From 20e188ab3c70f0f2f2502019f1f7cb3b05952321 Mon Sep 17 00:00:00 2001
From: lonkaars <loek@pipeframe.xyz>
Date: Tue, 8 Feb 2022 19:56:32 +0100
Subject: practicum done

---
 src/main.c | 37 ++++++++++++++++++++++++++++++-------
 1 file changed, 30 insertions(+), 7 deletions(-)

diff --git a/src/main.c b/src/main.c
index 38a4fd8..8fc4dba 100644
--- a/src/main.c
+++ b/src/main.c
@@ -56,6 +56,9 @@ void shieldConfig() {
 	GPIOB->PUPDR &= ~(0b11 << (PINOUT_BTN * 2));
 	GPIOB->PUPDR |=  (0b01 << (PINOUT_BTN * 2));
 
+	ADC1->SMPR &= ~(0x7);
+	// ADC1->SMPR |=  (0x7);
+
 	// calirate ADC1
   ADC1->CR |= ADC_CR_ADCAL;
   while ((ADC1->CR & ADC_CR_ADCAL));
@@ -83,12 +86,11 @@ void ledWrite(int num, int on) {
  * value 0 indicates that the button is currently not pressed.
  */
 int buttonRead() {
-	return (GPIOB->IDR & (1 << PINOUT_BTN)) > 0;
+	return (GPIOB->IDR & (1 << PINOUT_BTN)) == 0;
 }
 
 /*
  * Read potmeter value as analog value between 0 and 2^12 - 1
- * TODO: increase measurement sensitivity
  */
 unsigned int potRead() {
 	ADC1->CHSELR = (1 << PINOUT_POT);
@@ -108,25 +110,46 @@ int mod(int a, int b) {
   return m < 0 ? (b < 0) ? m - b : m + b : m;
 }
 
+typedef enum {
+	up_idle = 0,
+	pressed = 1,
+	down_idle = 2
+} button_state;
+
 int main() {
 	shieldConfig();
 
 	uint8_t reverse = 0;
 	uint8_t led = 0;
+	button_state state = up_idle;
 
 	while (1) {
-		for(int j = 0; j < 4; j++) ledWrite(j, 0);
-		ledWrite(potRead(), 1);
+		uint8_t button_now = buttonRead();
+
+		switch(state) {
+			case up_idle: {
+				state = button_now ? pressed : up_idle;
+				break;
+			}
+			case pressed: {
+				state = button_now ? down_idle : up_idle;
+				break;
+			}
+			case down_idle: {
+				state = button_now ? down_idle : up_idle;
+				break;
+			}
+		}
 		
-		continue;
+		if (state == pressed) reverse ^= 1;
 
-		reverse = buttonRead();
 		for(int j = 0; j < 4; j++) ledWrite(j, 0);
 
+		// calculate next led index
 		led = mod(led + ((2 * reverse) - 1), 4);
 
 		ledWrite(led, 1);
-		// ledWrite(3, (ADC1->ISR & ADC_ISR_ADRDY) == 0 ? 0 : 1);
+
 		delay(100 + 300 * potRead());
 	}
 }
-- 
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