Hi
I have just build a project that runs on the FRDM-K22F and generates a 1kHz 20% PWM signal on PTA4 (FTM0_CH1) on J1-10. At the same time it generates a timer overflow interrupt which toggles the red LED (PTA1) on J2-4.
It is attached as binary and the registers can be viewed by using the memory display command on the UART command line interface.
The code I use is
PWM_INTERRUPT_SETUP pwm_setup;
pwm_setup.int_type = PWM_INTERRUPT;
pwm_setup.pwm_mode = (PWM_SYS_CLK | PWM_PRESCALER_16 | PWM_EDGE_ALIGNED); // clock PWM timer from the system clock with /16 pre-scaler
pwm_setup.int_handler = PWM_IRQ;
pwm_setup.pwm_reference = (_TIMER_0 | 1); // timer module 0, channel 1
pwm_setup.pwm_frequency = PWM_FREQUENCY(1000, 16); // generate 1000Hz on PWM output
pwm_setup.pwm_value = _PWM_PERCENT(20, pwm_setup.pwm_frequency); // 20% PWM (high/low)
fnConfigureInterrupt((void *)&pwm_setup); // enter configuration for PWM test
and the interrupt handler is
static void PWM_IRQ(void)
{
_TOGGLE_PORT(A, PORTA_BIT1);
}
This is non-complimentary PWM mode (although I don't think this makes any difference).
To get the interrupt from the basic PWM operation it is only necessary to enter and enable the interrupt handler (in vector table and NVIC) and enable the interrupt with FTM_SC_TOIE in the FTMx_SC register.
To clear the interrupt each time it fires one does
FTMx_SC &= ~(FTM_SC_TOF); // clear interrupt (read when set and write 0 to reset)
if your driver interface doesn't do it for you (the uTasker PWM driver interface does all work that otherwise requires detailed hardware knowledge).
Regards
Mark
The required output.
I am not able to get output on both channels simulataneosuly.
