M38B71M1 datasheet(27/110 Pages) RENESAS | SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

27 / 110 page

38B7 Group

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS

16-Bit Timer

Timer X is a 16-bit timer that can be selected in one of four modes by

the Timer X mode registers 1, 2 and can be controlled for the timer X

write and the real time port by setting the timer X mode registers.

Read and write operation on 16-bit timer must be performed for both

high- and low-order bytes. When reading a 16-bit timer, read from

the high-order byte first. When writing to 16-bit timer, write to the low-

order byte first. The 16-bit timer cannot perform the correct operation

when reading during write operation, or when writing during read

operation.

qTimer X

Timer X is a down-counter. When the timer reaches “000016”, an

underflow occurs with the next count pulse. Then the contents of the

timer latch is reloaded into the timer and the timer continues down-

counting. When a timer underflows, the interrupt request bit corre-

sponding to that timer is set to “1”.

(1) Timer mode

A count source can be selected by setting the Timer X count source

selection bits (bits 1 and 2) of the Timer X mode register 1.

(2) Pulse output mode

Each time the timer underflows, a signal output from the CNTR2 pin

is inverted. Except for this, the operation in pulse output mode is the

same as in timer mode. When using a timer in this mode, set the port

shared with the CNTR2 pin to output.

(3) Event counter mode

The timer counts signals input through the CNTR2 pin. Except for

this, the operation in event counter mode is the same as in timer

mode. When using a timer in this mode, set the port shared with the

CNTR2 pin to input.

(4) Pulse width measurement mode

A count source can be selected by setting the Timer X count source

selection bits (bits 1 and 2) of the Timer X mode register 1. When

CNTR2 active edge switch bit is “0”, the timer counts while the input

signal of the CNTR2 pin is at “H”. When it is “1”, the timer counts

while the input signal of the CNTR2 pin is at “L”. When using a timer

in this mode, set the port shared with the CNTR2 pin to input.

s Note

•Timer X Write Control

If the timer X write control bit is “0”, when the value is written in the

address of timer X, the value is loaded in the timer X and the latch at

the same time.

If the timer X write control bit is “1”, when the value is written in the

address of timer X, the value is loaded only in the latch. The value in

the latch is loaded in timer X after timer X underflows.

When the value is written in latch only, unexpected value may be set

in the high-order counter if the writing in high-order latch and the

underflow of timer X are performed at the same timing.

•Real Time Port Control

While the real time port function is valid, data for the real time port

are output from ports P94 and P95 each time the timer X underflows.

(However, if the real time port control bit is changed from “0” to “1”,

data are output independent of the timer X.) When the data for the

real time port is changed while the real time port function is valid, the

changed data are output at the next underflow of timer X.

Before using this function, set the corresponding port direction regis-

ters to output mode.

M38B71M1 Datasheet(PDF) 27 Page - Renesas Technology Corp

M38B71M1 Datasheet(HTML) 27 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

Related Electronics Part Number

Link URL