I/O Expansion Block
PA[7:0] 2mA Totem pole outputs.
bit and byte addressable.
PB[3:0] 4mA Totem pole outputs. Power up to high.
PB[7:4] 4mA Open drain outputs.
OEA# Port A output enable. Internal weak pull up.
PC[7:4] Inputs with internal weak pull up*
PC[3:0] Inputs with internal weak pull down
PD[7:0] Bi-directional I/O port
byte addressable only. Power up to input mode.
* Pull-up/down resistors are typically 50K ohms.