Square Wave Output Operation - NEC mPD78F0730 Preliminary User's Manual

6.4.2 Square wave output operation

When 16-bit timer/event counter 00 operates as an interval timer (see 6.4.1), a square wave can be output from the
TO00 pin by setting the 16-bit timer output control register 00 (TOC00) to 03H.
When TMC003 and TMC002 are set to 11 (count clear & start mode entered upon a match between TM00 and
CR000), the counting operation is started in synchronization with the count clock.
When the value of TM00 later matches the value of CR000, TM00 is cleared to 0000H, an interrupt signal
(INTTM000) is generated, and output of the TO00 pin is inverted. This TO00 pin output that is inverted at fixed
intervals enables TO00 to output a square wave.
Remarks 1. For the setting of I/O pins, see 6.3 (6) Port mode register 0 (PM0).
2. For how to enable the INTTM000 signal interrupt, see CHAPTER 13 INTERRUPT FUNCTIONS.
Count clock
(TMC003, TMC002)
Compare register
Compare match interrupt
128
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CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Figure 6-15. Block Diagram of Square Wave Output Operation
Operable bits
TMC003, TMC002
Figure 6-16. Basic Timing Example of Square Wave Output Operation
TM00 register
0000H
Operable bits
00
(CR000)
TO00 pin output
(INTTM000)
Interval
(N + 1)
Preliminary User's Manual U19014EJ1V0UD
Clear
16-bit counter (TM00)
Match signal
CR000 register
N N
11
N
Interval Interval
(N + 1) (N + 1)
Output
TO00 pin
controller
INTTM000 signal
N N
Interval
(N + 1)