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question about the PWM peripheral

Question asked by McRock on Apr 21, 2013
Latest reply on May 22, 2013 by MaheshN

hi all

in the manual named "ADSP-214xx_hwr_r1-0", page 464. or 8-24. we have such a description.


"The PWM_SYNCENx bits in this register can be used to start the counter without

enabling the outputs through PWM_EN. So when PWM_ENx is asserted, the

4 PWM outputs are automatically synced to the initially programmed

period. In most cases, all SYNC bits can be initialized to zero, enabling the

PWM_ENx bits of the four PWM groups at the same time synchronizes the

four groups.

The PWM sync enable feature allows programs to enable the PWM_SYNCENx

bits to independently start the main counter without enabling the corresponding

PWM module using the PWM_ENx bits. To synchronize different

groups, enable the corresponding group’s PWM_ENx bit at the same time. In

order to stop the counter both the PWM_DISx and PWM_SYNCDISx bits should

be set in this register."


1). what i understand is that PWM_SYNCENx controls the counter and PWM_ENx controls the output, but when you enables PWM_ENx the counter is automatically set to initially programmed period. is this correct?

2). this initially programmed period i reckon should be 0. for the counter always starts at 0. is this correct? or how can i change it?

3). instead of having 1 control bit for both counter and output, you choose to have 2 bit to control them individually. And the behaviors of these 2 approach are identical to me. what is the reason for this? can you give me an example of such a application that require this feature?