[Solved] Clarification on total usable PWM channels

[davidt.jones-19]

Posted on October 09, 2014 at 21:29

I am trying to maximize the number of unique 16-bit PWM outputs that I can use simultaneously on the SPC560P40L1CEFAR (64 pins).  I have gathered the following information from the specification, and some of it appears to be conflicting.

1 Flex PWM unit

8 complementary or independent channels

4 PWM submodules

PWMX pin can optionally output a third PWM signal from each submodule

I count 10 PWM output channels though:

    A0, A1 A2, B0, B1, B2, B3, X0, X1, X2;

    B2 and X2 are both only available on pin 52

Which output channels correspond to which submodules?  And which channels cannot produce unique PWM signals?

I also noticed a paradox on page 24 of the SPC560P (34L and 40L) specification.  On the same page it says:

    Channels not used for PWM generation can be used for input capture functions.

A few lines down it then says:

    Capture capability for PWMA, PWMB, and PWMX channels not supported

Does this mean I need to use timer pins for input capture instead of the PWM pins?

#pwm #spc56

[Erwan YVIN]

Posted on November 24, 2014 at 14:25

Hello David ,

Here is an answer from a PWM Expert

sorry for the late answer

''The FlexPWM doesn’t support input capture function, on the datasheet there is a wrong information. In order to perform input capture you should use eTimer as you mentioned.

INFO:

Sub-mod 0: PA0, PB0,PX0

Sub-mod 1: PA1, PB1,PX1

Sub-mod 2: PA2, PB2,PX2

Sub-mod 3: PA3, PB3,PX3  -  On 64pins PA3 and PX3 are not available

PB0 (not PB2) and PX2 are both only available on pin 52…so you can use only 9 PWM signals simultaneously…''

           Best Regards

                                Erwan

[davidt.jones-19]

Posted on November 24, 2014 at 20:33

Thank you for the reply.  I chose to scale down number of channels to be safe, but this confirms my conservative assumptions.