Renesas 16-bit single-chip microcomputer Manual De Usuario

Rev.1.02    Jul 01, 2005    page 94 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

f1, f2, f8, f32, fC32

Count Operation

• Down-count

• When the timer underflows, it reloads the reload register contents and continues counting

Divide Ratio

1/(n+1)

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 underflow

TAiIN Pin Function

I/O port or gate input

TAiOUT Pin Function

I/O port or pulse output

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 the TAi register is written to both reload register and counter

• When counting (after 1st count source input)

Value written to the TAi register is written to only reload register

(Transferred to counter when reloaded next)

Select Function

• Gate function

Counting can be started and stopped by an input signal to TAiIN pin

• Pulse output function

Whenever the timer underflows, the output polarity of TAiOUT pin is inverted.

When TAiS bit is set to “0 ” (stop counting), the pin outputs a low.

In timer mode, the timer counts a count source generated internally. Table 12.1 lists specifications in

timer mode. Figure 12.7 shows TAiMR register in timer mode.

NOTE:

1. The port direction bit for the TAiIN pin is set to "0" (input mode).

Timer Ai Mode Register (i = 0 to 4)

Symbol

TA0MR to TA4MR

Bit Name

Function

Bit Symbol

RW

b7

b6

b5

b4

b3

b2

b1

b0

Operation Mode
Select Bit

 

0 0 : Timer mode

b1 b0 

TMOD1

TMOD0 

MR0

Pulse Output Function 
Select Bit

0 : Pulse is not output
     (TAiOUT pin is a normal port pin)
1 : Pulse is output 

      (TAiOUT pin is a pulse output pin)

Gate Function Select Bit

0 0 :

      

Gate function not available

0 1 :      (TAiIN pin functions as I/O port)
1 0 : Counts while input on the TAiIN pin
        is low 

(1)

1 1 : Counts while input on the TAiIN pin
        is high 

(1)

b4 b3

MR2

MR1

MR3

Set to "0" in timer mode

0 0 : f1 or f2
0 1 : f8
1 0 : f32
1 1 : fC32

b7 b6 

TCK1

TCK0

Count Source Select Bit

0 0

0

RW

RW

RW

RW

RW

RW

RW

RW

}

Address

0396h to 039Ah

After Reset

00h

 i = 0 to 4