
16
7510 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
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, if the selected system
clock
φ is f(XCIN)/2).
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.
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.
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.
Note on CNTR 1 Interrupt Active Edge
Selection
CNTR1 interrupt active edge depends on the CNTR1 active edge
selection bit. However, in pulse width HL continuously measure-
ment mode, CNTR1 interrupt request is generated at both rising
and falling edges of CNTR1 pin input signal regardless of the set-
ting of CNTR1 active edge selection bit.
Fig. 11 Structure of timer Y mode register
Not used (return “0” when read)
Timer Y operation 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 selection bit
0 : Count at rising edge in event counter mode
Measure the falling edge to falling edge
period in period measurement mode
Falling edge active for CNTR1 interrupt
1 : Count at falling edge in event counter mode
Measure the rising edge to rising edge
period in period measurement mode
Rising edge active for CNTR1 interrupt
Timer Y stop control bit
0 : Count start
1 : Count stop
b7
Timer Y mode register
(TYM : address 002816)
b0