From ab6977f4685d0b88fc593273725a0db489c49a1e Mon Sep 17 00:00:00 2001
From: lonkaars <loek@pipeframe.xyz>
Date: Sun, 6 Feb 2022 10:12:17 +0100
Subject: working leds

---
 .gitignore |  2 ++
 src/main.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++--------------
 2 files changed, 67 insertions(+), 19 deletions(-)

diff --git a/.gitignore b/.gitignore
index a11e827..8b8427e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@ STM32-base
 STM32-base-STM32Cube
 bin
 obj
+.cache/
+compile_commands.json
diff --git a/src/main.c b/src/main.c
index 0365c80..dea5b7a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,30 +1,76 @@
 #include "stm32f0xx.h"
 
-// Quick and dirty delay
-static void delay (unsigned int time) {
-    for (unsigned int i = 0; i < time; i++)
-        for (volatile unsigned int j = 0; j < 2000; j++);
+#define PINOUT_LED_1 3
+#define PINOUT_LED_2 5
+#define PINOUT_LED_3 4
+#define PINOUT_LED_4 6
+
+const unsigned short leds[] = {PINOUT_LED_1, PINOUT_LED_2, PINOUT_LED_3, PINOUT_LED_4};
+
+/*
+ * This function configures the I/O-ports that are used by the I/O-shield. It
+ * uses register RCC_AHBENR to enable the clocks for the ports that are used,
+ * register  GPIOx_MODER to configure pins as input, analog or output and
+ * GPIOx_PUPDR to configure pull-up and pull-down resistors.
+ */
+void shieldConfig() {
+	// enable clock for I/O port D
+	RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
+
+	GPIOB->MODER &= ~((0b11 << (PINOUT_LED_1 * 2)) |\
+	                  (0b11 << (PINOUT_LED_2 * 2)) |\
+	                  (0b11 << (PINOUT_LED_3 * 2)) |\
+	                  (0b11 << (PINOUT_LED_4 * 2)));
+
+	GPIOB->MODER |= (0b01 << (PINOUT_LED_1 * 2)) |\
+	                (0b01 << (PINOUT_LED_2 * 2)) |\
+	                (0b01 << (PINOUT_LED_3 * 2)) |\
+	                (0b01 << (PINOUT_LED_4 * 2));
 }
 
-int main (void) {
-    // Turn on the GPIOC peripheral
-    RCC->AHBENR |= RCC_AHBENR_GPIOCEN;
+/*
+ * This function drives led <num> of the I/O-shield. <num> should be the number
+ * of the LED to drive (0, 1, 2 or 3) and <on> should be an integer with value
+ * 0 or 1 which indicates if the LED should be turned on (1) or off (0).
+ */
+void ledWrite(int num, int on) {
+	GPIOB->ODR &= ~(1 << leds[num]);
+	GPIOB->ODR |= (on << leds[num]);
+}
 
-    // Put pin 13 in general purpose output mode
-    GPIOC->MODER |= GPIO_MODER_MODER13_0;
+/*
+ * This function returns the status of the pushbutton of the I/O-shield.
+ * Return value 1 indicates that the button is currently pressed and return
+ * value 0 indicates that the button is currently not pressed.
+ */
+int buttonRead() {
+	return 0;
+}
 
-    while (1) {
-        // Reset the state of pin 13 to output low
-        GPIOC->BSRR = GPIO_BSRR_BR_13;
+void delay()
+{
+	int i;
+	for (i = 0; i < 50000; i++)
+	{
+		asm("nop");
+	}
+}
+int main()
+{
+	shieldConfig();
 
-        delay(500);
+	// RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
+	// GPIOA->MODER &= ~(1 << (PINOUT_LED_1 * 2 + 1));
+	// GPIOA->MODER |=  (1 << (PINOUT_LED_1 * 2));
 
-        // Set the state of pin 13 to output high
-        GPIOC->BSRR = GPIO_BSRR_BS_13;
+	// GPIOA_MODER &= ~(0 << (PINOUT_LED_1 * 2 + 1));
 
-        delay(500);
-    }
+	while (1)
+	{
+		for(int i = 0; i < 2 * 4; i++) {
+			ledWrite(i % 4, i >= 4);
 
-    // Return 0 to satisfy compiler
-    return 0;
+			delay();
+		}
+	}
 }
-- 
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