Abov MC95FG208 Series, Руководство пользователя

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87
MC95FG308 / MC95FG208
ABOV Semiconductor Co., Ltd.
Figure 11.16 Example of PWM at 4MHz
Figure 11.17 Example of Changing the Period in Absolute Duty Cycle at 4Mhz
Update period & duty register value at once
The period and duty of PWM comes to move from temporary registers to PPR (PWM Period Register) and PDR
(PWM Duty Register) when always period match occurs. If you want that the period and duty is immediately changed,
the UPDT bit in the T1PCR register must set to ‘1’. It should be noted that it needs the 3 cycle of timer clock for data
transfer in the internal clock synchronization circuit. So the update data is written before 3 cycle of timer clock to get
the right output waveform.
T1
00 01 02 03 04
P10/PWM
POLA = 1
T1CR[1:0] = 10
H
(2us)
T1PHR = 00
H
T1PPR = 0E
H
T1ADR = 05
H
09 08 07 06 05 0D 0C 0B 0A 02 01 00 0E 06 05 04 03 0A 09 08 07 03 02 01 00 05 04
Source Clock
(f
x
)
06
Duty Cycle
(1+05
H
)X2us = 12us
Duty Cycle
(1+05
H
)X2us = 12us
Duty Cycle
(1+05
H
)X2us = 12us
Period Cycle
(1+0E
H
)X2us = 32us  31.25kHz
Period Cycle
(1+0A
H
)X2us = 22us  45.5kHz
Write 0A
H
to T1PPR
Source Clock
(f
x
)
Duty Cycle(1+80
H
)X250ns = 32.25us
T1
00 01 02 03 04
7F 80 81 82 3FF 00 01 02
P10/PWM
POLA = 1
P10/PWM
POLA = 0
Period Cycle(1+3FF
H
)X250ns = 256us  3.9kHz
T1PPR(8-bit)
T1ADR(8-bit)
PPR9 PPR8
ADR9 ADR8
1 1 FF
H
0 0 80
H
T1CR[1:0] = 00
H
(f
XIN
)
T1PHR = 03
H
T1PPR = FF
H
T1ADR = 80
H