7721 datasheet(170/577 Pages) RENESAS

170 / 577 page

7721 Group User’s Manual

TIMER B

9–3

9.2 Block description

9.2.1 Counter and reload register (timer Bi register)

Each of timer Bi counter and reload register consists of 16 bits and has the following functions.

(1)

Functions in timer mode and event counter mode

Countdown in the counter is performed each time the count source is input. The reload register is

used to store the initial value of the counter. When a counter underflow occurs, the reload register’s

contents are reloaded into the counter.

A value is set to the counter and reload register by writing the value to the timer Bi register. Table

9.2.1 lists the memory assignment of the timer Bi register.

The value written into the timer Bi register when the counting is not in progress is set to the counter

and reload register. The value written into the timer Bi register when the counting is in progress is

set only to the reload register. In this case, the reload register’s updated contents are transferred to

the counter when the next underflow occurs. The counter value is read out by reading out the timer

Bi register.

Note: When reading from or writing to the timer Bi register, perform it in a unit of 16 bits. For more

information about the value obtained by reading the timer Bi register, refer to “[Precautions

for timer mode]” and “[Precautions for event counter mode].”

(2)

Functions in pulse period/pulse width measurement mode

Countup in the counter is performed each time the count source is input. The reload register is used

to retain the pulse period or pulse width measurement result. When a valid edge is input to the TBjIN

pin, the counter value is transferred to the reload register. In this mode, the value obtained by

reading the timer Bj register is the reload register’s contents, so that the measurement result is

obtained.

Note: When reading from the timer Bj register, perform it in a unit of 16 bits.

Timer Bi register

Timer B0 register

Timer B1 register

Timer B2 register

Low-order byte

Address 5016

Address 5216

Address 5416

High-order byte

Address 5116

Address 5316

Address 5516

Note : At reset, the contents of the timer Bi

Table 9.2.1 Memory assignment of timer Bi registers

7721 Datasheet(PDF) 170 Page - Renesas Technology Corp

7721 Datasheet(HTML) 170 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