M38047F9HKP datasheet(157/387 Pages) RENESAS

157 / 387 page

2-33

APPLICATION

2.3 Timer

Rev.1.00 Jan 14, 2005

REJ09B0212-0100Z

3804 Group (Spec.H)

(2) Timer application example 1: Clock function (measurement of 250 ms)

Outline: The input clock is divided by the timer so that the clock can count up at 250 ms intervals.

Specifications: •The clock f(XIN) = 4.19 MHz (222 Hz) is divided by the timer.

•The clock is counted up in the process routine of the timer X interrupt which occurs

at 250 ms intervals.

Figure 2.3.15 shows the timers connection and setting of division ratios; Figure 2.3.16 shows the

relevant registers setting; Figure 2.3.17 shows the control procedure.

Fig. 2.3.15 Timers connection and setting of division ratios

Fig. 2.3.16 Relevant registers setting

f(XIN) = 4.19 MHz

250 ms

1/161/2561/256

1/4

1 second

Dividing by 4 with software

Timer X count source

selection bit

Prescaler X

Timer X

Timer X interrupt

request bit

0 or 1

0 : No interrupt request issued

1 : Interrupt request issued

ICON1

Timer X interrupt: Enabled

IREQ1

PREX

256 – 1

T12XCSS

Timer X count source : f(XIN)/16

Timer 12, X count source selection register (address 000E16)

Timer XY mode register (address 002316)

Timer X operating mode: Timer mode

Timer X count: Stop

Clear to “0” when starting count.

Prescaler X (address 002416)

Timer X (address 002516)

Set “division ratio – 1”

Interrupt control register 1 (address 003E16)

Interrupt request register 1 (address 003C16)

Timer X interrupt request

(becomes “1” at 250 ms intervals)

01 1

M38047F9HKP Datasheet(PDF) 157 Page - Renesas Technology Corp

M38047F9HKP Datasheet(HTML) 157 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 Descarga

Enlace URL