diff --git a/stereo_mix/drivers/dac.h b/stereo_mix/drivers/dac.h
index 5b10c0e..0cf411a 100644
--- a/stereo_mix/drivers/dac.h
+++ b/stereo_mix/drivers/dac.h
@@ -1,9 +1,9 @@
 #pragma once
 
 #include "peripherals.h"
-#include "stm32f030x8.h"
 #include "stmlib/stmlib.h"
 #include <stm32f0xx_hal.h>
+#include <stm32f0xx_ll_spi.h>
 
 namespace stereo_mix {
 
@@ -17,6 +17,9 @@ class Dac { // MCP4xx2 dac implementation
     __HAL_RCC_GPIOB_CLK_ENABLE();
     __HAL_RCC_SPI1_CLK_ENABLE();
 
+    HAL_NVIC_SetPriority(SPI1_IRQn, 0, 0);
+    HAL_NVIC_EnableIRQ(SPI1_IRQn);
+
     ssGpioPort = ssGpioPort_;
     ssGpioPin = ssGpioPin_;
     // init SS/CS/RST GPIO
@@ -46,10 +49,11 @@ class Dac { // MCP4xx2 dac implementation
     hspi1.Init.CLKPolarity = SPI_POLARITY_HIGH;
     hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
     hspi1.Init.NSS = SPI_NSS_SOFT;
-    hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_4;
+    hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
     hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
     hspi1.Init.CRCPolynomial = 7;
     HAL_SPI_Init(&hspi1);
+    SPI1->CR1 |= SPI_CR1_SPE; // this is required only once
   };
 
   void Write16(uint8_t channel, uint16_t value, uint8_t gain, uint8_t buffered)
@@ -70,13 +74,11 @@ class Dac { // MCP4xx2 dac implementation
     value |= gain << 13;     // set gain
     value |= 1 << 12;        // shutdown always set to 1
 
-    HAL_GPIO_WritePin(ssGpioPort, ssGpioPin, GPIO_PIN_RESET);
-    HAL_SPI_Transmit(&hspi1, (uint8_t*)&value, 1, HAL_MAX_DELAY);
-    //SPI_I2S_SendData16(SPI1, value); // MSB first, specified in config
-    /*while (HAL_SPI_GetState(&hspi1) & HAL_SPI_STATE_BUSY) {
-      asm("nop");
-    }*/
-    HAL_GPIO_WritePin(ssGpioPort, ssGpioPin, GPIO_PIN_SET);
+    ssGpioPort->BRR |= ssGpioPin;
+    SPI1->DR = value;
+    while ((SPI1->SR & (SPI_SR_TXE | SPI_SR_BSY)) != SPI_SR_TXE)
+      ;
+    ssGpioPort->BSRR |= ssGpioPin;
   };
 
   void Write16(uint8_t channel, uint16_t value)
diff --git a/stereo_mix/drivers/leds.h b/stereo_mix/drivers/leds.h
index fb4ed2b..66f5097 100644
--- a/stereo_mix/drivers/leds.h
+++ b/stereo_mix/drivers/leds.h
@@ -35,7 +35,12 @@ class Leds {
     pwm_counter &= 0x1ff; // equals to if(pwm_counter > 512) pwm_counter = 0;
     blink_counter++;
     if(blink_counter > 0x2000) blink_counter = 0;
+#ifdef DEBUG_PIN
+    for (size_t i = 0; i < kNumChannels - 1; i++) {
+#else
     for (size_t i = 0; i < kNumChannels; i++) {
+
+#endif
       bool in_blink_phase = blink_counter > (0x2000 / 2) || !blinking[i];
       if (intensities[0] && lut_led_gamma[intensities[i]] >= pwm_counter && in_blink_phase) {
         kGpioPorts[i]->BSRR |= kGpioPins[i];
diff --git a/stereo_mix/drivers/peripherals.c b/stereo_mix/drivers/peripherals.c
index 4444e0a..162ecac 100644
--- a/stereo_mix/drivers/peripherals.c
+++ b/stereo_mix/drivers/peripherals.c
@@ -6,6 +6,10 @@ SPI_HandleTypeDef hspi1 = { .Instance = SPI1 };
 TIM_HandleTypeDef htim3 = { .Instance = TIM3 };
 TIM_HandleTypeDef htim6 = { .Instance = TIM6 };
 
+void SPI1_IRQHandler(void)
+{
+  HAL_SPI_IRQHandler(&hspi1);
+}
 void DMA1_Channel1_IRQHandler(void)
 {
   HAL_DMA_IRQHandler(&hdma1_channel1);
diff --git a/stereo_mix/stereo_mix.cc b/stereo_mix/stereo_mix.cc
index df914d9..0ce00a1 100644
--- a/stereo_mix/stereo_mix.cc
+++ b/stereo_mix/stereo_mix.cc
@@ -1,3 +1,7 @@
+
+#define ENABLE_DEBUG_PIN
+#include "drivers/debug_pin.h"
+
 #include "drivers/adc.h"
 #include "drivers/dac.h"
 #include "drivers/leds.h"
@@ -142,9 +146,9 @@ void Init(void)
 
   HAL_NVIC_SetPriority(TIM6_IRQn, 1, 0);
   HAL_NVIC_EnableIRQ(TIM6_IRQn);
-  htim6.Init.Prescaler = 192;
+  htim6.Init.Prescaler = 64;
   htim6.Init.CounterMode = TIM_COUNTERMODE_UP;
-  htim6.Init.Period = 512;
+  htim6.Init.Period = 128; //256; //512;
   htim6.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
   htim6.Init.RepetitionCounter = 0;
   HAL_TIM_Base_Init(&htim6);
@@ -155,6 +159,7 @@ void Init(void)
 
 void WriteOutputs(void)
 {
+  DEBUG_ON
   for (int i = 0; i < kNumChannels; i++) {
     uint16_t out[2];
     int16_t cvs[2];
@@ -166,6 +171,7 @@ void WriteOutputs(void)
     dacs[i].Write16(1, out[1]);
     dacs[i + 4].Write16(1, out[1]);
   }
+  DEBUG_OFF
 }
 
 int main(void)
@@ -176,9 +182,6 @@ int main(void)
   Init();
 
   while (true) {
-
     ui.DoEvents();
-
-//    WriteOutputs();
   }
 }