R8CSLASH15 datasheet(253/277 Pages) RENESAS

253 / 277 page

R8C/14 Group, R8C/15 Group

20. Precautions

Rev.2.10

Jan 19, 2006

Page 241 of 253

REJ09B0164-0210

20.4.3

Timer Z

• Do not rewrite the TZMOD0 to TZMOD1 bits and the TZS bit simultaneously.

• In programmable one-shot generation mode and programmable wait one-shot generation mode,

when setting the TZS bit in the TZMR register to “0” (stops counting) or setting the TZOS bit in

the TZOC register to “0” (stops one-shot), the timer reloads the value of reload register and stops.

Therefore, read the timer count value in programmable one-shot generation mode and

programmable wait one-shot generation mode before the timer stops.

• The TZS bit in the TZMR register has a function to instruct Timer Z to start or stop counting, and

a function to indicate the count starts or stops.

“0” (count stops) can be read until the following count source is applied after “1” (count starts) is

written to the TZS bit while the count is being stopped. If the following count source is applied, “1”

can be read from the TZS bit. Do not access registers associated with Timer Z (TZMR, PREZ,

TZSC, TZPR, TZOC, PUM, TCSC, TZIC registers) except for the TZS bit until “1” can be read

from the TZS bit. The count starts at the following count source after the TZS bit is set to “1”.

Also, when writing “0” (count stops) to the TZS bit during the count, Timer Z stops counting at the

following count source.

“1” (count starts) can be read by reading the TZS bit until the count stops after writing “0” to the

TZS bit. Do not access registers associated with Timer Z other than the TZS bit until “0” can be

read by the TZS bit after writing “0” to the TZS bit.

20.4.4

Timer C

Access the TC, TM0 and TM1 registers in 16-bit units.

The TC register can be read in 16-bit units. This prevents the timer value from being updated

between the low-order byte and high-order byte are being read.

Example (when Timer C is read):

MOV.W

0090H,R0

; Read out timer C

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