
CHAPTER 6 CLOCK GENERATION FUNCTION
Preliminary User’s Manual U16895EJ1V0UD
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(1) Main clock oscillator
The main clock oscillator oscillates the following frequencies (fX).
fX = 2 MHz (REGC = VDD = 2.7 to 5.5 V, in PLL mode)
fX = 2 to 5 MHz (REGC = VDD = 4.5 to 5.5 V, in PLL mode)
fX = 2 to 8Note MHz (REGC = VDD = 2.7 to 5.5 V, in clock-through mode)
Note This value may change after evaluation.
(2) Subclock oscillator
The subclock oscillator oscillates a frequency of 32.768 kHz (fXT).
(3) Main clock oscillator stop control
This circuit generates a control signal that stops oscillation of the main clock oscillator.
Oscillation of the main clock oscillator is stopped in the STOP mode or when the PCC.MCK bit = 1 (valid only
when the PCC.CLS bit = 1).
(4) Prescaler 1
This prescaler generates the clock (fXX to fXX/1024) to be supplied to the following on-chip peripheral functions:
TMP0, TM00, TM01, TM50, TM51, TMH0, TMH1, CSI00, CSI01, CSIA0, UART0, UART1, I
2C0, and ADC
(5) Prescaler 2
This circuit divides the main clock (fXX).
The clock generated by prescaler 2 (fXX to fXX/32) is supplied to the selector that generates the CPU clock
(fCPU) and internal system clock (fCLK).
fCLK is the clock supplied to the INTC, ROM correction, ROM, and RAM blocks, and can be output from the
CLKOUT pin.
(6) Interval timer BRG
This circuit divides the clock (fX) generated by the main clock oscillator to a specific frequency (32.768 kHz)
and supplies that clock to the watch timer block. It can also be used as an interval timer.
For details, refer to CHAPTER 11 INTERVAL TIMER, WATCH TIMER.
(7) PLL
This circuit multiplies the clock (fX) generated by the main clock oscillator.
It operates in two modes: clock-through mode in which fX is output as is, and PLL mode in which a multiplied
clock is output. These modes can be selected by using the PLLCTL.SELPLL bit.
Operation of the PLL can be started or stopped by the PLLCTL.PLLON bit.
(8) Ring-OSC (on-chip ring oscillator)
The Ring-OSC oscillator oscillates a frequency (fR) of 120 to 480 kHz (240 kHz (TYP.)).