NO:
W90P710 Programming Guide
VERSION:
2.0
PAGE:
222
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed, distributed or reproduced without permission
from Winbond.
Table No.: 2005-W90P710-11-A
20 Keypad Interface
20.1 Overview
W90P710 Keypad Interface (
KPI
) is an APB slave with 4-row scan output and 8-column scan
input. KPI scans an array up to 16x8 with an external 4 to 16 decoder. It can also be programmed to
scan 8x8 or 4x8 key array. If the 4x8 array is selected then external decoder is not necessary
because the scan signals are derived by W90P710 itself. Any 1 or 2 keys in the array that pressed are
debounced and encoded. If more than 2 keys are pressed, only the keys or apparent keys in the array
with the lowest address will be decoded.
KPI supports 2-keys scan interrupt and specified 3-keys interrupt or chip reset. If the 3 pressed
keys matches with the 3 keys defined in
KPI3KCONF
, it will generate an interrupt or chip reset to
nWDOG reset output depend on the
ENRST
setting. The interrupt is generated whenever the scanner
detects a key is pressed. The interrupt conditions are 1 key, or 2 keys.
W90P710 provides two keypad connecting interface. One is allocated in LCD (GPIO30-41)
interface, the other is in Ethernet RMII PHY interface and I2C interface 2 SDA1, SCL1 (GPIO42-51).
Software should set KPSEL bit in
KPICONF
register to decide which interface is used as keypad
connection port.
The keypad interface has the following features:
z
maximum 16x8 array
z
programmable debounce time
z
low-power wakeup mode
z
programmable three-key reset
