TTP258
TonTouchTM
Preliminary
I/O Port with external input
The input/output port has the I/O control register for switching input or
output mode and output data register stores the output data in output mode. If
control register=1 and output data=1, the I/O port is programmed as input
with pull-up resistor and also actives the wake-up function. User intends to read
the port data with differed read instruction. The read PI is reading data comes
from PAD input data. The data register reading result will have the same value
with output register data. Software can performs a configuration (data=0,
changing the control 0 or 1) for open drain type that specifies suitable for key
scan application. An additional feature supports the interrupt input triggers and
Timer external clock sources.
I/O control Data Output data Pull-up R Wake-up feature External inputs
0
X
0
1
No
No
Enable
No
No
Enable
No
Enable
Enable
1
1
X: don’t care the value
I/O control Data
MODE
Output mode
Input mode
PAD
0
1
Output Register data
Input data
Read PI
Read Input Data
Output Register data
PAD input data
0
1
Pull-up R
P
Data Bus
S
D
Q
CK QB
I/O control Register Write
PR
S
P
D
Q
PAD
Output Data Register Write
Read PI
CK QB
N
M
U
X
0
1
Read
Wake-up
N
N
Timer/counter external clock
External interrupt
Figure IO-A: Standard IO Port with wake-up/interrupt/timer clock inputs
16’/04/06
Page 28 of 44
Ver.: 1.2
TTELEC [ TT Electronics ]
