16. GPIO¶

16.1. Overview¶

This example explains how to configure GPIO.

16.2. Usage Steps¶

Compile and flash customer_app/sdk_app_gpio.
In the serial console, use gpio-func <pinnum> <inputmode> <pullup> <pulldown> to configure a GPIO pin. input_mode configures whether the pin is an input (and otherwise, an output), and pullup and pulldown respectively configures the pull-up and pull-down states. For instance, gpio-func 8 0 0 0 configures gpio pin 8 as output without pull-up / pull-down.

Use gpio-set <pinnum> <val> to configure the voltage level of a pin (an output pin).

Use gpio-get <pinnum> to look up the voltage level of a pin.

16.3. Code Examples¶

Implementation of gpio-func

if (5 != argc) {
    printf("Usage: %s 24 1 1 0\r\n  set GPIO24 to input with pullup\r\n",
            argv[0]
    );
    return;
}
ionum = atoi(argv[1]);
inputmode = atoi(argv[2]);
pullup = atoi(argv[3]);
pulldown = atoi(argv[4]);
if (ionum < 0 || inputmode < 0 || pullup < 0 || pulldown < 0) {
    puts("Illegal arg\r\n");
    return;
}
printf("GPIO%d is set %s with %s pullup %s pulldown\r\n",
        ionum,
        inputmode ? "input" : "output",
        pullup ? "Active" : "null",
        pulldown ? "Active" : "null"
);
if (inputmode) {
    bl_gpio_enable_input(ionum, pullup ? 1 : 0, pulldown ? 1 : 0);
} else {
    bl_gpio_enable_output(ionum, pullup ? 1 : 0, pulldown ? 1 : 0);
}

It receives inputs from the serial console, and pass them as parameters to bl_gpio_enable_input(uint8, uint8, uint8) or bl_gpio_enable_output(uint8, uint8, uint8) to configure the corresponding GPIO pin.

Implementation of gpio-set

if (3 != argc) {
    printf("Usage: %s 24 1\r\n  set GPIO24 output to high\r\n",
            argv[0]
    );
    return;
}
ionum = atoi(argv[1]);
val = atoi(argv[2]);
if (ionum < 0 || val < 0) {
    puts("Illegal arg\r\n");
    return;
}
printf("GPIO%d is set to %s\r\n",
    ionum,
    val ? "high" : "lo"
);
bl_gpio_output_set(ionum, val ? 1 : 0);

It receives inputs from the CLI and pass them to bl_gpio_output_set(uint8, uint8).

Implementation of gpio-get

if (2 != argc) {
     printf("Usage: %s 24\r\n  get GPIO24 value\r\n",
             argv[0]
     );
     return;
 }
 ionum = atoi(argv[1]);
 if (ionum < 0) {
     puts("Illegal arg\r\n");
     return;
 }
 ret = bl_gpio_input_get(ionum, &val);
 printf("GPIO%d val is %s\r\n",
     ionum,
     0 == ret ? (val ? "high" : "low") : "Err"
 );

It receives inputs from the CLI and pass them to bl_gpio_input_get(uint8, uint8*)

In customer_app/sdk_app_gpio/sdk_app_gpio/main.c, the function static void _cli_init() invokes gpio_cli_init() to initialize GPIO-related commands.