From f875ab2a70afe023c8457cdd8814e146814d2b7e Mon Sep 17 00:00:00 2001
From: lonkaars <loek@pipeframe.xyz>
Date: Tue, 8 Feb 2022 19:25:29 +0100
Subject: worky analog

---
 src/main.c | 57 ++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 44 insertions(+), 13 deletions(-)

diff --git a/src/main.c b/src/main.c
index a357387..38a4fd8 100644
--- a/src/main.c
+++ b/src/main.c
@@ -24,7 +24,9 @@ const unsigned short leds[] = {PINOUT_LED_1, PINOUT_LED_2, PINOUT_LED_3, PINOUT_
  */
 void shieldConfig() {
 	// enable clock for I/O ports A and B
-	RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
+	RCC->AHBENR |= RCC_AHBENR_GPIOAEN | RCC_AHBENR_GPIOBEN;
+	// enable clock for the ADC peripheral
+	RCC->APB2ENR |= RCC_APB2ENR_ADC1EN;
 
 	// clear mode register configuration bits
 	GPIOB->MODER &= ~((0b11 << (PINOUT_LED_1 * 2)) |\
@@ -32,6 +34,9 @@ void shieldConfig() {
 	                  (0b11 << (PINOUT_LED_3 * 2)) |\
 	                  (0b11 << (PINOUT_LED_4 * 2)) |\
 										(0b11 << (PINOUT_BTN * 2)));
+	GPIOA->MODER &= ~((0b11 << (PINOUT_DISP_CLK * 2)) |\
+	                  (0b11 << (PINOUT_DISP_DIO * 2)) |\
+	                  (0b11 << (PINOUT_POT * 2)));
 
 	// set output mode register configuration bits
 	// 0b00 -> input mode (reset state)
@@ -43,10 +48,23 @@ void shieldConfig() {
 	                (0b01 << (PINOUT_LED_3 * 2)) |\
 	                (0b01 << (PINOUT_LED_4 * 2)) |\
 									(0b00 << (PINOUT_BTN * 2));
+	GPIOA->MODER |= (0b01 << (PINOUT_DISP_CLK * 2)) |\
+	                (0b01 << (PINOUT_DISP_DIO * 2)) |\
+	                (0b11 << (PINOUT_POT * 2));
 
 	// pull-up resistor for button
 	GPIOB->PUPDR &= ~(0b11 << (PINOUT_BTN * 2));
 	GPIOB->PUPDR |=  (0b01 << (PINOUT_BTN * 2));
+
+	// calirate ADC1
+  ADC1->CR |= ADC_CR_ADCAL;
+  while ((ADC1->CR & ADC_CR_ADCAL));
+
+	// enable ADC V_REFINT
+  ADC->CCR |= ADC_CCR_VREFEN;
+
+	// enable ADC1
+  ADC1->CR |= ADC_CR_ADEN;
 }
 
 /*
@@ -68,13 +86,21 @@ int buttonRead() {
 	return (GPIOB->IDR & (1 << PINOUT_BTN)) > 0;
 }
 
-void delay()
-{
-	int i;
-	for (i = 0; i < 50000; i++)
-	{
-		asm("nop");
-	}
+/*
+ * Read potmeter value as analog value between 0 and 2^12 - 1
+ * TODO: increase measurement sensitivity
+ */
+unsigned int potRead() {
+	ADC1->CHSELR = (1 << PINOUT_POT);
+	ADC1->CR |= ADC_CR_ADSTART;
+	while (ADC1->CR & ADC_CR_ADSTART);
+	uint16_t result = ADC1->DR;
+	ADC1->CR |= ADC_CR_ADSTP;
+	return result;
+}
+
+void delay(int amount) {
+	for (int i = 0; i < 500 * amount; i++) asm("nop");
 }
 
 int mod(int a, int b) {
@@ -82,20 +108,25 @@ int mod(int a, int b) {
   return m < 0 ? (b < 0) ? m - b : m + b : m;
 }
 
-int main()
-{
+int main() {
 	shieldConfig();
 
 	uint8_t reverse = 0;
 	uint8_t led = 0;
-	while (1)
-	{
+
+	while (1) {
+		for(int j = 0; j < 4; j++) ledWrite(j, 0);
+		ledWrite(potRead(), 1);
+		
+		continue;
+
 		reverse = buttonRead();
 		for(int j = 0; j < 4; j++) ledWrite(j, 0);
 
 		led = mod(led + ((2 * reverse) - 1), 4);
 
 		ledWrite(led, 1);
-		delay();
+		// ledWrite(3, (ADC1->ISR & ADC_ISR_ADRDY) == 0 ? 0 : 1);
+		delay(100 + 300 * potRead());
 	}
 }
-- 
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