Difference between revisions of "84PCE:Ports:1002"

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[[Category:84PCE:Ports:By_Address|1002 - Unknown]] [[Category:84PCE:Ports:By_Name|Unknown port 1005]]
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[[Category:84PCE:Ports:By_Address|1002 - Flash chip size]] [[Category:84PCE:Ports:By_Name|Flash chip size]]
 
== Synopsis ==
 
== Synopsis ==
 
'''Port Number:''' 1002
 
'''Port Number:''' 1002
  
'''Function:''' Memory-mapped flash chip size.
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'''Function:''' Memory-mapped flash chip size. This port is only applicable to older devices which feature a [[84PCE:Ports:1000|parallel flash chip.]]
  
 
== Details ==
 
== Details ==
=== Bits [3:0] ===
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=== Bits [2:0] ===
Sets the flash chip size. 06 is the default (4 MB). 07 will map 8 MB, which will cause the 4 MB to be mirrored twice. 08 will attempt to map 16 MB, which has unknown effects but generally causes an instant crash. Smaller values map less flash, and will generally cause the OS to eventually freeze or crash.
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Sets the flash chip size. 06 is the default (4 MB). 07 will map 8 MB, which will cause the 4 MB to be mirrored twice. Smaller values map less flash, possibly down to 64 K.
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=== Bit 3 ===
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When this bit is set, the flash mapping is forced to 64KB (the equivalent of a 0 in bits 0-2).
  
 
=== Bits [7:4] ===
 
=== Bits [7:4] ===
 
Writes have no apparent effect, value does not latch.
 
Writes have no apparent effect, value does not latch.

Latest revision as of 07:22, 18 April 2020

Synopsis

Port Number: 1002

Function: Memory-mapped flash chip size. This port is only applicable to older devices which feature a parallel flash chip.

Details

Bits [2:0]

Sets the flash chip size. 06 is the default (4 MB). 07 will map 8 MB, which will cause the 4 MB to be mirrored twice. Smaller values map less flash, possibly down to 64 K.

Bit 3

When this bit is set, the flash mapping is forced to 64KB (the equivalent of a 0 in bits 0-2).

Bits [7:4]

Writes have no apparent effect, value does not latch.