diff --git a/firmware/main.c b/firmware/main.c
index d0f1ba8..57ad143 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -18,9 +18,11 @@
 // Constants
 #define FLOW_CONVERSION_FACTOR 5.5  // L/min = Hz / 5.5 (Adjust for ZJ-S401)
 
-#define ADC_UP_BTN_MAX     200  // Button 1 range: 50..200  (center ~93)
-#define ADC_UP_BTN_MIN      20
-#define ADC_DOWN_BTN_MAX    15  // Button 2 range: 0..15    (should read ~0)
+// Button ladder 
+#define ADC_UP_BTN_MAX      15   // UP connects direct to GND -> ~0V -> ADC ~0
+#define ADC_UP_BTN_MIN      0
+#define ADC_DOWN_BTN_MAX    200  // DOWN connects via 1k -> ~0.45V -> ADC ~93
+#define ADC_DOWN_BTN_MIN    50
 
 #define DEBOUNCE_DELAY_MS   200
 
@@ -48,31 +50,38 @@ void Init_Hardware(void) {
     // 1. Enable Clocks for GPIOA, GPIOC, GPIOD, ADC, AFIO
     RCC->APB2PCENR |= RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD | RCC_APB2Periph_ADC1 | RCC_APB2Periph_AFIO;
 
+    // [NEW FIX] Set ADC Clock Prescaler to DIV8 (48MHz / 8 = 6MHz). Must be <= 14MHz!
+    RCC->CFGR0 &= ~RCC_ADCPRE;        // Clear prescaler bits
+    RCC->CFGR0 |= RCC_ADCPRE_DIV8;    // Set to divide by 8
+
     // 2. Configure ALARM_TRIGGER Output (PA2) - Push-Pull
     GPIOA->CFGLR &= ~(0xF << (4 * ALARM_PIN));
     GPIOA->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP) << (4 * ALARM_PIN);
-    GPIOA->BSHR = (1 << (16 + ALARM_PIN)); // Default to ALARM STATE (Low = MOSFET OFF)
+    GPIOA->BSHR = (1 << (16 + ALARM_PIN)); 
 
     // 3. Configure FLOW_PULSE_MCU Input (PD6) - Pull-up
     GPIOD->CFGLR &= ~(0xF << (4 * FLOW_PIN));
     GPIOD->CFGLR |= (GPIO_CNF_IN_PUPD) << (4 * FLOW_PIN);
-    GPIOD->BSHR = (1 << FLOW_PIN); // Enable pull-up
+    GPIOD->BSHR = (1 << FLOW_PIN); 
 
-    // Setup EXTI on PD6 (CH32V003 has single EXTICR, 2 bits per pin, Port D = 0b11)
-    AFIO->EXTICR |= (0b11 << (FLOW_PIN * 2));   // PD6: Port D=0b11, bits [13:12]
-    EXTI->INTENR |= (1 << FLOW_PIN);             // Enable EXTI interrupt on line 6
-    EXTI->FTENR  |= (1 << FLOW_PIN);             // Falling edge trigger
-    NVIC_EnableIRQ(EXTI7_0_IRQn);                // Enable interrupt in NVIC
+    AFIO->EXTICR |= (0b11 << (FLOW_PIN * 2));   
+    EXTI->INTENR |= (1 << FLOW_PIN);             
+    EXTI->FTENR  |= (1 << FLOW_PIN);             
+    NVIC_EnableIRQ(EXTI7_0_IRQn);                
 
-    // 4. Configure BUTTON_ADC Input (PC4 / AIN2) - Analog mode (no pull)
+    // 4. Configure BUTTON_ADC Input (PC4 / AIN2) - Analog mode
     GPIOC->CFGLR &= ~(0xF << (4 * BUTTON_PIN));
 
     // Setup ADC
-    ADC1->CTLR2 |= ADC_ADON;       // Turn on ADC
-    ADC1->RSQR3 = 2;               // PC4 is ADC Channel 2 (AIN2)
-    ADC1->SAMPTR2 = 7 << (3 * 2);  // Max sampling time for CH2
+    ADC1->CTLR2 |= ADC_ADON;       
+    ADC1->RSQR3 = 2;               
+    ADC1->SAMPTR2 = 7 << (3 * 2);  
 
-    ADC1->CTLR2 |= ADC_RSTCAL;     // Reset & calibrate
+    // [NEW FIX] Must configure EXTTRIG and EXTSEL for SWSTART to actually work
+    ADC1->CTLR2 |= ADC_EXTSEL;     // Select SWSTART trigger (111)
+    ADC1->CTLR2 |= ADC_EXTTRIG;    // Enable external trigger
+
+    ADC1->CTLR2 |= ADC_RSTCAL;     
     while(ADC1->CTLR2 & ADC_RSTCAL);
     ADC1->CTLR2 |= ADC_CAL;
     while(ADC1->CTLR2 & ADC_CAL);
@@ -146,19 +155,19 @@ int main() {
         }
 
         // --- 3. BUTTON HANDLING (ADC Resistor Ladder) ---
-        // Thresholds match actual voltages: no-press ~1023, BTN1 ~93, BTN2 ~0.
         uint16_t adc_val = Read_ADC();
 
         if ((current_time - last_button_time) > (DEBOUNCE_DELAY_MS * DELAY_US_TIME * 1000)) {
+            
             if (adc_val >= ADC_UP_BTN_MIN && adc_val <= ADC_UP_BTN_MAX) {
-                // Button 1: voltage divider 10k+1k -> ~0.30V -> ADC ~93
+                // Button UP pressed
                 threshold_ml_min += 100;
                 last_button_time = current_time;
                 printf("[SET] Threshold increased to: %lu mL/min\r\n", threshold_ml_min);
                 Update_Display(flow_rate_ml_min, threshold_ml_min);
             }
-            else if (adc_val <= ADC_DOWN_BTN_MAX) {
-                // Button 2: direct to GND -> ~0V -> ADC ~0
+            else if (adc_val >= ADC_DOWN_BTN_MIN && adc_val <= ADC_DOWN_BTN_MAX) {
+                // Button DOWN pressed
                 if (threshold_ml_min >= 100) threshold_ml_min -= 100;
                 last_button_time = current_time;
                 printf("[SET] Threshold decreased to: %lu mL/min\r\n", threshold_ml_min);