Maxim Integrated MAXQ7666 - Manual (Page 273)

8.3.4 Port Pin Examples
8.3.4.1 Port Pin Example 1: Driving Outputs on Port 0
move PO0, #000h ; Set all outputs low
move PD0, #0FFh ; Set all P0 pins to output mode
8.3.4.2 Port Pin Example 2: Receiving Inputs on Port 0
move PO0, #0FFh ; Set weak pullups ON on all pins
move PD0, #000h ; Set all P1 pins to input mode
nop ; Wait for external source to drive P1
move Acc, PI0 ; Get input values from P0
; (will return FF if no other source
; drives the pins low)
MAXQ7665/MAXQ7666 User’s Guide
Maxim Integrated