m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 33

• Manufacturer Part Number: m3819
• Description: Mitsubishi 8-bit Single-chip Microcomputer 740 Family / 38000 Series
• Manufacturer: Renesas Electronics Corporation.

TIMERS
The 3819 group has 6 built-in timers: timer 1, timer 2, timer 3,
timer 4, timer 5, and timer 6.
Each timer has the 8-bit timer latch. The timers count down.
Once a timer reaches 00
each timer latch is loaded into the corresponding timer, and sets
the corresponding interrupt request bit to “1”.
The count can be stopped by setting the stop bit of each timer to
“1”. The internal clock
or low-speed mode with the CPU mode register. At the same time,
timer internal count source is switched to either f(X
Timer 1 and Timer 2
The count sources of timer 1 and timer 2 can be selected by set-
ting the timer 12 mode register. A rectangular waveform of timer 1
underflow signal divided by 2 is output from the P4
The waveform polarity changes each time timer 1 overflows. The
active edge of the external clock CNTR
bit 6 of the interrupt edge selection register.
At reset or when executing the STP instruction, all bits of the timer
12 mode register are cleared to “0”, timer 1 is set to “FF
timer 2 is set to “01
Timer 3 and Timer 4
The count sources of timer 3 and timer 4 can be selected by set-
ting the timer 34 mode register. A rectangular waveform of timer 3
underflow signal divided by 2 is output from the P4
The waveform polarity changes each time timer 3 overflows.
The active edge of the external clock CNTR
the bit 7 of the interrupt edge selection register.
Timer 5 and Timer 6
The count sources of timer 5 and timer 6 can be selected by set-
ting the timer 56 mode register.
A rectangular waveform of timer 6 underflow signal divided by 2 is
output from the P6
each time timer 6 overflows.
Timer 6 PWM Mode
Timer 6 can output a rectangular waveform with duty cycle n/(n +
m) from the P6
(refer to fig. 12). The n is the value set in timer 6 latch (address
0025
0027
put is “H”(n=0 is prior than m=0). In the PWM mode, interrupts
occur at the rising edge of the PWM output.
16
16
). If n is “0”, the PWM output is “L”, if m is “0”, the PWM out-
) and m is the value in the timer 6 PWM register (address
1
/PWM pin by setting the timer 56 mode register
16
1
/PWM pin. The waveform polarity changes
”.
can be set to either the high-speed mode
16
, at the next count pulse the contents of
0
can be switched with the
1
can be switched with
IN
) or f(X
6
7
/T1
/T3
OUT
OUT
16
CIN
”, and
pin.
pin.
).
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
3819 Group
19