Difference between revisions of "84PCE:Ports:0009"
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(Add documentation on bit 4) |
(mention test points for bits 3 and 4 (info courtesy of Dmalenke)) |
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=== 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. | |
=== Bit [3] === | === Bit [3] === | ||
| − | Latches value written, no apparent effect. | + | Latches value written, no apparent effect. Connected to test point TP06A on rev. C - might be different on newer hardware revisions? |
=== Bit [4] === | === Bit [4] === | ||
| − | SPI slave select - reset to communicate with the LCD, set to communicate with the Python coprocessor. | + | 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] === | === 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.
