tmp89fm43l TOSHIBA Semiconductor CORPORATION, tmp89fm43l Datasheet - Page 34

• Manufacturer Part Number: tmp89fm43l
• Description: 8 Bit Microcontroller Tlcs-870/c1 Series
• Manufacturer: TOSHIBA Semiconductor CORPORATION

2.3
System clock controller
RB000
2.3.3.3
A quarter of the basic clock
for the low-frequency clock
SYSCR2<SYSCK>
SYSCR1<DV9CK>
peripheral circuits, from the gear clock (fcgck) or the clock that is a quarter of the low-frequency clock (fs).
The timing generator has the following functions:
Gear clock fcgck
(1)
The timing generator is a circuit that generates system clocks to be supplied to the CPU core and the
Timing generator
Note:Don't change CGCR<FCGCKSEL> in the SLOW mode. This may stop the gear clock (fcgck) from being
a machine cycle counter.
1. Generation of the main system clock (fm)
2. Generation of clocks for the timer counter, the time base timer and other peripheral circuits
changed.
The timing generator consists of a main system clock generator, a prescaler, a 21-stage divider and
Configuration of timing generator
1. Main system clock generator
2. Prescaler and divider
clock (fs) for the main system clock (fm) to operate the CPU core.
the clock that is a quarter of the low-frequency clock (fs).
clock is switched. If the currently operating oscillation circuit is stopped before the main system
clock is switched, the internal condition becomes as shown in Table 2-1 and a system clock
reset occurs. For details of clock switching, refer to "2.3.6 Operation Mode Control".
Figure 2-5 Configuration of Timing Generator
This circuit selects the gear clock (fcgck) or the clock that is a quarter of the low-frequency
Clearing SYSCR2<SYSCK> to "0" selects the gear clock (fcgck). Setting it to "1" selects
It takes a certain period of time after SYSCR2<SYSCK> is changed before the main system
Table 2-2 Gear Clock (fcgck)
Prescaler
CGCR<FCGCKSEL>
00
01
10
11
Divider
Timer counter, time base timer and other peripheral circuits
Main system clock generator
Page 20
Multiplexer
Reserved
A
B
fcgck
S
fc / 4
fc / 2
fc
Y
Main system clock
fm
Divider
Machine cycle counter
TMP89FM43L