Example 1-Wire pin configuration

[marcoramirezcastro]

I compiled and ran the MAX32650FTHR example for 1-Wire communication and I was not able to see the 1-Wire line move.

The SDK provides the following function to configure and initialize the 1-Wire pin: MXC_OWM_Init(&owm_cfg);

Upon further examination I noticed that it calls the MXC_GPIO_Config(&gpio_cfg_owm) function passing the gpio_cfg_owm structure.

this structure configures the wrong settings for the MAX32650 device:

const mxc_gpio_cfg_t gpio_cfg_owm = { MXC_GPIO0, (MXC_GPIO_PIN_6 | MXC_GPIO_PIN_7), MXC_GPIO_FUNC_ALT2,
                                      MXC_GPIO_PAD_NONE, MXC_GPIO_VSSEL_VDDIO, MXC_GPIO_DRVSTR_0 };

as per the user guide the alternate function should be set to 1 instead of 2.

Other configuration may not be applied as well during setup using MXC_OWM_Init() such as the use of external pull up.

I fixed on my application by running 'MXC_OWM_Init()` first and sequentially reconfiguring the GPIO for the 1-Wire pin on the MAX32650FTHR.

A Working example:

#include <stdio.h>
#include "mxc_errors.h"
#include "owm.h"
#include "gpio.h"
#include "mxc_delay.h"

int main(void)
{
    int retval;
    
    printf("***** 1-Wire Reset Pulse Test *****\n");
    printf("This example sends a reset pulse and checks for a presence response\n");
    printf("Connect 1-Wire pin, VCC, and GND to the target\n");
    printf("\n\n");

    // Initialize the OWM configuration structure
    mxc_owm_cfg_t owm_cfg;
    owm_cfg.int_pu_en = 1; // Enable internal pull-up
    owm_cfg.ext_pu_mode = MXC_OWM_EXT_PU_UNUSED; // Ensure external pull-up is off
    owm_cfg.long_line_mode = 0;





    // Initialize the OWM module with the specified configuration
    MXC_OWM_Init(&owm_cfg);

    // Configure GPIO for 1-Wire
    mxc_gpio_cfg_t gpio_cfg = {
        .port = MXC_GPIO1,
        .mask = (MXC_GPIO_PIN_31),
        .pad = MXC_GPIO_PAD_STRONG_PULL_UP, // Set pad to pull-up
        .func = MXC_GPIO_FUNC_ALT1,
        .vssel = MXC_GPIO_VSSEL_VDDIOH,
        .drvstr = MXC_GPIO_DRVSTR_3
    };
    MXC_GPIO_Config(&gpio_cfg);


    // Send a reset pulse and check for a presence response
    MXC_Delay(MXC_DELAY_SEC(5));
    retval = MXC_OWM_Reset();

    if (retval == 0) {
        printf("No presence pulse detected. No device is present on the bus.\n");
        
    } else if (retval == 1) {
        printf("Presence pulse detected. Device is present on the bus.\n");
    } else {
        printf("Error during reset pulse. Error code: %d\n", retval);
    }

    // Deinitialize the OWM module
    MXC_OWM_Shutdown();

    return 0;
}