u>Port</u>&nbsp;&nbsp;&nbsp;
 
|<u>Port</u>&nbsp;&nbsp;&nbsp;

Revision as of 15:59, 30 March 2015

This port range has an interesting semi-pattern of read-only and latching ports. Some of these ports have a critical function for interrupt-handling. A partial list is below, but ports with some kind of function continue until at least 5055.

This range is (probably?) memory-mapped to F00000.

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
5015 00 ?? Read by the boot code at 001327h after power-off?
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