R8CSLASH20 datasheet(267/501 Pages) RENESAS

267 / 501 page

R8C/20 Group, R8C/21 Group

14. Timers

Rev.2.00 Aug 27, 2008

Page 251 of 458

REJ09B0250-0200

14.3.12 Notes on Timer RD

14.3.12.1 TRDSTR Register

• Set the TRDSTR register using the MOV instruction.

• When the CSELi (i = 0 or 1) is set to 0 (the count stops at compare match of registers TRDi and

TRDGRAi), the count does not stop and the TSTARTi bit remains unchanged even if 0 (count stops) is

written to the TSTARTi bit.

Therefore, set the TSTARTi bit to 0 to change other bits without changing the TSTARTi bit when the

CSELi bit is set to 0.

To stop counting by a program, set the TSTARTi bit to 0 after setting the CSELi bit to 1. Although the

CSELi bit is set to 1 and the TSTARTi bit is set to 0 at the same time (with 1 instruction), the count cannot

be stopped.

• Table 14.36 lists the TRDIOji (j = A, B, C, or D) Pin Output Level when Count Stops to use the TRDIOji

pin with the timer RD output.

14.3.12.2 TRDi Register (i = 0 or 1)

• When writing the value to the TRDi register by a program while the TSTARTi bit in the TRDSTR register

is set to 1 (count starts), avoid to overlap with the timing to set the TRDi register to 0000h, and then write.

When the timing to set the TRDi register to 0000h overlaps with the timing to write the value to the TRDi

These precautions are applicable when selecting the following by the CCLR2 to CCLR0 bits in the

TRDCRi register.

- 001b (clear by the TRDi register at the compare match with the TRDGRAi register)

- 010b (clear by the TRDi register at the compare match with the TRDGRBi register.)

- 011b (synchronous clear)

- 101b (clear by the TRDi register at the compare match with the TRDGRCi register.)

- 110b (clear by the TRDi register at the compare match with the TRDGRDi register.)

• When writing the value to the TRDi register and continuously reading the same register, the value before

writing may be read. In this case, execute the JMP.B instruction between the writing and reading.

Program Example

MOV.W

#XXXXh, TRD0

;Writing

JMP.B

;JMP.B

L1:

MOV.W

TRD0,DATA

;Reading

14.3.12.3 TRDSRi Register (i = 0 or 1)

When writing the value to the TRDSRi register and continuously reading the same register, the value before

writing may be read. In this case, execute the JMP.B instruction between the writing and reading.

Program Example

MOV.B

#XXh, TRDSR0

;Writing

JMP.B

;JMP.B

L1:

MOV.B

TRDSR0,DATA

;Reading

Table 14.36

TRDIOji (j = A, B, C, or D) Pin Output Level when Count Stops

Count Stop

TRDIOji Pin Output when Count Stops

When the CSELi bit is set to 1, set the TSTARTi bit to 0 and the count

stops.

Hold the output level immediately before the

count stops.

When the CSELi bit is set to 0, the count stops at compare match of

registers TRDi and TRDGRAi.

Hold the output level after output changes by

compare match.

R8C/20 Datasheet(PDF) 267 Page - Renesas Technology Corp

R8C/20 Datasheet(HTML) 267 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