R8C12 datasheet(93/198 Pages) RENESAS

93 / 198 page

R8C/12 Group

Rev.1.20

Jan 27, 2006

page 83 of 181

REJ09B0110-0120

12.3.4 Programmable Wait One-shot Generation Mode

In this mode, upon program or external trigger input (input to the INT0 pin), the microcomputer outputs

the one-shot pulse from the TZOUT pin after waiting for a given length of time (see “Table 12.12

Programmable Wait One-shot Generation Mode Specifications”). When a trigger occurs, from this

point, the timer starts outputting pulses only once for a given length of time equal to the set value in the

TZSC register after waiting for a given length of time equal to the set value in the TZPR register.

Figure 12.26 shows the TYZMR and PUM registers in this mode. Figure 12.27 shows an operation

example in this mode.

Item

Specification

Count source

f1, f2, f8, Timer Y underflow

Count operation

• Downcounts set value in Timer Z primary

• When a counting of TZPR register underflows, the timer reloads the contents of TZSC

• When a counting of TZSC register underflows, the timer reloads the contents of TZPR

• When a count stops, the timer reloads the contents of the reload register before it stops.

Wait time

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

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

One-shot pulse output time (n+1)(p+1)/fi

n : set value in PREZ, p: set value in TZSC register

Count start condition

• Set TZOS bit in TYZOC register to “1” (start one-shot)(1)

_______

• Input active trigger to INT0 pin(2)

Count stop condition

• When reloading is completed after count value at counting TZSC register was set to

"0016"

• When TZS bit in TYZMR register is set to “0” (stop counting)

• When TZOS bit in TYZOC register is set to “0” (stop one-shot)

Interrupt request generation timing In half cycles of count source, after count value at counting TZSC register is set "0016"

(at the same time as the TZout output change) [Timer Z interrupt]

TZOUT pin function

Pulse output

Use timer mode when using this pin as a programmable I/O port.

_______

INT0 pin function

_______

Programmable I/O port, INT0 interrupt input or external trigger input

_______

• When the INOSTG bit in the PUM register is set to “0” (INT0 one-shot trigger disabled)

_______

Programmable I/O port or INT0 interrupt input

_______

• When the INOSTG bit in the PUM register is set to “1” (INT0 one-shot trigger enabled)

_______

external trigger (INT0 interrupt input)

Read from timer

Count value can be read out by reading TZPR register.

Same applies to PREZ register.

Write to timer

Value written to TZPR register and PREZ register are written to reload register only(3).

Same applies to TZSC register.

Select function

• Output level latch select function

Output level for one-shot pulse waveform is selected by TZOPL bit.

_______

• INT0 pin one-shot trigger control function and polarity select function

_______

Trigger input from INT0 pin can be set to active or inactive by INOSTG bit. Also, an

active trigger's polarity can be selected by INOSEG bit.

NOTES:

1. The TZS bit in the TYZMR register must be set to "1" (start counting).

_______

2. The TZS bit must be set to "1" (start counting), the INT0EN bit in the INTEN register to "1" (enabling INT0 input), and

the INOSTG bit in the PUM register to "1" (enabling INT0 one-shot trigger).

_______

Although the trigger input during counting cannot be acknowledged, the INT0 interrupt request is generated.

3. The set values are reflected beginning with the next one-shot pulse after writing to the TZPR register.

12.3 Timer (Timer Z)

Table 12.12 Programmable Wait One-shot Generation Mode Specifications

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