TTP258
TonTouchTM
Preliminary
§ System function description:
S-1: System Oscillator
The high-speed oscillator is operated in built-in RC mode. Built-in RC
oscillator is fixed 4MHz
S-2: Peripheral Oscillator
The low speed oscillator was built-in an internal RC oscillator that is for low
power consumption consideration and fixed peripheral device timing control.
Built-in RC oscillator and the frequency range between 12 KHz ~ 21 KHz.
S-3: CPU clock
The CPU clock comes from system/peripheral oscillator which was controlled
by H/L bit in PS register. In the normal operation, the system clock comes from
high-speed system oscillator (OSCH/2). The low speed operation frequency
(OSCL/2) comes from RC oscillator.
OSCEN
OSCH
RC oscillator
Figure: System High Speed Oscillator
1
M
U
X
OSC
CPU machine
/2
0
H/L
16K Hz (Built-in RC)
Peripheral clock OSCL (16K Hz)
TBCK
Figure: System Oscillator & CPU Clock Sources
16’/04/06
Page 11 of 44
Ver.: 1.2
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