R8CSLASH20 datasheet(268/501 Pages) RENESAS

268 / 501 page

R8C/20 Group, R8C/21 Group

14. Timers

Rev.2.00 Aug 27, 2008

Page 252 of 458

REJ09B0250-0200

14.3.12.4 Count Source Switch

• When switching the count source, switch it after the count stops.

Change procedure

(1) Set the TSTARTi (i = 0 or 1) bit in the TRDSTR register to 0 (count stops).

(2) Change the TCK2 to TCK0 bits in the TRDCRi register.

• When changing the count source from fOCO40M to the other and stopping fOCO40M, wait 2 cycles or

more of f1 after setting the clock switch, and then stop fOCO40M.

Change procedure

(1) Set the TSTARTi (i = 0 or 1) bit in the TRDSTR register to 0 (count stops).

(2) Change the TCK2 to TCK0 bits in the TRDCRi register.

(3) Wait 2 cycles or more of f1.

(4) Set the FRA00 bit in the FRA0 register to 0 (high-speed on-chip oscillator stops).

14.3.12.5 Input Capture Function

• Set the pulse width of input capture signal to 3 cycles or more of the Timer RD operation clock. (Refer to

Table 14.11 Timer RD Operation Clocks.)

• The value in the TRDi register is transferred to the TRDGRji register after 2 to 3 cycles of the Timer RD

operation clock since the input capture signal is applied to the TRDIOji pin (i = 0 or 1, j = either A, B, C or

D) (no digital filter).

14.3.12.6 Reset Synchronous PWM Mode

• When reset synchronous PWM mode is used for motor control, use it with OLS0 = OLS1.

• Set to reset synchronous PWM mode in the following procedure:

Change procedure

(1) Set the TSTART0 bit in the TRDSTR register to 0 (count stops).

(2) Set the CMD1 to CMD0 bits in the TRDFCR register to 00b (timer mode, PWM mode, and PWM3

mode).

(3) Set the CMD1 to CMD0 bits to 01b (reset synchronous PWM mode).

(4) Set the registers associated with other Timer RD again.

14.3.12.7 Complementary PWM Mode

• When complementary PWM mode is used for motor control, use it with OLS0 = OLS1.

• Change the CMD1 to CMD0 bits in the TRDFCR register in the following procedure.

Change procedure: When setting to complementary PWM mode (including re-set), or changing

the transfer timing from the buffer register to the general register in complementary PWM

mode.

(1) Set both the TSTART0 and TSTART1 bits in the TRDSTR register to 0 (count stops).

(2) Set the CMD1 to CMD0 bits in the TRDFCR register to 00b (timer mode, PWM mode, and PWM3

mode)

(3) Set the DMD1 to CMD0 bits to 10b or 11b (complementary PWM mode).

(4) Set the registers associated with other Timer RD again.

Change procedure: When stopping complementary PWM mode

(1) Set both the TSTART0 and CSEL1 bits in the TRDSTR register to 0 (count stops).

(2) Set the CMD1 to CMD bits to 00b (other than reset synchronous PWM mode, complementary PWM

mode)

• Do not write to the TRDGRA0, TRDGRB0, TRDGRA1 and TRDGRB1 registers during operation.

When changing the PWM waveform, transfer the value written to the TRDGRD0, TRDGRC1 and

TRDGRD1 registers to the TRDGRB0, TRDGRA1 and TRDGRB1 registers using the buffer operation.

However, to write data to the TRDGRD0, TRDGRC1, or TRDGRD1 register, set bits BFD0, BFC1, and

BFD1 to 0 (general register). After this, bits BFD0, BFC1, and BFD1 may be set to 1 (buffer register).

The PWM period cannot be changed.

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