Hi,
I'm having trouble getting a PWM signal on PIO1_14 (for SCT0_7)
Maybe it the some clock issue, however I'm not sure. I hope you might have a hint of somekind.
Below is code (as you can see it is using the library from lpc chip. )
Using embOS as operating system.
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#define SCT_PWM LPC_SCT0 /* Use SCT0 for PWM */
#define SCT_PWM_PIN_OUT 7 /* COUT0_7 Generate square wave */
#define SCT_PWM_OUT 0
void Init_and_start_PWM(void)
{
| Chip_SYSCTL_PowerDown(SYSCTL_POWERDOWN_SCTPLL_PD); |
| Chip_Clock_SetSCTPLLSource(SYSCTL_PLLCLKSRC_MAINOSC); |
| Chip_Clock_SetupSCTPLL(5,2); |
| Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_SCTPLL_PD); |
| /* Wait for PLL to lock */ |
| while (!Chip_Clock_IsSCTPLLLocked()) {} |
#define SCT_PWM_RATE 200000 /* PWM frequency 200 KHz */
Chip_SCTPWM_Init(LPC_SCT0);
| Chip_SCTPWM_SetRate(LPC_SCT0, SCT_PWM_RATE); |
| /* Enable SWM clock before altering SWM */ |
| Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM); |
Chip_SWM_EnableFixedPin(SWM_FIXED_SCT0_OUT7);
Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);
| Chip_SCTPWM_SetOutPin(LPC_SCT0, SCT_PWM_OUT, SCT_PWM_PIN_OUT); |
| /* Start with 50% duty cycle */ |
| Chip_SCTPWM_SetDutyCycle(LPC_SCT0, SCT_PWM_OUT, Chip_SCTPWM_PercentageToTicks(LPC_SCT0, 50)); |
| Chip_SCTPWM_Start(LPC_SCT0); |
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Starting the PWM (just above), I only measure the pin goes high, and there it stays. Breaking the code shows that the counters are running in SCT.
BR Jørgen Busch
