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BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
Timer/Counter Mode
To select this mode, bits PT0M1 and PT0M0 in the PTM0C1 register should be set to 11
respectively. The Timer/Counter Mode operates in an identical way to the Compare Match Output
Mode generating the same interrupt flags. The exception is that in the Timer/Counter Mode the
PTM
0 output pin is not used. Therefore the above description and Timing Diagrams for the Compare
Match Output Mode can be used to understand its function.
PWM Output Mode
To select this mode, bits PT0M1 and PT0M0 in the PTM0C1 register should be set to 10
respectively. The PWM function within the PTM0 is useful for applications which require functions
such as motor control, heating control, illumination control etc. By providing a signal of fixed
frequency but of varying duty cycle on the PTM0 output pin, a square wave AC waveform can be
generated with varying equivalent DC RMS values.
As both the period and duty cycle of the PWM waveform can be controlled, the choice of generated
waveform is extremely flexible. In the PWM Output Mode, the PT0CCLR bit has no effect on the
PWM operation. Both of the CCRA and CCRP registers are used to generate the PWM waveform,
one register is used to clear the internal counter and thus control the PWM waveform frequency,
while the other one is used to control the duty cycle. The PWM waveform frequency and duty cycle
can therefore be controlled by the values in the CCRA and CCRP registers.
An interrupt flag, one for each of the CCRA and CCRP, will be generated when a compare match
occurs from either Comparator A or Comparator P. The PT0OC bit in the PTM0C1 register is used
to select the required polarity of the PWM waveform while the two PT0IO1 and PT0IO0 bits are
used to enable the PWM output or to force the PTM0 output pin to a fixed high or low level. The
PT
0POL bit is used to reverse the polarity of the PWM output waveform.
10-bit PTM, PWM Mode, Edge-aligned Mode
CCRP
1~1023
0
Pe�iod
1~102�
1024
D�t�
CCRA
If f
SYS
=
16
MHz,
PTM
0 clock source select f
SYS
/4, CCRP = 512 and CCRA = 128,
The PTM0 PWM output frequency = (f
SYS
/4) /
512
= f
SYS
/2048 =
7.8125
kHz, duty = 128/512 = 25%,
If the Duty value defined by the CCRA register is equal to or greater than the Period value, then the
PWM output duty is 100%.
Содержание BS82B12A-3
Страница 33: ...Rev 1 20 33 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...
Страница 34: ...Rev 1 20 34 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...
Страница 35: ...Rev 1 20 35 January 23 2015 BS82B12A 3 BS82C16A 3 BS82D20A 3 Touch Key 8 Bit Flash MCU with LED LCD Driver ...