topic Re: kSCTIMER_Out_* doesn't work except for kSCTIMER_Out_2 and kSCTIMER_Out_4 in LPC Microcontrollers

kSCTIMER_Out_* doesn't work except for kSCTIMER_Out_2 and kSCTIMER_Out_4

jren68 — Thu, 11 Oct 2018 00:57:29 GMT

I am looking at the sctimer_simple_pwm example provided for lpc54018.

According to the pin table for UM11079. for J11 area, the Sctimer output and pin correspondence are

Index Pin SCTimer_OUT

1 2_2 6

2 3_28 2

3 3_14 4

4 3_10 3

....

The provided example is

#define DEMO_FIRST_SCTIMER_OUT kSCTIMER_Out_4
#define DEMO_SECOND_SCTIMER_OUT kSCTIMER_Out_2
int main(void)
{
sctimer_config_t sctimerInfo;
sctimer_pwm_signal_param_t pwmParam;
uint32_t event;
uint32_t sctimerClock;
/* Board pin, clock, debug console init */
/* attach 12 MHz clock to FLEXCOMM0 (debug console) */
CLOCK_AttachClk(BOARD_DEBUG_UART_CLK_ATTACH);
BOARD_InitPins();
BOARD_BootClockFROHF96M();
BOARD_InitDebugConsole();
sctimerClock = SCTIMER_CLK_FREQ;
SCTIMER_GetDefaultConfig(&sctimerInfo);
/* Initialize SCTimer module */
SCTIMER_Init(SCT0, &sctimerInfo);
/* Configure first PWM with frequency 24kHZ from first output */
pwmParam.output = DEMO_FIRST_SCTIMER_OUT;
pwmParam.level = kSCTIMER_HighTrue;
pwmParam.dutyCyclePercent = 50;
if (SCTIMER_SetupPwm(SCT0, &pwmParam, kSCTIMER_CenterAlignedPwm, 24000U, sctimerClock, &event) == kStatus_Fail)
{
return -1;
}
/* Configure second PWM with different duty cycle but same frequency as before */
pwmParam.output = DEMO_SECOND_SCTIMER_OUT;
pwmParam.level = kSCTIMER_LowTrue;
pwmParam.dutyCyclePercent = 20;
if (SCTIMER_SetupPwm(SCT0, &pwmParam, kSCTIMER_CenterAlignedPwm, 24000U, sctimerClock, &event) == kStatus_Fail)
{
return -1;
}
/* Start the timer */
SCTIMER_StartTimer(SCT0, kSCTIMER_Counter_L);
while (1)
{
}
}

And it worked.

However, if I change kSCTIMER_Out_4 into kSCTIMER_Out_6 or kSCTIMER_Out_3, and plug the LED into the corresponding pinholes, the LED is not flickering.

Why only kSCTIMER_Out_4 and kSCTIMER_Out_2 works? How may I use the rest of the pinholes? (I need a third pinhole to PWM a tricolor LED)

Thanks,

Jenny

Re: kSCTIMER_Out_* doesn't work except for kSCTIMER_Out_2 and kSCTIMER_Out_4

jren68 — Thu, 11 Oct 2018 16:52:20 GMT

It turns out in the board/src/pin_mux

in BOARD_InitPins()

you need to define something like

port2_pin2_config if you wanna use the SCTimer_out_6 P2_2 correspond to

check line 120-140 for examples of P3_14 (SCTimer_out_4) and P3_28(SCTimer_out_2)

Re: kSCTIMER_Out_* doesn't work except for kSCTIMER_Out_2 and kSCTIMER_Out_4

kerryzhou — Fri, 12 Oct 2018 05:52:32 GMT

Hi Jenny,

Yes, if you want to change the STC output pin, you also need to modify the pin_mux BOARD_InitPins function.

You need to define P2_2 and P3_10 FUNC to SCT output function.

So, now, when you define the according pin configuration, do you make it works?

const uint32_t port2_pin2_config = (
    IOCON_PIO_FUNC3 |                                        /* Pin is configured as SCT0_OUT4 */
    IOCON_PIO_MODE_INACT |                                   /* No addition pin function */
    IOCON_PIO_INV_DI |                                       /* Input function is not inverted */
    IOCON_PIO_DIGITAL_EN |                                   /* Enables digital function */
    IOCON_PIO_INPFILT_OFF |                                  /* Input filter disabled */
    IOCON_PIO_SLEW_STANDARD |                                /* Standard mode, output slew rate control is enabled */
    IOCON_PIO_OPENDRAIN_DI                                   /* Open drain is disabled */
);
IOCON_PinMuxSet(IOCON, 2u, 2u, port2_pin2_config );
const uint32_t port3_pin10_config = (
    IOCON_PIO_FUNC1 |                                        /* Pin is configured as SCT0_OUT2 */
    IOCON_PIO_MODE_INACT |                                   /* No addition pin function */
    IOCON_PIO_INV_DI |                                       /* Input function is not inverted */
    IOCON_PIO_DIGITAL_EN |                                   /* Enables digital function */
    IOCON_PIO_INPFILT_OFF |                                  /* Input filter disabled */
    IOCON_PIO_SLEW_STANDARD |                                /* Standard mode, output slew rate control is enabled */
    IOCON_PIO_OPENDRAIN_DI                                   /* Open drain is disabled */
);
IOCON_PinMuxSet(IOCON, PORT3_IDX, 10u, port3_pin10_config );

If you still have problem about it, please kindly let me know.

Have a great day,
Kerry

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