CCS/TMS570LC4357: pwm Notification Compare

Valentino Papandrea

Part Number: TMS570LC4357
Other Parts Discussed in Thread: HALCOGEN

Tool/software: Code Composer Studio

Hello,

I'm trying to switch my clock from an RTI interrupt based routine to a pwm interrupt one. In order to do this I've set up all the necessary settings in HalCoGen and as far as the creation of the pwm and of linked interrupts I'm doing all right. I would like to know if anyone has any hints or code examples (Code Composer Projects) on how to create a proper notification function (pwmNotification) and moreover on which registers to use to compare the "notification" value from this function in order to trigger some actions at a given moment in time based on the periodicity of the pwm. I am trying to replicate the rtiNotification and rtiCompare type of functions into the pwm setting.

thank you

over 7 years ago

0 QJ Wang over 7 years ago

TI__Guru**** 200246 points

Hello Valentino,

You can add a counter in pwmNotification() as a flag and use this flag as a condition to switch your code to other function or to start a SW interrupt. But you can not trigger another INT (for example another IRQ) in pwmNotification(). Hercules MCU doesn't support the nested interrupt.

ePWM supports seven interrupt events: TBCTR=0, TBPRD, or both; CMPA, CMPB (up or down). The interrupt can be generated after the number of events (1 event, 2 event or 3 events) occur, this is configured by ETPS register.

The best and simplest way is to use RTI as the timer.

0 Valentino Papandrea over 7 years ago in reply to QJ Wang

Prodigy 190 points

can I find more insight on how ePWM events work on the board manual ? or other documents ?

0 QJ Wang over 7 years ago in reply to Valentino Papandrea

TI__Guru**** 200246 points

Hello Valentino,

Please refer to 17.2.8 Event-Trigger (ET) Submodule in TRM SPNU607

Arm-based microcontrollers

Arm-based microcontrollers forum

CCS/TMS570LC4357: pwm Notification Compare