131
Clock Generator
Chapter 4
Preliminary User’s Manual U17566EE1V2UM00
(1)
CPU clocks
The CPU can be clocked directly by any of the oscillators, or by the output of
one of the PLLs.
The following table gives an overview of the available CPU clocks.
(2)
Peripheral clocks
The right-hand side of
Figure 4-1 on page 130
shows how the clocks for the
peripheral modules are generated and distributed.
PCLK clocks
The PCLK clocks supply following peripherals: the CAN Controllers CAN, the
UARTs, the Timers Z, the Watch Calibration Timer, and the Clocked Serial
Interfaces CSIB.
The clocks PCLK0…1 can be derived from the main oscillator or the PLL
output. The PCLK2…15 clocks are always derived from the main oscillator.
SPCLK clocks
The SPCLK clocks supply following peripherals: Stepper Motor Controller/
Driver, the Timer G, the Sound Generator, the Clocked Serial Interfaces CSIB,
the LCD Bus I/F and Controller/Driver, and A/D Converter ADC.
The clocks SPCLK0…1 can be derived from the main oscillator or the PLL.
The SPCLK2…15 clocks are always derived from the main oscillator.
IICLK clock
The clock IICLK for the I
2
C interface is supplied by the main oscillator or the
PLL.
(3)
Special clocks
The figure shows also some special clock signals. These are dedicated clocks
for the LCD Controller/Driver, Watch Timer, Watchdog Timer, and Watch
Table 4-1
Clock sources and frequencies for the CPU
Clock source
Frequency
Description
Ring osc
~240 KHz
Default clock source after reset release. Selectable as
clock source for Sub-WATCH mode release.
Sub osc
32 KHz
Selectable as clock source for Sub-WATCH mode
release.
Main osc
4 MHz
Always selected after power save mode release except
on Sub-WATCH mode release or default clock setting.
a
On Sub-WATCH mode release or default clock setting,
main or sub oscillator can be selected.
a)
See also
“CPU operation after power save mode release” on page 181
PLL
16 MHz
f
main
×
4 can be selected for CPU clock supply.
32 MHz
f
main
×
8 can be selected for CPU clock supply.
SSCG
8 MHz
f
main
×
12/6
b
can be selected for CPU clock supply.
b)
Multiplication is performed by the SSCG, the division by the SSCG post scaler.
16 MHz
f
main
×
16/4
b
can be selected for CPU clock supply.
24 MHz
f
main
×
12/2
b
can be selected for CPU clock supply.
32 MHz
f
main
×
16/2
b
can be selected for CPU clock supply.
48 MHz
f
main
×
12/1
b
can be selected for CPU clock supply.
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