Difference between revisions of "84PCE:Ports:1002"
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(So now we know this is the flash chip size.) |
(Notice of applicability) |
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| − | [[Category:84PCE:Ports:By_Address|1002 - | + | [[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. | + | '''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 [ | + | === 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 | + | 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] === | === 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.
