NEC PD78055 Benutzerhandbuch

NEC

238

CHAPTER 9 8-BIT TIMER/EVENT COUNTERS 1 AND 2

Figure 9-13. Square-Wave Output Operation Timing

Note

The initial value of TO2 pin output can be set with the bits 6 and 7 (LVR2, LVS2) of 8-bit timer output control

register (TOC1).

9.5 Cautions on 8-Bit Timer/Event Counters 1 and 2

(1) Timer start errors

An error with a maximum of one clock may occur concerning the time required for a match signal to be

generated after timer start. This is because 8-bit timer registers 1 and 2 (TM1 and TM2) starts asynchronously

with the count pulse.

Figure 9-14. 8-Bit Timer Registers 1 and 2 Start Timing

Count Clock

TM1, TM2 Count Value

CR10, CR20

INTTM2

TO2 Pin Output

Note

0000

0001

0002

N-1

N

0000

0001

0002

N-1

N

0000

N

Count Pulse

TM1, TM2 Count Value

00H

01H

02H

03H

04H

Timer Start