added sample code

Signed-off-by: Sahaj Sarup <[email protected]>

Makefile

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+BOARD ?= 96b_carbon
+
+CONF_FILE = prj.conf
+
+include ${ZEPHYR_BASE}/Makefile.inc

README.md

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+# 96Boards Carbon Basic Multi Thread Example
+## Overview
+
+This example demonstrates spawning of multiple threads using K_THREAD_DEFINE.
+
+The example works by spawning  three threads, each controlling a separate LED
+on the 96Boards Carbon board. Each of these LEDs (USR1, USR2 and BT) have
+their individual loop control and timing logic defined by separate functions.
+
+- blink1() controls the USR1 LED that has a 100ms sleep cycle
+- blink2() controls the USR2 LED that has a 1000ms sleep cycle
+- blink3() controls the BT LED that increases sleep by 100ms every cycle
+	 upto 600ms and then resets to 100ms
+
+
+Each thread is then defined at compile time using K_THREAD_DEFINE.
+
+Apart from that, a main() thread is also present that provides a basic shell
+based on the shell sample at zephyr_base/samples/subsys/shell/shell/
+
+The sample has been written keeping the 96Boards Carbon in mind, feel free to
+modify it accordingly.
+***
+
+## Building
+
+### COMPILE
+```shell
+$ cd zephyr_base/path/to/sample/zephyr_multithread_blinky
+$ make
+```
+
+### Flashing via OTG
+```shell
+$ sudo dfu-util -d [0483:df11] -a 0 -D outdir/96b_carbon/zephyr.bin -s 0x08000000
+```
+### Flash via UART
+```shell
+$ sudo stm32flash -b 115200 -g 0x0 -w outdir/96b_carbon/zephyr.bin /dev/ttyUSB0
+```

prj.conf

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+CONFIG_PRINTK=y
+CONFIG_CONSOLE_SHELL=y
+CONFIG_KERNEL_SHELL=y
+CONFIG_OBJECT_TRACING=y
+CONFIG_THREAD_MONITOR=y
+CONFIG_INIT_STACKS=y

src/Makefile

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+obj-y = main.o

src/main.c

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+#include <zephyr.h>
+#include <device.h>
+#include <gpio.h>
+#include <misc/printk.h>
+#include <shell/shell.h>
+
+/* size of stack area used by each thread */
+#define STACKSIZE 128
+
+/* scheduling priority used by each thread */
+#define PRIORITY 7
+
+#define MY_SHELL_MODULE "sample_module"
+
+/*-----shell code fom <zephyr_base>/samples/subsys/shell/shell/------*/
+static int shell_cmd_ping(int argc, char *argv[])
+{
+	ARG_UNUSED(argc);
+	ARG_UNUSED(argv);
+
+	printk("pong\n");
+
+	return 0;
+}
+
+static int shell_cmd_params(int argc, char *argv[])
+{
+	int cnt;
+
+	printk("argc = %d\n", argc);
+	for (cnt = 0; cnt < argc; cnt++) {
+		printk("  argv[%d] = %s\n", cnt, argv[cnt]);
+	}
+	return 0;
+}
+
+static struct shell_cmd commands[] = {
+	{ "ping", shell_cmd_ping, NULL },
+	{ "params", shell_cmd_params, "print argc" },
+	{ NULL, NULL, NULL }
+};
+
+void main(void)
+{
+	SHELL_REGISTER(MY_SHELL_MODULE, commands);
+}
+/*-------------------------------------------------------------------*/
+
+
+void blink1(void)
+{
+	int cnt = 0;
+	struct device *gpioa;
+
+	gpioa = device_get_binding("GPIOA");
+	gpio_pin_configure(gpioa, 15, GPIO_DIR_OUT);
+	while (1) {
+		gpio_pin_write(gpioa, 15, (cnt + 1) % 2);
+		k_sleep(100);
+		cnt++;
+	}
+}
+
+void blink2(void)
+{
+	int cnt = 0;
+	struct device *gpiod;
+
+	gpiod = device_get_binding("GPIOD");
+	gpio_pin_configure(gpiod, 2, GPIO_DIR_OUT);
+	while (1) {
+		gpio_pin_write(gpiod, 2, cnt % 2);
+		k_sleep(1000);
+		cnt++;
+	}
+}
+
+void blink3(void)
+{
+	int cnt = 0, cnt2 = 0, sleep = 100;
+	struct device *gpiob;
+
+	gpiob = device_get_binding("GPIOB");
+	gpio_pin_configure(gpiob, 5, GPIO_DIR_OUT);
+	while (1) {
+		while (cnt2 != 5) {
+			gpio_pin_write(gpiob, 5, cnt2 % 2);
+			k_sleep(sleep);
+			sleep += 100;
+			cnt2++;
+		}
+		cnt2 = 0;
+		sleep = 100;
+	}
+}
+
+K_THREAD_DEFINE(blink1_id, STACKSIZE, blink1, NULL, NULL, NULL,
+		PRIORITY, 0, K_NO_WAIT);
+K_THREAD_DEFINE(blink2_id, STACKSIZE, blink2, NULL, NULL, NULL,
+		PRIORITY, 0, K_NO_WAIT);
+K_THREAD_DEFINE(blink3_id, STACKSIZE, blink3, NULL, NULL, NULL,
+		PRIORITY, 0, K_NO_WAIT);