Accessors Wiki | TockOS / Duktape2ToggleLED

After setting up Duktape2 and doing a Duktape2 Simple application, let's try toggling a LED.

As a start, we can try blinking a LED, see Duktape Eclipse ARM Cortex M4 -> Duktape Event Example:

/*
* Simple LED time test.
*/

function main() {

setInterval(function () {
LedControl.toggle(2);
}, 3000);
}

main();

To get something similar to work under the Hail board, we need to define a JavaScript function in Duktape that will invoke the appropriate C code.

In the long run, we need to use a module for this, but in the short term, let's just try to get something to work.

tock/userland/examples/ducktape/main-led.c contains:

/*
* Toggle a LED.
* See {$ACCESSORS_HOME}/wiki/TockOS/Duktape2ToggleLED
*/

#include "duktape.h"

#ifdef __ARM_EABI__
#include "console.h"
int _gettimeofday(struct timeval *tp, void *tzp) {
return 0;
}
#else
#define putstr(x) fprintf(stderr, "%s", x);
#endif

void ledcontrol_register(duk_context *ctx);

int main(int argc, char *argv[]) {
(void) argc; (void) argv; /* suppress warning */

putstr("duktape/main-led.c: start\n");
duk_context *ctx = duk_create_heap_default();

putstr("duktape/main-led.c: ledcontrol_register()\n");
ledcontrol_register(ctx);

duk_eval_string(ctx, "LedControl.toggle(2);");

duk_pop(ctx); /* pop eval result */

duk_destroy_heap(ctx);
putstr("duktape/main.c: done\n");
return 0;
}

[$[Get Code]]

tock/userland/examples/duktape/ledcontrol.c defines the LedControl.toggle() JavaScript function:

#include "duktape.h"

#ifdef __ARM_EABI__
#include <led.h>
#include <timer.h>
#endif

/**
* Register a JavaScript command to toggle a LED.
* @author Christopher Brooks
* @version $Id: ledcontrol.c 1231 2016-12-31 07:03:22Z cxh $
*/

static int ledcontrol_toggle(duk_context *ctx) {
const int led = duk_to_int(ctx, 0);

#ifdef __ARM_EABI__
// led_toggle(led);

// From tock/userland/examples/blink/main.c:
int num_leds = led_count();
for (int count = 0; ; count++) {
for (int i = 0; i < num_leds; i++) {
if (count & (1 << i)) {
led_on(i);
} else {
led_off(i);
}
}
delay_ms(250);
}

return 1;
#else
fprintf(stderr, "%s:%d led not supported?\n", __FILE__, __LINE__);
return DUK_RET_ERROR;
#endif

}

static duk_function_list_entry ledcontrol_funcs[] = {
{ "toggle", ledcontrol_toggle, 1 },
{ NULL, NULL, 0 }
};

void ledcontrol_register(duk_context *ctx) {
duk_push_global_object(ctx);
duk_push_object(ctx);
duk_put_function_list(ctx, -1, ledcontrol_funcs);
duk_put_prop_string(ctx, -2, "LedControl");
duk_pop(ctx);

}

[$[Get Code]]

tock/userland/example/duktape/Makefile-led.mk contains:

  C_SRCS := duktape.c ledcontrol.c main-led.c

Running

  make clean; make -f Makefile-led.mk TOCK_BOARD=hail program

compiles the demo and uploads it.

ealmac23:~ cxh$ tockloader listen
No serial port specified. Discovering attached serial devices...
Using "/dev/cu.usbserial-00001014 - Hail IoT Module - TockOS - Hail IoT Module - TockOS"
duktape/main-led.c: start
duktape/main-led.c: ledcontrol_regisduktape/main-led.c: start
duktape/main-led.c: ledcontrol_register()

[$[Get Code]]

Success: The LEDs blink!

The next step is Duktape2 RampJSDisplay