TTP258
TonTouchTM
Preliminary
10 non-contact inputs touch pad detector
The touch pad detector applies the charge sharing conception. The inputs
share the pad with IO ports. Built-in charge sharing control, duty detector and
de-bounce feature can response the input with varied output refresh rate that
dependant on the system request. For power saving concern, auto power off
function and wake up de-bounce capability can support a lower average
operating current.
Modulation
OSCH/
clock selector
OSCL
Data Bus
Edge
Clock
CH0
Detector
Gating
CH1
:
12 bits Duty counter &
Reload data latch
TPCTF
:
:
:
Key scan & Timing control
CH8
CH9
TPCMPF
Touch pad selector
Touch available Pad
Figure: 10 keys Touch pad detector
Parameters
Touch pad OSC
Modulation clock
Duty counter
Target value
Remark
Using OSCH or OSCL
N=1,2,4,8,16,32,64,OSCL
With INT
4MHz or 16KHz (typ.)
OSCH/N or OSCL
12 bits
Reload data latch
Touch pads
12 bit
1~10 keys
Write only
Mask option
Key de-bounce time
Sensitivity level
s/w implements
Offset value by s/w
By application or cover thickness
Resolution=1 modulation clock
16’/04/06
Page 36 of 44
Ver.: 1.2
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