add bit counter program

Makefile

@@ -29,7 +29,11 @@ ifeq ($(shell test -d $(name) && echo "ok"),)
 	@false
 endif
 
-project: .check-name
+project:
+ifeq ($(strip $(name)), "")
+	@echo "error: project name must be set, ex: name=<project_name>"
+	@false
+endif
 	@./scripts/scaffold_project.bash $(name) $(SDK_VERSION)
 
 format: .check-name

bit_counter/CMakeLists.txt

@@ -0,0 +1,38 @@
+# Generated Cmake Pico project file
+
+cmake_minimum_required(VERSION 3.13)
+
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Pull in Raspberry Pi Pico SDK (must be before project)
+include($ENV{PICO_SDK_PATH}/external/pico_sdk_import.cmake)
+
+project(bit_counter C CXX ASM)
+
+# Initialise the Raspberry Pi Pico SDK
+pico_sdk_init()
+
+# Add executable. Default name is the project name, version 0.1
+
+add_executable(bit_counter main.c )
+
+pico_set_program_name(bit_counter "bit_counter")
+pico_set_program_version(bit_counter "0.1")
+
+# Modify the below lines to enable/disable output over UART/USB
+pico_enable_stdio_uart(bit_counter 0)
+pico_enable_stdio_usb(bit_counter 1)
+
+# Add the standard library to the build
+target_link_libraries(bit_counter
+        pico_stdlib)
+
+# Add the standard include files to the build
+target_include_directories(bit_counter PRIVATE
+        ${CMAKE_CURRENT_LIST_DIR}
+)
+
+pico_add_extra_outputs(bit_counter)
+

