84PCE:Ports:A000
From WikiTI
Revision as of 01:29, 31 March 2015 by MateoConLechuga (Talk | contribs)
Synopsis
Port Number: A000-A003
Memory-mapped address: F50000
Function: Set the mode of the keypad controller
Bits 0-1: Scan mode
- Mode 0: Idle.
- Mode 1: Indiscriminate key detection. Data registers are not updated, but whenever any key is pressed, interrupt bit 2 is set (and cannot be cleared until the key is released).
- Mode 2: Single scan. The keypad is scanned once, and then the mode returns to 0.
- Mode 3: Continuous scan. When scanning completes, it just starts over again after a delay.
Bits 2-15: Number of APB cycles to wait before scanning each row
Bits 16-31: Number of APB cycles to wait between scans
