R8C datasheet(86/199 Pages) RENESAS

86 / 199 page

R8C/10 Group

Rev.1.20 Jan 27, 2006

page 76 of 180

REJ09B0019-0120

12.3.1 Timer Mode

In this mode, the timer counts an internally generated count source or Timer Y underflow (see “Table

12.9 Timer Mode Specifications”). The Timer Z secondary is unused in timer mode. Figure 12.22

shows the TYZMR register and PUM register in timer mode.

Item

Specification

Count source

f1, f2, f8, Timer Y underflow

Count operation

• Down-count

• When the timer underflows, it reloads the reload register contents before continuing

counting (When the Timer Z underflows, the contents of the Timer Z primary reload

Divide ratio

1/(n+1)(m+1)

n: set value in PREZ register, m: set value in TZPR register

Count start condition

Write “1” (count start) to TZS bit in TYZMR register

Count stop condition

Write “0” (count stop) to TZS bit in TYZMR register

Interrupt request

• When Timer Z underflows [Timer Z interrupt]

generation timing

TZOUT pin function

Programmable I/O port

INT0 pin function

_______

Programmable I/O port, or INT0 interrupt input

Read from timer

Count value can be read out by reading TZPR register.

Same applies to PREZ register.

Write to timer(1)

Value written to TZPR register is written to both reload register and counter or written to

reload register only. Selected by program.

Same applies to PREZ register.

NOTES:

1. The IR bit in the TZIC register is set to "1" (interrupt requested) if you write to the TZPR or PREZ register while both

of the following conditions are met.

• TZWC bit in TYZMR register is set to "0" (write to reload register and counter simultaneously)

• TZS bit in TYZMR register is set to "1" (count start)

To write to the TZPR or PREZ register in the above state, disable interrupts before the writing.

Table 12.9 Timer Mode Specifications

12.3 Timer (Timer Z)

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