Concerto M3 Timer PWM problem

Hi Nir,

Check with this sample project:

0207.epwm_timer_interrupts.zip

Regards,

Gautam

Hello Gautam,

The sample projects uses the C28 DSP to generate PWMs. I can do that also with no problem.

What I am trying to do is generate PWM signals from the M3,using timer PWM mode ( CCP ).

Any idea ?

Thanks Igor,

Finally I see an output !!!

I have one more smaller problem now, I am trying to get a lower frequency of PWM by prescaling the timer clock.

TimerPrescaleSet(TIMER0_BASE,TIMER_B, 4); // 4 for example

But there is no change in the output...

Can you help me with that ?

Hello!

Perhaps just the sequence of operations to be performed correctly:

TimerControlLevel(TIMER0_BASE, TIMER_B, true);
TimerLoadSet(TIMER0_BASE, TIMER_B, SysCtlClockGet()/4000);
TimerMatchSet(TIMER0_BASE, TIMER_B, SysCtlClockGet()/8000);

Regards,

Igor

No... :(

Also tried 

TimerLoadSet(TIMER0_BASE, TIMER_B, SysCtlClockGet()/4000);

TimerPrescaleSet(TIMER0_BASE,TIMER_B, 4);

TimerMatchSet(TIMER0_BASE, TIMER_B, SysCtlClockGet()/8000);

TimerPrescaleMatchSet(TIMER0_BASE,TIMER_B, 4);

But there is no change in output, I still see 4KHz frequency, 50% Duty cycle.

Well, 

I guess the Prescaler only works in 16-bit mode of the timer, it is written in timer.c driver file.

Thank you.

Hello!

The devil knows...Your case is a 16-bit just if to refer to timer.c:

//*****************************************************************************
//! Configures the timer(s).
//!
//! \param ulBase is the base address of the timer module.
//! \param ulConfig is the configuration for the timer.
//!
//! This function configures the operating mode of the timer(s). The timer
//! module is disabled before being configured, and is left in the disabled
//! state. The configuration is specified in \e ulConfig as one of the
//! following values:
//!
//! - \b TIMER_CFG_32_BIT_OS - 32-bit one-shot timer
//! - \b TIMER_CFG_32_BIT_OS_UP - 32-bit one-shot timer that counts up instead
//! of down (not available on all parts)
//! - \b TIMER_CFG_32_BIT_PER - 32-bit periodic timer
//! - \b TIMER_CFG_32_BIT_PER_UP - 32-bit periodic timer that counts up instead
//! of down (not available on all parts)
//! - \b TIMER_CFG_32_RTC - 32-bit real time clock timer
//! - \b TIMER_CFG_16_BIT_PAIR - Two 16-bit timers
//!
//! When configured for a pair of 16-bit timers, each timer is separately
//! configured. The first timer is configured by setting \e ulConfig to
//! the result of a logical OR operation between one of the following values
//! and \e ulConfig:
//!
//! - \b TIMER_CFG_A_ONE_SHOT - 16-bit one-shot timer
//! - \b TIMER_CFG_A_ONE_SHOT_UP - 16-bit one-shot timer that counts up instead
//! of down (not available on all parts)
//! - \b TIMER_CFG_A_PERIODIC - 16-bit periodic timer
//! - \b TIMER_CFG_A_PERIODIC_UP - 16-bit periodic timer that counts up instead
//! of down (not available on all parts)
//! - \b TIMER_CFG_A_CAP_COUNT - 16-bit edge count capture
//! - \b TIMER_CFG_A_CAP_TIME - 16-bit edge time capture
//! - \b TIMER_CFG_A_PWM - 16-bit PWM output
//!
//! Similarly, the second timer is configured by setting \e ulConfig to
//! the result of a logical OR operation between one of the corresponding
//! \b TIMER_CFG_B_* values and \e ulConfig.

It seems "TimerPrescaleSet" must work...It is necessary to sort out...

Regards,

Igor

Well , 

I guess you are right, it is 16 bit mode with PWM so it must work.

But 

Hi Nir,

I am also using same CPU( F28M35h52C1 ). I faced a problem in SSI( SSI configured as SPI in Cortex M3 ) 

Please take a look into this problem.

http://e2e.ti.com/support/microcontrollers/c2000/f/171/t/275586.aspx

Thanks in Advance

Thirumoorthy.R