Changes
8255
,The PPI is selected when bit 11 of the I/O port address is set to "0", bits 9 and 8 then define the PPI function access as shown below:
{|{{Prettytable|width: 700px; font-size: 2em;}}
|''Bit 9''||''Bit 8''||''Description''||''Read/Write status''
|-
|0||0||Port A Data||Read/Write
|-
|0||1||Port B Data||Read/Write
|-
|1||0||Port C Data||Read/Write
|-
|1||1||Control||Write Only
|-
|}