Changes
8255
,* Mode 1 (Strobed Input/Output) and Mode 2 (Bi-Directional Bus), as far as I know, are not used by any program, Mode 0 (Basic Input/Output) is always used.
* NOTE- If you are using the firmware, always return the operating modes and I/O state of the ports used to their settings below. The firmware expects the settings to be the same as given below and may operate incorrectly if they are not.
Operating system settings:
* I/O Mode 0,
* Output For writing data to PSG all bits must be set to output,* for reading data from PSG all bits must be set to input (thereafter, output direction should be restored, for compatibility with the BIOS).
Operating system settings:
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Operating system settings:
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== PPI Control ==
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== Programming Examples ==
