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TMP86FS49FG

2.2.1 Clock Generator

The clock generator generates the basic clock which provides the system clocks supplied to the CPU core

and peripheral hardware. It contains two oscillation circuits: One for the high-frequency clock and one for the

low-frequency clock. Power consumption can be reduced by switching of the standby controller to low-power

operation based on the low-frequency clock.

The high-frequency (fc) clocks and low-frequency (fs) clock can easily be obtained by connecting a resona-

tor between the XIN/XOUT and XTIN/XTOUT pins respectively. Clock input from an external oscillator is

also possible. In this case, external clock is applied to XIN/XTIN pin with XOUT/XTOUT pin not connected.

Figure 2-3 Examples of Resonator Connection

Note:The function to monitor the basic clock directly at external is not provided for hardware, however, with dis-

abling all interrupts and watchdog timers, the oscillation frequency can be adjusted by monitoring the pulse

which the fixed frequency is outputted to the port by the program.

The system to require the adjustment of the oscillation frequency should create the program for the adjust-

ment in advance.

2.2.2 Timing Generator

The timing generator generates the various system clocks supplied to the CPU core and peripheral hardware

from the basic clock (fc or fs). The timing generator provides the following functions.

1. Generation of main system clock

3. Generation of source clocks for time base timer

4. Generation of source clocks for watchdog timer

5. Generation of internal source clocks for timer/counters

6. Generation of warm-up clocks for releasing STOP mode

2.2.2.1 Configuration of timing generator

The timing generator consists of a 2-stage prescaler, a 21-stage divider, a main system clock generator,

and machine cycle counters.

An input clock to the 7th stage of the divider depends on the operating mode, DV7CK (Bit4 in

TBTCR), that is shown in Figure 1-5. As reset and STOP mode started/canceled, the prescaler and the

divider are cleared to “0”.

XOUT

XIN

(Open)

XOUT

XIN

XTOUT

XTIN

(Open)

XTOUT

XTIN

(a) Crystal/Ceramic

resonator

(b) External oscillator

(c) Crystal

(d) External oscillator

High-frequency clock

Low-frequency clock

TENTATIVE