Difference between revisions of "84PCE:Ports:1005"

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(The text needs to be less certain-sounding.)
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[[Category:84PCE:Ports:By_Address|1005 - VRAM Wait States?]] [[Category:84PCE:Ports:By_Name|VRAM Wait States?]]
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[[Category:84PCE:Ports:By_Address|1005 - Flash Wait States]] [[Category:84PCE:Ports:By_Name|Flash Wait States]]
 
== Synopsis ==
 
== Synopsis ==
 
'''Port Number:''' 1005
 
'''Port Number:''' 1005
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'''Memory-mapped Address:''' E00005
 
'''Memory-mapped Address:''' E00005
  
'''Function:''' Possibly controls wait states to VRAM accesses. Or maybe flash wait states. Or maybe we have no control over any wait states whatsoever.
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'''Function:''' Controls flash wait states. Each read from flash will have at least 6 wait states, plus the number of wait states specified in this port. The OS defaults to 04 in this port, so by default, every read from flash incurs a 10 wait state penalty. (V/RAM gets 4 wait states.)
  
 
== Details ==
 
== Details ==
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|-
 
|-
 
|00
 
|00
|Instant hard crash & reset
+
|Instant hard crash & reset if OS ISR is enabled
 
|-
 
|-
 
|01
 
|01
|Makes OS a little (? 40 %) faster for some operations
+
|Makes OS a little faster, perhaps 30 %
 
|-
 
|-
 
|02-03
 
|02-03

Revision as of 00:51, 3 April 2015

Synopsis

Port Number: 1005

Memory-mapped Address: E00005

Function: Controls flash wait states. Each read from flash will have at least 6 wait states, plus the number of wait states specified in this port. The OS defaults to 04 in this port, so by default, every read from flash incurs a 10 wait state penalty. (V/RAM gets 4 wait states.)

Details

Value    Effect   
00 Instant hard crash & reset if OS ISR is enabled
01 Makes OS a little faster, perhaps 30 %
02-03 No ill-effects
04 Normal value
10 OS feels noticeably sluggish
20 OS is unbearably sluggish, RAM program dummy loop is not slower
FF Don't even bother trying to do anything