4501 datasheet(169/212 Pages) RENESAS

169 / 212 page

2.8 Oscillation circuit

2-52

Rev.2.01

Feb 07, 2005

4501 Group

APPLICATION

REJ09B0192-0201

2.8.3 Notes on use

(1)

Clock control

Execute the CMCK or the CRCK instruction in the initial setting routine of program (executing it in

address 0 in page 0 is recommended).

The oscillation circuit by the CMCK or CRCK instruction can be selected only at once. The oscillation

circuit corresponding to the first executed one of these two instructions is valid. Other oscillation

circuits and the on-chip oscillator stop.

(2)

On-chip oscillator

The clock frequency of the on-chip oscillator depends on the supply voltage and the operation

temperature range.

Be careful that variable frequencies when designing application products.

Also, the oscillation stabilize wait time after system is released from reset is generated by the on-

chip oscillator clock. When considering the oscillation stabilize wait time after system is released

from reset, be careful that the variable frequency of the on-chip oscillator clock.

(3)

External clock

When the external signal clock is used as the source oscillation (f(XIN)), note that the RAM back-up

mode (POF and POF2 instructions) cannot be used.

(4)

Value of a part connected to an oscillator

Values of a capacitor and a resistor of the oscillation circuit depend on the connected oscillator and

the board. Accordingly, consult the oscillator manufacturer for values of each part connected the

oscillator.

4501 Datasheet(PDF) 169 Page - Renesas Technology Corp