Datasheet

78K0/Kx2-L CHAPTER 7 8-BIT TIMER/EVENT COUNTERS 50 AND 51

R01UH0028EJ0400 Rev.4.00 329

Sep 27, 2010

7.4.3 Square-wave output operation

A square wave with any selected frequency is output at intervals determined by the value preset to 8-bit timer compare

The TO5n pin output status is inverted at intervals determined by the count value preset to CR5n by setting bit 0

(TOE5n) of 8-bit timer mode control register 5n (TMC5n) to 1. This enables a square wave with any selected frequency to

be output (duty = 50%).

Remark Square-wave output is operable only in the 78K0/KB2-L and 78K0/KC2-L.

Setting

<1> Set each register.

• Clear the port output latch (P17 or P33)

Note

and port mode register (PM17 or PM33)

Note

to 0.

• TCL5n: Select the count clock.

• CR5n: Compare value

• TMC5n: Stop the count operation, select the mode in which clear & start occurs on a match of TM5n and

CR5n.

LVS5n LVR5n Timer Output F/F Status Setting

0 1 Timer output F/F clear (0) (default value of TO5n output: low level)

1 0 Timer output F/F set (1) (default value of TO5n output: high level)

Timer output enabled

(TMC5n = 00001011B or 00000111B)

<2> After TCE5n = 1 is set, the count operation starts.

<3> The timer output F/F is inverted by a match of TM5n and CR5n. After INTTM5n is generated, TM5n is cleared to

00H.

<4> After these settings, the timer output F/F is inverted at the same interval and a square wave is output from TO5n.

The frequency is as follows.

• Frequency = 1/2t (N + 1)

(N: 00H to FFH)

Note 8-bit timer/event counter 50: P17, PM17

8-bit timer/event counter 51: P33, PM33

Caution Do not write other values to CR5n during operation.

Remarks 1. For how to enable the INTTM5n signal interrupt, refer to CHAPTER 17 INTERRUPT FUNCTIONS.

2. 78K0/KB2-L, 78K0/KC2-L: n = 0, 1