M38203M4 Datasheet, PDF (40/344 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3820 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
Timer Y
Timer Y is a 16-bit timer that can be selected in one of four modes.
Timer mode
The timer counts f(XIN)/16 (or f(XCIN)/16 in low-speed mode).
Period measurement mode
CNTR1 interrupt request is generated at rising/falling edge of
CNTR1 pin input signal. Simultaneously, the value in timer Y latch
is reloaded in timer Y and timer Y continues counting down/Except
for the above-mentioned, the operation in period measurement
mode is the same as in timer mode.
The timer value just before the reloading at rising/falling of CNTR1
pin input signal is retained until the timer Y is read once after the
reload.
The rising/falling timing of CNTR1 pin input signal is found by
CNTR1 interrupt. When using a timer in this mode, set the corre-
sponding port P55 direction register to input mode.
Event counter mode
The timer counts signals input through the CNTR1 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 corre-
sponding port P55 direction register to input mode.
Pulse width HL continuously measurement mode
CNTR1 interrupt request is generated at both rising and falling
edges of CNTR1 pin input signal. Except for this, the operation in
pulse width HL continuously measurement mode is the same as in
period measurement mode. When using a timer in this mode, set
the corresponding port P55 direction register to input mode.
Note on CNTR1 Interrupt Active Edge Selec-
tion
CNTR1 interrupt active edge depends on the CNTR1 active edge
switch bit. However, in pulse width HL continuously measurement
mode, CNTR1 interrupt request is generated at both rising and
falling edges of CNTR1 pin input signal regardless of the setting of
CNTR1 active edge switch bit.
7
0
Timer Y mode register
(TYM : address 002816)
Not used (return "0" when read)
Timer Y operating mode bits
b5 b4
0 0 : Timer mode
0 1 : Period measurement mode
1 0 : Event counter mode
1 1 : Pulse width HL continuously
measurement mode
CNTR1 active edge switch bit
• CNTR1 interrupt
0 : Falling edge active
1 : Rising edge active
• Period measurement mode
0 : Measure falling edge to falling edge
1 : Measure rising edge to rising edge
• Event counter mode
0 : Rising edge active
1 : Falling edge active
Timer Y stop control bit
0 : Count start
1 : Count stop
Fig. 20 Structure of timer Y mode register
1-24
3820 GROUP USER’S MANUAL