bit_counter/main.c

@@ -0,0 +1,187 @@
+#include <pico/printf.h>
+#include <pico/stdlib.h>
+#include <pico/malloc.h>
+#include <string.h>
+
+#define NB_LED_BAR_GPIO 10
+
+static const int LED_BAR_GPIO[NB_LED_BAR_GPIO] = {28, 27, 26, 22, 21, 20, 19, 18, 17, 16};
+
+typedef int led_state;
+enum LED_STATE { OFF, ON };
+
+typedef struct led led;
+struct led {
+    int gpio;
+    led_state state;
+};
+
+void set_led_state(led *l, int state) {
+    if (l != NULL) {
+        l->state = state;
+        gpio_put(l->gpio, l->state);
+    }
+}
+
+char* state_into_str(led_state state) {
+    switch (state) {
+    case ON:
+        return "ON";
+    case OFF:
+        return "OFF";
+    default:
+        return "OFF";
+    }
+}
+
+void init_led_bar(led leds[]) {
+    for (int i = 0; i < NB_LED_BAR_GPIO; i++, leds++) {
+        *leds = (led) {
+            .gpio = LED_BAR_GPIO[i], .state = OFF
+        };
+    }
+}
+
+
+void print_led_bar_state(led leds[]) {
+    for (int i = 0; i < NB_LED_BAR_GPIO; i++, leds++) {
+        char *state = state_into_str(leds->state);
+        char led_state[12];
+        sprintf(led_state, "%3s (%d)", state, leds->gpio);
+        if (i != NB_LED_BAR_GPIO - 1) {
+            strcat(led_state, " | ");
+        }
+        printf(led_state);
+    }
+    printf("\n");
+}
+
+/**
+ * Convert an integer into a 10 bits array (corresponding to the number of LED).
+ *
+ * It loops over the less to the most significant bit and for each bit, masks it with
+ * the value to find if the value bit is 0 or 1 and then store it in the bits array.
+ *
+ * Example:
+ * - value = 10 <=> 1010, i = 0
+ * - left shift one: 1 << i <=> 0001 << 0 = 1
+ * - mask the value with the shifted one: 1010 & 0001 = 0000
+ * - find the result by right shifting the masked value by i: 0 >> 0 <=> 0000 >> 0 = 0
+ * - i++
+ */
+int *int_into_bits(int value) {
+    int *bits = malloc(NB_LED_BAR_GPIO * sizeof(int));
+    for (int i = 0; i < NB_LED_BAR_GPIO; i++) {
+        int mask = 1 << i;
+        int masked_value = value & mask;
+        // the first led is the rightmost, so we start feeding the bit array by the end
+        bits[NB_LED_BAR_GPIO - 1 - i] = masked_value >> i;
+    }
+    return bits;
+}
+
+void blink_failed(uint gpio, uint32_t delay_ms) {
+    for (;;) {
+        gpio_put(gpio, false);
+        sleep_ms(delay_ms);
+
+        gpio_put(gpio, true);
+        sleep_ms(delay_ms);
+    }
+}
+
+void set_default_led_state(led_state state) {
+    gpio_put(PICO_DEFAULT_LED_PIN, state == ON);
+}
+
+void run_bit_counter(led leds[], uint nb_bit, uint32_t delay_ms) {
+    // nothing to do with 0 bit, entering in failed mode.
+    if (nb_bit <= 0) {
+        blink_failed(PICO_DEFAULT_LED_PIN, 500);
+        return;
+    }
+
+    // healthcheck
+    set_default_led_state(ON);
+
+    // `nb_bit` can't be greater than the number of leds
+    if (nb_bit > NB_LED_BAR_GPIO) {
+        nb_bit = NB_LED_BAR_GPIO;
+    }
+
+    // compute the maximum value
+    int const max_value = 2 << nb_bit - 1;
+    int current_value = 1;
+
+    for (;;) {
+        if (current_value == max_value) {
+            current_value = 1;
+            led *p_leds = leds;
+
+            for (int i = 0; i < NB_LED_BAR_GPIO; i++, p_leds++) {
+                set_led_state(p_leds, OFF);
+            }
+
+            set_default_led_state(OFF);
+            sleep_ms(delay_ms);
+            set_default_led_state(ON);
+
+            continue;
+        }
+
+        led *p_leds = leds;
+        int *bits = int_into_bits(current_value);
+
+        int *p_bits = bits;
+        for (int i = 0; i < NB_LED_BAR_GPIO; i++, p_leds++, p_bits++) {
+            set_led_state(p_leds, *p_bits ? ON : OFF);
+        }
+        free(bits);
+
+        print_led_bar_state(leds);
+        current_value++;
+
+        sleep_ms(delay_ms);
+    }
+}
+
+/* Initialize needed GPIO. */
+void init_gpio(void) {
+#ifdef PICO_DEFAULT_LED_PIN
+    gpio_init(PICO_DEFAULT_LED_PIN);
+    gpio_set_dir(PICO_DEFAULT_LED_PIN, GPIO_OUT);
+#endif
+
+    for (int i = 0; i < NB_LED_BAR_GPIO; i++) {
+        gpio_init(LED_BAR_GPIO[i]);
+        gpio_set_dir(LED_BAR_GPIO[i], GPIO_OUT);
+    }
+}
+
+/**
+ * Bit counter program with a LED bar.
+ *
+ * Increment a value, convert it in bit and display the value
+ * on the LED bar (1: led on, 0 led OFF) until it reaches max value.
+ *
+ * BA-SIC. But it's fun to see the result.
+ *
+ * When the max value is reached, the program restarts.
+ *
+ * You can customize the incrementation speed and the number of bit to display
+ * (max = number of led on the bar available) by changing the `run_bit_counter`
+ * arguments.
+ *
+ * Ex: display only 4 bits (4 leds) with increment speed of 50 ms:
+ * run_bit_counter(leds, 4, 50);
+ */
+int main() {
+    stdio_init_all();
+    init_gpio();
+
+    led leds[NB_LED_BAR_GPIO] = {};
+    init_led_bar(leds);
+    print_led_bar_state(leds);
+
+    run_bit_counter(leds, 11, 50);
+}

templates/main.c.tpl

@@ -1,4 +1,4 @@
-#include <stdio.h>
+#include <pico/printf.h>
 #include <pico/stdlib.h>
 
 int main()
@@ -6,7 +6,7 @@ int main()
     stdio_init_all();
 
     while (true) {
-        printf("<prog_name> is running...\n");
+        stdio_printf("<prog_name> is running...\n");
         sleep_ms(1000);
     }
 }