MSPM0C1104: Pin on the fly input / output switching

I try that with this test code but PA27 switch not to input :

#include "ti_msp_dl_config.h"
#include <stdint.h>

#define PORTA     GPIO_GRP_0_PORT
#define CP0_PIN   GPIO_GRP_0_CP0_PIN     // PA26 (anode LED1)
#define CP1_IOMUX GPIO_GRP_0_CP1_IOMUX   // PA27 (vrije pin)
#define CP2_PIN   GPIO_GRP_0_CP2_PIN     // PA28 (cathode LED1)
#define CP0_IOMUX GPIO_GRP_0_CP0_IOMUX
#define CP2_IOMUX GPIO_GRP_0_CP2_IOMUX

static inline void dly(volatile uint32_t n){ while(n--) __NOP(); }

int main(void)
{
    SYSCFG_DL_init();

    for(;;)
    {
        /* ---------- ON: wissel IOMUX INPUT -> OUTPUT (glitchvrij) ---------- */

        // 0) vrije pin echt vrij (kies 1 van de 2 regels)
        DL_GPIO_initDigitalInput(CP1_IOMUX);      // PA27 = input, no pull (SysCfg)
        // DL_GPIO_initAnalog(CP1_IOMUX);         // (alternatief) PA27 = Analog (zeker high-Z)

        // 1) PRELOAD OUT-latch (pads nog géén output!)
        DL_GPIO_clearPins(PORTA, CP2_PIN);        // PA28 latch = LOW (cathode)
        DL_GPIO_setPins  (PORTA, CP0_PIN);        // PA26 latch = HIGH (anode)
        dly(50);                                   // korte guard

        // 2) IOMUX → DigitalOutput (runtime switch)
        DL_GPIO_initDigitalOutput(CP2_IOMUX);     // PA28 wordt nu echt LOW
        DL_GPIO_initDigitalOutput(CP0_IOMUX);     // PA26 wordt nu echt HIGH

        dly(600000);                               // ~0.6 s AAN (LED1 zou nu alleen moeten branden)

        /* ---------- OFF: terug naar INPUT (IOMUX terug) ---------- */

        DL_GPIO_initDigitalInput(CP0_IOMUX);      // PA26 terug naar input
        DL_GPIO_initDigitalInput(CP2_IOMUX);      // PA28 terug naar input
        // (optioneel) latches wissen, heeft geen effect op inputs:
        DL_GPIO_clearPins(PORTA, CP0_PIN);
        DL_GPIO_clearPins(PORTA, CP2_PIN);

        dly(300000);                               // ~0.3 s UIT
    }
}

Diego,

Thanks for the info, if I look to figure 9-1  I can leave the pin to output and need to
activate the shutdown ti switch the pin to Hi Z.
I have to look for the shutdown command.

best regards,

rob Keij

Hi Rob,
You are correct. However, the MSPM0C1103/4 devices don't support wake from SHUTDOWN mode. I would recommend any other mode like STANDBY0/1.

Best Regards,

Diego Abad

Hi Diego,

Ok I try and you right for every function change of the pin and change via IOMUX  needs a complete restart.
So the simple design with the charlieplex led is unusable. I was hoping to use the MSPM0C1104.
I stil not understand that there is no possibility to switch a pin from output to input or floating.
I was sure this should be possible and produce 100 pcba's :(

I mark you first answer as "This resolved my issue"    (This answered my issue)

Thanks,

best regards,

Rob keij

Hi Rob,
Let me see if I can get a deeper explanation on the topic.

Best Regards,

Diego Abad

#include "ti_msp_dl_config.h"
#include <stdint.h>

#define PA26_MASK  DL_GPIO_PIN_26
#define PA27_MASK  DL_GPIO_PIN_27
#define PA28_MASK  DL_GPIO_PIN_28

static inline void dly(volatile uint32_t n){ while(n--) __NOP(); }

/* -------------------------------------------------------------- */
/* Tri-state en output helpers – alléén GPIO-registers             */
/* -------------------------------------------------------------- */

static inline void make_input_hiz(uint32_t mask)
{
    // maak pin input (DOE bit = 0)
    GPIOA->DOE31_0 &= ~mask;
}

static inline void make_output(uint32_t mask)
{
    // maak pin output (DOE bit = 1)
    GPIOA->DOE31_0 |= mask;
}

/* -------------------------------------------------------------- */
/* Eén LED aansturen: A=anode, C=kathode, F=vrije pin             */
/* -------------------------------------------------------------- */

static void drive_one(uint32_t A_mask, uint32_t C_mask, uint32_t F_mask, uint32_t on_ticks)
{
    // alles los
    make_input_hiz(PA26_MASK | PA27_MASK | PA28_MASK);

    // vrije pin blijft input (high-Z)
    make_input_hiz(F_mask);

    // vooraf: kathode laag, anode hoog
    GPIOA->DOUT31_0 &= ~C_mask;
    GPIOA->DOUT31_0 |=  A_mask;

    // outputs activeren
    make_output(C_mask);
    make_output(A_mask);

    dly(on_ticks);

    // terug los
    make_input_hiz(A_mask | C_mask);
}

/* -------------------------------------------------------------- */
/* main – sequentieel alle zes LED-combinaties                    */
/* -------------------------------------------------------------- */

int main(void)
{
    SYSCFG_DL_init();

    while (1)
    {
        drive_one(PA26_MASK, PA28_MASK, PA27_MASK, 500000); // L1
        drive_one(PA27_MASK, PA28_MASK, PA26_MASK, 500000); // L2
        drive_one(PA26_MASK, PA27_MASK, PA28_MASK, 500000); // L3
        drive_one(PA28_MASK, PA26_MASK, PA27_MASK, 500000); // L5
        drive_one(PA28_MASK, PA27_MASK, PA26_MASK, 500000); // L6
        drive_one(PA27_MASK, PA26_MASK, PA28_MASK, 500000); // L7
        dly(300000);
    }
}