TC9256, 57APG/AFG

2006-07-14

9

The reference counter section consists of a crystal oscillator and a counter.

A crystal oscillator frequency of 3.6 MHz, 4.5 MHz, 7.2 MHz or 10.8 MHz can be selected. A maximum of 15

reference frequencies can be generated.

1.

Setting Reference Frequency

The reference frequency is set using bits R0 to R3.

Note 1: Reference frequencies marked with an asterisk “*” can only be generated with a 4.5 MHz crystal

oscillator.

Note 2: (*1) Standby mode

Standby mode occurs when bits R0, R1, R2 and R3 are all set to “1”. In standby mode, the

(pins at “L” level). This saves current consumption when the radio is turned off. The DO pins become

high impedance during standby mode.

During standby mode, the I/O ports (I/O-5 to I/O-9) and output ports (OT1 to OT4) can be controlled and

the crystal oscillator can be turned on and off.

Note 3: The system is set to standby mode when power is turned on. At this time, the crystal oscillator is not

oscillating and the I/O ports are set to input mode.