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

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(So bit 3 does do something)
Line 3: Line 3:
 
'''Port Number:''' 1002
 
'''Port Number:''' 1002
  
'''Function:''' Unknown. This port definitely doesn't control RAM or flash wait states.
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'''Function:''' Memory-mapped flash chip size.
  
 
== Details ==
 
== Details ==
=== Bits [2:0] ===
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=== Bits [3:0] ===
Some values cause an instant crash unless interrupts are disabled and you are running in a RAM program; if you are running in a RAM program with interrupts disabled, no values cause a 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. 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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{|-
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|<u>Value</u>&nbsp;&nbsp;&nbsp;
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|<u>Effect</u>&nbsp;&nbsp;&nbsp;
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|-
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|0
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|Instant crash
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|-
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|1
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|Instant crash
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|-
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|2
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|Instant freeze
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|-
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|3
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|Crash upon return to OS
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|-
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|4
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|No crash, freezes if you do anything complicated in the OS
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|-
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|5
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|No crash, freezes if you do anything complicated in the OS
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|-
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|6
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|Normal value
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|-
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|7
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|No ill-effects apparent, does not appear to make OS noticeably slower
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|}
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=== Bit 3 ===
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Set this bit to crash.
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=== Bits [7:4] ===
 
=== Bits [7:4] ===
 
Writes have no apparent effect, value does not latch.
 
Writes have no apparent effect, value does not latch.

Revision as of 11:58, 5 April 2015

Synopsis

Port Number: 1002

Function: Memory-mapped flash chip size.

Details

Bits [3:0]

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.

Bits [7:4]

Writes have no apparent effect, value does not latch.