Datasheet

DS_1215F_003 73S1215F Data Sheet
Rev. 1.4 67
Figure 13: Keypad Interface Flow Chart
Any
Row
Input = 0 ?
Keypad
Initialization
All Column
Outputs = 0
Deboucing
Timer
Any Row
Input still = 0 ?
Yes
No
No
How Many
keys have been
detected?
Download of the key row and
column values in KROW and
KCOL registers
1 key
Keypad Interrupt
generation
Is (are)
the key(s)
released ?
(*)
Deboucing
Timer
Yes
Is (are)
the key(s)
still released ?
(*)
No
No
KSCAN Register:
Debouncing Time
KSTAT Register:
Enable HW Scanning
Enable Keypad Interrupt
Keypad Scanning
KORDERL / H Registers:
Column Scan Order
KSTAT Register:
Key Detect Interrupt
Yes
KCOL Register:
Value of the valid key column
KROW Register:
Value of the valid key row
KSCAN Register:
Scanning Rate
KSIZE Register:
Keypad Size Definition
0 key
Register Used to Control the
hardware keypad interface
Register written by the
hardware keypad interface
More
than
1 key
KSCAN Register:
Debouncing Time
(*) Key release is cheked by looking for a low level on any row.