Square-Wave Output Operation - NEC 78K0/KD1 Series User Manual

7.4.3 Square-wave output operation

A square wave with any selected frequency is output at intervals of the value preset to 8-bit timer compare register
5n (CR5n).
The TO5n pin output status is inverted at intervals of 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%).
[Setting]
<1> Set each register.
• Set the port latches (P17 and P33)
• 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.
<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 = f
CNT
(N: 00H to FFH, f
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.
Remark n = 0, 1
174
CHAPTER 7 8-BIT TIMER/EVENT COUNTERS 50 AND 51
Note
and port mode registers (PM17 and PM33)
LVS5n LVR5n
1 0 High-level output
0 1 Low-level output
Timer output F/F inversion enabled
Timer output enabled
(TMC5n = 00001011B or 00000111B)
/2 (N + 1)
: Count clock)
CNT
Preliminary User's Manual U16315EJ1V0UD
Timer Output F/F Status Setting
Note
to 0.