M38022M4 Datasheet, PDF (75/207 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.2 Timer
Timer XY mode register (Address : 2316)
b7
b0
TM
11 1 0
Timer Y operating mode bit : Event counter mode
Prescaler 12 (Address : 2016)
b7
b0
PRE12
63
CNTR1 active edge switch bit : Count at falling edge
Timer Y count stop bit : Count stop
Set to “0” at starting to count.
Timer 1 (Address : 2116)
b7
b0
T1
7
Set “division ratio – 1”
PREY
Prescaler Y (Address : 2616)
b7
b0
0
Timer Y (Address : 2716)
b7
b0
TY
255
Set “255” to this register immediately before
counting pulse.
(After a certain time, this value is decreased by
the number of input pulses)
ICON1
Interrupt control register 1 (Address : 3E16)
b7
b0
10
Timer Y interrupt enable bit : Interrupt disabled
Timer 1 interrupt enable bit : Interrupt enabled
IREQ1
Interrupt request register 1 (Address : 3C16)
b7
b0
0
Judgment of Timer Y interrupt request bit
(When this bit is set to “1” at reading out
the count value of the Timer Y (address : 2716),
256 pulses or more are input (at setting 255 to
the Timer Y).)
Fig. 2.2.18 Setting of related registers [Measurement of frequency]
2-18
3802 GROUP USER’S MANUAL