R29 datasheet(185/473 Pages) RENESAS

185 / 473 page

R8C/28 Group, R8C/29 Group

14. Timers

Rev.2.10

Sep 26, 2008

Page 166 of 441

REJ09B0279-0210

14.2.4

Programmable Wait One-Shot Generation Mode

In programmable wait one-shot generation mode, a one-shot pulse is output from the TRBO pin by a program

or an external trigger input (input to the INT0 pin) (refer to Table 14.10 Specifications of Programmable Wait

One-Shot Generation Mode). When a trigger is generated from that point, the timer outputs a pulse only once

for a given length of time equal to the setting value in the TRBSC register after waiting for a given length of

time equal to the setting value in the TRBPR register.

Figure 14.22 shows the TRBIOC Register in Programmable Wait One-Shot Generation Mode. Figure 14.23

shows an Operating Example of Programmable Wait One-Shot Generation Mode.

NOTES:

1. The set value is reflected at the following one-shot pulse after writing to registers TRBSC and TRBPR.

2. Do not set both the TRBPRE and TRBPR registers to 00h.

3. Set the TRBOSEL bit in the PINSR2 register to 1 (enabled) before using timer RB.

Refer to 7. Programmable I/O Ports for details.

Table 14.10

Specifications of Programmable Wait One-Shot Generation Mode

Item

Specification

Count sources

f1, f2, f8, timer RA underflow

Count operations

• Decrement the timer RB primary setting value.

• When a count of the timer RB primary underflows, the timer reloads the contents of

timer RB secondary before the count continues.

• When a count of the timer RB secondary underflows, the timer reloads the contents of

timer RB primary before the count completes and the TOSSTF bit is set to 0 (one-shot

stops).

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

stops.

Wait time

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

fi: Count source frequency

n: Value set in the TRBPRE register, m Value set in the TRBPR register(2)

One-shot pulse

output time

(n+1)(p+1)/fi

fi: Count source frequency

n: Value set in the TRBPRE register, p: Value set in the TRBSC register

Count start

conditions

• The TSTART bit in the TRBCR register is set to 1 (count starts) and the next trigger is

generated.

• Set the TOSST bit in the TRBOCR register to 1 (one-shot starts).

• Input trigger to the INT0 pin

Count stop

conditions

• When reloading completes after timer RB underflows during secondary period.

• When the TOSSP bit in the TRBOCR register is set to 1 (one-shot stops).

• When the TSTART bit in the TRBCR register is set to 0 (starts counting).

• When the TSTOP bit in the TRBCR register is set to 1 (forcibly stops counting).

Interrupt request

generation timing

In half a cycle of the count source after timer RB underflows during secondary period

(complete at the same time as waveform output from the TRBO pin) [timer RB interrupt]

TRBO pin function

Pulse output(3)

INT0 pin functions

• When the INOSTG bit in the TRBIOC register is set to 0 (INT0 one-shot trigger

disabled): programmable I/O port or INT0 interrupt input

• When the INOSTG bit in the TRBIOC register is set to 1 (INT0 one-shot trigger

enabled): external trigger (INT0 interrupt input)

Read from timer

The count value can be read out by reading registers TRBPR and TRBPRE.

Write to timer

• When registers TRBPRE, TRBSC, and TRBPR are written while the count stops,

values are written to both the reload register and counter.

• When registers TRBPRE, TRBSC, and TRBPR are written to during count operation,

values are written to the reload registers only.(1)

Select functions

• Output level select function

The TOPL bit in the TRBIOC register selects the output level of the one-shot pulse

waveform.

• One-shot trigger select function

Refer to 14.2.3.1 One-Shot Trigger Selection.

R29 Datasheet(PDF) 185 Page - Renesas Technology Corp

R29 Datasheet(HTML) 185 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL