7477 datasheet(81/354 Pages) RENESAS

81 / 354 page

7470/7471/7477/7478 GROUP USER’S MANUAL

1-64

HARDWARE

1.12 Timers

1.12.1 Operation description

In a write operation, the timer latch is specified at the same time when the timer is specified. If the timer

is set to n16, the timer latch is also set to n16 (n: 0016 to FF16). After the timer starts to count,

1 the timer value is counted down as n16 → (n-1)16 → (n-2)16 → ... → 116 → 016 → FF16 at each rise

of the count source.

2 At the next rise of the count source after “FF16,”

q (n-1)16 resulting from decrementing 1 from the timer latch value is set (reloaded) in the timer and

then the timer continues to count.

q When an overflow occurs, the interrupt request bit is set to “1.”

Note: When the interrupt is accepted, the interrupt request bit changes from “1” to “0.” It can be

clearned to “0” but cannot be set to “1” by software.

Figure 1.12.2 shows a timer count timing.

Fig. 1.12.2 Timer count timing

n16

(n–1)16

!!16

n16

016

(n–2)16 (n–3)16

(n–1)16

(n–1)16 (n–2)16 (n–3)16

Count operation stop

Count start

Count stop bit

Timer count source

Value of timer

Timer interrupt

request bit

Reload

Writing to timer

Read value of timer

(!!+1)16

FF16

116

FF16

(n–1)16

016

116

7477 Datasheet(PDF) 81 Page - Renesas Technology Corp

7477 Datasheet(HTML) 81 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