M37212M4 Datasheet, PDF (47/119 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER

MITSUBISHI MICROCOMPUTERS
M37212M4/M8–XXXSP, M37212M6–XXXSP/FP
M37212EFSP/FP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
with ON-SCREEN DISPLAY CONTROLLER
Set “2C16” to DA-H register.
Set “2816” to DA-L register.
b7 b6 b5 b4 b3 b2 b1 b0
[DA-H _{0 0 1 0 1 1 0 0 DH}
register]
b7 b6 b5 b4 b3 b2 b1 b0
[DA-L register]
1 0 1 0 0 0 DL
At writing of DA-L
At writing of DA-L
b13
b6 b5
b0
[DA latch] 0 0 1 0 1 1 0 0 1 0 1 0 0 0
These bits decide HIGH level area
of fundamental waveform.
HIGH level area of
fundamental waveform
Minimum
resolution bit
width 0.25 µs
!
High-order 8-bit
value of DA latch
These bits decide smaller interval “tm” in which HIGH leval
area is [HIGH level area of fundamental waveform + τ ].
Fundamental
waveform
0.25 µs!44
14-bit
PWM output ^{2C 2B 2A}
…
03
02
01
00
8-bit
counter
FF FE FD ^… D6 D5 D4 D3 ^… 02 01 00
Fundamental waveform of smaller interval
“tm” which is not specified by low-order 6
bits is not changed.
0.25 µs!44
Waveform of smaller interval “tm” specified by low-order 6 bits
0.25 µs!45
14-bit
PWM output
2C
2B
2A
…
03
02
01 00
0.25 µs
8-bit
counter
FF FE FD ^… D6 D5 D4 D3 ^… 02 01 00
τ = 0.25 µs
14-bit PWM output
t0 t1 t2 t3 t4 t5
t59 t60 t61 t62 t63
Low-order 6-bit output of
DA latch
Repeat period
T = 4096 µs @
Fig. 8.7.3 14-bit PWM Timing (f(XIN) = 8 MHz)
Rev. 1.0
47