M37544G Mitsubishi Electric, M37544G Datasheet - Page 21

• Manufacturer Part Number: M37544G
• Description: Single-Chip 8-Bit CMOS Microcomputer
• Manufacturer: Mitsubishi Electric

(3) Event counter mode
Timer A counts signals input from the P0
Except for this, the operation in event counter mode is the same
as in timer mode.
The active edge of CNTR
rising or falling by the CNTR
(4) Pulse width HL continuously measurement mode
In the pulse width HL continuously measurement mode, the pulse
width (“H” and “L” levels) input to the P0
CNTR
edges of CNTR
pulse width HL continuously measurement mode is the same as in
period measurement mode.
The count value when trigger input from the CNTR
cepted is retained until Timer A is read once.
Timer A can stop counting by setting “1” to the timer A count stop
bit in any mode.
Also, when Timer A underflows, the timer A interrupt request bit is
set to “1”.
Note on Timer A is described below;
CNTR
CNTR
switch bit.
When this bit is “0”, the CNTR
the falling edge of the CNTR
the CNTR
the CNTR
However, in the pulse width HL continuously measurement mode,
CNTR
edges of CNTR
CNTR
Note on Timer A
1
1
1
1
1
interrupt active edge selection
active edge switch bit.
interrupt active edge depends on the CNTR
interrupt request is generated at both rising and falling
interrupt request is generated at both rising and falling
1
1
pin input signal.
interrupt request bit is set to “1” at the rising edge of
1
1
pin input signal. Except for this, the operation in
pin input signal regardless of the setting of
1
pin input signal can be selected from
1
1
active edge switch bit .
1
pin input signal. When this bit is “1”,
interrupt request bit is set to “1” at
0
0
/CNTR
/CNTR
1
1
pin is measured.
pin.
1
1
active edge
pin is ac-
Fig. 20 Structure of timer A mode register
Fig. 21 Timer count source set register 2
b7
b7
Note : System operates using a ring oscillator as a count source
by setting the ring oscillator to oscillation enabled by bit 3
of CPUM.
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
b0
b0
MITSUBISHI MICROCOMPUTERS
Disable (return “0” when read)
Timer A operating mode bits
b5 b4
CNTR
Timer A count stop bit
0
0
1
1
0 : Count at rising edge in event counter mode
1 : Count at falling edge in event counter mode
0 : Count start
1 : Count stop
Timer count source set register 2
(TCSS2 : address 002F
Timer A mode register
(TAM : address 001D
Timer 1 count source selection bits
Timer A count source selection bits
Disable (return “0” when read)
Measure the falling edge period in period
Falling edge active for CNTR
Measure the rising edge period in period
measurement mode
Rising edge active for CNTR
measurement mode
0 : Timer mode
1 : Period measurement mode
0 : Event counter mode
1 : Pulse width HL continuously
b1 b0
0
0
1
1
b3 b2
0
0
1
1
1
measurement mode
active edge switch bit
0 : f(X
1 : f(X
0 : Ring oscillator output
1 : Disable
0 : f(X
1 : f(X
0 : Ring oscillator output
1 : Disable
IN
IN
IN
IN
)/16
)/2
)/16
)/2
7544 Group
16
, initial value: 00
16
, initial value: 00
1
1
interrupt
interrupt
16
)
16
)
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