R8CSLASH20 datasheet(160/501 Pages) RENESAS

160 / 501 page

R8C/20 Group, R8C/21 Group

14. Timers

Rev.2.00 Aug 27, 2008

Page 144 of 458

REJ09B0250-0200

14.2.2

Programmable Waveform Generation Mode

Programmable waveform generation mode is mode to invert the signal output from the TRBO pin each time the

counter underflows, while the values in the TRBPR and TRBSC registers are counted alternately (see Table

14.8 Programmable Waveform Generation Mode Specifications). A counting starts by counting the setting

value in the TRBPR register. The TRBOCR register is unused in this mode.

Figure 14.19 shows the TRBIOC Register in Programmable Waveform Generation Mode. Figure 14.20 shows

the Operation Example of Timer RB in Programmable Waveform Generation Mode.

NOTES:

1. Even when counting the secondary period, read out the TRBPR register.

2. The set values are reflected to the waveform output beginning with the following primary period after

writing to the TRBPR register.

3. The value written to the TOCNT bit is enabled by the following.

• When count starts.

• When the timer RB interrupt request is generated.

The contents after the TOCNT bit is changed are reflected from the output of the following

primary period.

Table 14.8

Programmable Waveform Generation Mode Specifications

Item

Specification

Count Sources

f1, f2, f8, timer RA underflow

Count Operations

• Decrement

• When the timer underflows, it reloads the contents of the primary reload and

secondary reload registers alternately before the count continues.

Width and Period of

Output Waveform

Primary period: (n+1)(m+1)/fi

Secondary period: (n+1)(p+1)/fi

Period: (n+1){(m+1)+(p+1)}/fi

fi: Count source frequency

n: Setting value in TRBPRE register

m: Setting value in TRBPR register

p: Setting value in TRBSC register

Count Start Condition Write 1 (count start) to the TSTART bit in the TRBCR register

Count Stop

Conditions

• Write 0 (count stop) to the TSTART bit in the TRBCR register

• Write 1 (count forcibly stop) to the TSTOP bit in the TRBCR register

Interrupt Request

Generation Timing

In half of count source, after timer RB underflows during secondary period (at the

same time as the TRBO output change) [timer RB interrupt]

TRBO Pin Function

Programmable output port or pulse output

INT0 Pin Function

Programmable I/O port or INT0 interrupt input

Read from Timer

The count value can be read out by reading the TRBPR and TRBPRE registers(1)

Write to Timer

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

stopped, 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.(2)

Select Functions

• Output level select function

The TOPL bit can select the output level during primary and secondary periods.

• TRBO pin output switch function

Timer RB pulse output or P3_1 latch output is selected by the TOCNT bit in the

TRBIOC register.(3)

R8C/20 Datasheet(PDF) 160 Page - Renesas Technology Corp

R8C/20 Datasheet(HTML) 160 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