M16C28 Datasheet, PDF (64/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
7. Clock Generation Circuit
7. Clock Generation Circuit
The clock generation circuit contains four oscillator circuits as follows:
(1) Main clock oscillation circuit
(2) Sub clock oscillation circuit
(3) Variable on-chip oscillators
(4) PLL frequency synthesizer
Table 7.1 lists the clock generation circuit specifications. Figure 7.1 shows the clock generation circuit.
Figures 7.2 to 7.7 show the clock- associated registers.
Table 7.1 Clock Generation Circuit Specifications
Item
Use of clock
Clock frequency
Usable oscillator
Main Clock
Oscillation Circuit
Sub Clock
Oscillation Circuit
Variable On-chip Oscillator
PLL Frequency
Synthesizer
- CPU clock source - CPU clock source - CPU clock source
- CPU clock source
- Peripheral function - Timer A, B's clock - Peripheral function clock source - Peripheral function clock
clock source
source
- CPU and peripheral function
source
clock sources when the main
clock stops oscillating
0 to 20 MHz
32.768 kHz
Selectable source frequency:
f1(ROC), f2(ROC), f3(ROC)
Selectable divider:
by 2, by 4, by 8
10 to 20 MHz
- Ceramic oscillator - Crystal oscillator
- Crystal oscillator
Pins to connect XIN, XOUT
oscillator
XCIN, XCOUT
Oscillation stop, Available
restart function
Available
Oscillator status Oscillating
after reset
Stopped
Other
Externally derived clock can be input
Available
Oscillating
(CPU clock source)
Available
Stopped
Rev. 2.00 Jan. 31, 2007 ^{page 44} of 385
REJ09B0047-0200