Difference between revisions of "84PCE:Ports:0009"
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(mention test points for bits 3 and 4 (info courtesy of Dmalenke)) |
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| − | [[Category:84PCE:Ports:By_Address|0009 - | + | [[Category:84PCE:Ports:By_Address|0009 - GPIO A OUT]] [[Category:84PCE:Ports:By_Name|GPIO A OUT]] |
== Synopsis == | == Synopsis == | ||
'''Port Number:''' 0009 | '''Port Number:''' 0009 | ||
| − | '''Function:''' | + | '''Function:''' GPIO A Output |
== Details == | == Details == | ||
| − | + | These GPIOs appear to be connected to power control. | |
=== Bits [1:0] === | === Bits [1:0] === | ||
| Line 13: | Line 13: | ||
=== Bit [2] === | === Bit [2] === | ||
| − | + | Likely connected to the LCD's reset line, which is active low. After being set, the LCD must be given a sequence of initialization commands before it can display an image again. | |
| − | === Bits [7: | + | === Bit [3] === |
| + | Latches value written, no apparent effect. Connected to test point TP06A on rev. C - might be different on newer hardware revisions? | ||
| + | |||
| + | === Bit [4] === | ||
| + | SPI slave select - reset to communicate with the LCD, set to communicate with the Python coprocessor. Connected to test point TP09A on rev. C - might be different on newer hardware revisions? | ||
| + | |||
| + | === Bits [7:5] === | ||
Latches value written, no apparent effect. | Latches value written, no apparent effect. | ||
Latest revision as of 13:48, 22 August 2022
Synopsis
Port Number: 0009
Function: GPIO A Output
Details
These GPIOs appear to be connected to power control.
Bits [1:0]
Latches value written, no apparent effect.
Bit [2]
Likely connected to the LCD's reset line, which is active low. After being set, the LCD must be given a sequence of initialization commands before it can display an image again.
Bit [3]
Latches value written, no apparent effect. Connected to test point TP06A on rev. C - might be different on newer hardware revisions?
Bit [4]
SPI slave select - reset to communicate with the LCD, set to communicate with the Python coprocessor. Connected to test point TP09A on rev. C - might be different on newer hardware revisions?
Bits [7:5]
Latches value written, no apparent effect.
