DS_1209F_004
73S1209F Data Sheet
KSTAT Register:
Enable HW Scanning
Enable Keypad Interrupt
Keypad
Initialization
All Column
Outputs = 0
Any
Row
Input = 0 ?
No
Yes
No
Deboucing
Timer
KSCAN Register:
Debouncing Time
Any Row
Input still = 0 ?
KSIZE Register:
Keypad Size Definition
KORDERL / H Registers:
Column Scan Order
Keypad Scanning
KSCAN Register:
Scanning Rate
How Many
keys have been
detected?
0 key
More
than
1 key
1 key
KCOL Register:
Value of the valid key column
Download of the key row and
column values in KROW and
KCOL registers
KROW Register:
Value of the valid key row
Keypad Interrupt
generation
KSTAT Register:
Key Detect Interrupt
No
Is (are)
the key(s)
released ?
(*)
Deboucing
Timer
Yes
No
KSCAN Register:
Debouncing Time
Register Used to Control the
hardware keypad interface
Is (are)
the key(s)
still released ?
(*)
Register written by the
hardware keypad interface
Yes
(*) Key release is cheked by looking for a low level on any row.
Figure 12: Keypad Interface Flow Chart
Rev. 1.2
63
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
