M37221M4H_15 Datasheet, PDF (49/114 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER

M37221M4H/M6H/M8H/MAH–XXXSP/FP M37221EASP/FP
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.
Minimum
HIGH level area of
fundamental waveform
=
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.1.00 Oct 01, 2002 page 47 of 110
REJ03B0134-0100Z