Changes

8255

98 bytes added, 12:11, 26 January 2010
* 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.
=== Port Usage ===
* 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.
* 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.  === PPI Port A ===
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).
==== NOTE ==== * For writing data to Bit7-0 : [[PSG all bits must be set to output,* for reading data from PSG all bits must be set to input. ]] databus
=== PPI Port B ===
Operating system settings:
|}
=== PPI Port C ===
Operating system settings:
|-
|}
 
== PPI Control ==
 
...
== Programming Examples ==
6,388
edits