
MITSUBISHI MICROCOMPUTERS
M37207MF-XXXSP/FP, M37207M8-XXXSP
M37207EFSP/FP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
and ON-SCREEN DISPLAY CONTROLLER
42
Fig. 37. 14-bit PWM (DA) Output Example (at f(X
IN
)
= 8 MHz)
250 ns
b7
0
b0
0
b6 b5 b4
0
1
b3 b2
1
b1
0
0
1
b13
0
b6
0
0
1
0
1
1
0
b0
0
b5
1
0
1
0
0
Set “2C
16
” to DA-H register.
[DA-H
register]
D
H
At writing of DA-L
b0
0
b6
b5 b4
1
b3 b2
1
b1
0
0
0
Set “28
16
” to DA-L register.
[DA-L register]
D
L
At writing of DA-L
Undefined
These bits decide “H” level area of
fundamental waveform.
Minimum
resolution bit
width 250 ns
These bits decide smaller interval “tm” in which “H” leval
area is [“H” level area of fundamental waveform +
τ
].
=
High-order 8-bit
value of DA latch
“H” level area of
fundamental waveform
FF
00
D3
FE FD…
…
…
…
D6
D4
02 01
D5
14-bit
PWM output
8-bit
counter
250 ns
44
FF
00
D3
FE FD
D6
D4
02 01
D5
14-bit
PWM output
8-bit
counter
250 ns
44
Fundamental
waveform
Waveform of smaller interval “tm” specified by low-order 6 bits
Fundamental waveform of smaller interval
“tm” which is not specified by low-order 6
bits is not changed.
14-bit PWM output
Low-order 6-bit
output of DA latch
250 ns
44
τ
= 250 ns
T
=
4096 μ
s
Repeat period
t
0
t
1
t
2
t
3
t
4
t
5
t
59
t
60
t
61
t
62
t
63
[DA latch]
b7
2C 2B 2A … 03 02 01 00
2C 2B 2A … 03 02 01 00
2D
2D
Latch transfer complete bit
Transfer complete
Transfer is not completed
(Automatically set at writing)
0
1