Renesas 16-bit single-chip microcomputer Manuel D’Utilisation

Rev.1.02    Jul 01, 2005    page 97 of 314
REJ09B0126-0102

M16C/6N Group (M16C/6NL, M16C/6NN)

12. Timers

This document is under development and its contents are subject to change.

Item

         Specification

Count Source

 • Two-phase pulse signals input to TAiIN or TAiOUT pins

Count Operation

 • Up-count or down-count can be selected by two-phase pulse signal

 • When the timer overflows or underflows, it reloads the reload register

contents and continues counting. When operating in free-running mode,

the timer continues counting without reloading.

Divide Ratio

1/ (FFFFh - n + 1) for up-count

1/ (n + 1) for down-count

n : set value of the TAi register   0000h to FFFFh

Count Start Condition

Set the TAiS bit in the TABSR register to “1” (start counting)

Count Stop Condition

Set the TAiS bit to “0” (stop counting)

Interrupt Request Generation Timing Timer overflow or underflow

TAiIN Pin Function

Two-phase pulse input

TAiOUT Pin Function

Two-phase pulse input

Read from Timer

Count value can be read by reading the TAi register

Write to Timer

 • When not counting and until the 1st count source is input after counting start

Value written to TAi register is written to both reload register and counter

 • When counting (after 1st count source input)

Value written to TAi register is written to reload register

(Transferred to counter when reloaded next)

Select Function 

(1)

 • Normal processing operation (timer A2 and timer A3)

The timer counts up rising edges or counts down falling edges on TAjIN

pin when input signals on TAjOUT pin is “H”.

 • Counter initialization by Z-phase input (timer A3)

The timer count value is initialized to “0” by Z-phase input.

Up-
count

Up- 
count

Up- 
count

Down- 
count

Down- 
count

Down- 
count

TAjOUT

TAjIN

Count up all edges

Count up all edges

Count down all edges

Count down all edges

TAkOUT

TAkIN

 • Multiply-by-4 processing operation (timer A3 and timer A4)

If the phase relationship is such that TAkIN pin goes “H” when the input

signal on TAkOUT pin is “H”, the timer counts up rising and falling edges

on TAkOUT and TAkIN pins.  If the phase relationship is such that TAkIN

pin goes “L” when the input signal on TAkOUT pin is “H”, the timer counts

down rising and falling edges on TAkOUT and TAkIN pins.

i = 2 to 4

j = 2, 3

k = 3, 4

NOTE:

1. Only timer A3 is selectable. Timer A2 is fixed to normal processing operation, and timer A4 is fixed

to multiply-by-4 processing operation.