Renesas 6NM User Manual

Rev.1.10    Jul 01, 2005    page 94 of 318
REJ09B0124-0110

M16C/6N Group (M16C/6NK, M16C/6NM)

12. Timers

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

Figure 12.3 shows a block diagram of the timer A. Figures 12.4 to 12.6 show the timer A-related registers.

The timer A supports the following four modes. Except in event counter mode, timers A0 to A4 all have the

same function. Use the TMOD1 to TMOD0 bits in the TAiMR register (i = 0 to 4) to select the desired mode.

• Timer mode:

The timer counts an internal count source.

• Event counter mode:

The timer counts pulses from an external device or overflows and

underflows of other timers.

• One-shot timer mode:

The timer outputs a pulse only once before it reaches the minimum count “0000h.”

• Pulse width modulation mode: The timer outputs pulses in a given width successively.

TCK1 to TCK0, TMOD1 to TMOD0, MR2 to MR1: Bits in TAiMR register
TAiTGH to TAiTGL: Bits in ONSF register If i = 0, bits in TRGSR register if i = 1 to 4
TAiS: Bit in TABSR register
TAiUD: Bit in UDF register

i = 0 to 4
j = i - 1except j = 4 when i = 0
k = i + 1 except k = 0 when i = 4

NOTE:

1. Overflow or underflow

00
01
10
11

TCK1 to TCK0

Select Clock source

TAiIN

Select clock

f1 or f2

f8

f32

fC32

Timer

: TMOD1 to TMOD0 = 00, MR2 = 0

One shot

: TMOD1 to TMOD0 = 10

Pulse width modulation : TMOD1 to TMOD0 = 11

Timer (gate function)

: TMOD1 to TMOD0 = 00, MR2 = 1

Event counter 

: TMOD1 to TMOD0 = 01

TMOD1 to TMOD0, 
MR2

00
01
10
11

TAiTGH to TAiTGL

TB2 overflow (1)

TAj overflow (1)

TAk overflow (1)

00
10
11

01

TMOD1 to TMOD0

Polarity

selection

To external trigger circuit

Pulse output

Decrement

0

1

MR2

TAiS

TAiUD

TAiOUT

High-order Bits of Data Bus

Low-order Bits of Data Bus 

Reload Register

Low-order
8 bits

High-order
8 bits

Counter

     Increment/Decrement
Always counts down except
in event counter mode

Toggle Flip-Flop

TAi

Addresses

TAj

TAk

Timer A0

0387h - 0386h

Timer A4

Timer A1

Timer A1

0389h - 0388h

Timer A0

Timer A2

Timer A2

038Bh- 038Ah

Timer A1

Timer A3

Timer A3

038Dh- 038Ch

Timer A2

Timer A4

Timer A4

038Fh- 038Eh

Timer A3

Timer A0