From 0de4e549d58fd11ec662b40a9d776a536d1b2b0d Mon Sep 17 00:00:00 2001
From: Jan-Henrik Bruhn <hi@jhbruhn.de>
Date: Mon, 11 May 2020 13:15:56 +0200
Subject: [PATCH] Fix onepole filter bug in processor resulting in wrong CV
 values

---
 stereo_mix/processor.cc  | 10 +++++-----
 stereo_mix/stereo_mix.cc | 26 ++++++++++++--------------
 2 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/stereo_mix/processor.cc b/stereo_mix/processor.cc
index 4be6cb4..d534a56 100644
--- a/stereo_mix/processor.cc
+++ b/stereo_mix/processor.cc
@@ -13,8 +13,8 @@ void Processor::Process(int16_t cvs[], uint16_t* outs)
   uint32_t value_r;
 
   // dirty low pass
-  this->cv_input_pan = ((cvs[0] - this->cv_input_pan) >> 3);
-  this->cv_input_vol = ((cvs[1] - this->cv_input_vol) >> 3);
+  this->cv_input_pan += ((cvs[0] - this->cv_input_pan) >> 4);
+  this->cv_input_vol += ((cvs[1] - this->cv_input_vol) >> 5);
 
   uint16_t pan_pot = (pan_offset + 32767L);
   uint16_t vol_pot = (vol_offset);
@@ -35,7 +35,7 @@ void Processor::Process(int16_t cvs[], uint16_t* outs)
   uint16_t vol_cv_absu16 = abs(vol_cv) << 1;
   uint16_t vol_cv_exp = Interpolate124(lut_linear_to_exp, vol_cv_absu16);
   uint16_t vol_cv_log = 65535 - InverseInterpolate124(lut_linear_to_exp, vol_cv_absu16);
-  uint32_t vol_cv_pre = (Mix(static_cast<uint16_t>(vol_cv_exp >> 1), vol_cv_log >> 1, log_exp_mix_cv) << 3) * 3;
+  uint32_t vol_cv_pre = (Mix(static_cast<uint16_t>(vol_cv_exp >> 1), vol_cv_log >> 1, log_exp_mix_cv) << 1) * 2;
   vol += vol_cv > 0 ? vol_cv_pre : -vol_cv_pre;
   vol *= !mute;
 
@@ -43,9 +43,9 @@ void Processor::Process(int16_t cvs[], uint16_t* outs)
 
   this->previous_vol = vol;
 
-  int32_t pan_cv = (cv_input_pan * static_cast<int32_t>(pan_att)) >> 15; // full attenuate gives 3x amplification :)
+  int32_t pan_cv = (cv_input_pan * static_cast<int32_t>(pan_att)) >> 15; // full attenuate gives 2x amplification :)
   pan_cv = Clip16(pan_cv);
-  int32_t pan = pan_pot + ((pan_cv << 3) * 4);
+  int32_t pan = pan_pot + ((pan_cv) * 2);
   pan = ClipU16(pan);
 
   value_l = (lut_left_sin_pan[pan >> 4] * vol) >> 16;
diff --git a/stereo_mix/stereo_mix.cc b/stereo_mix/stereo_mix.cc
index c84e995..d58862e 100644
--- a/stereo_mix/stereo_mix.cc
+++ b/stereo_mix/stereo_mix.cc
@@ -110,11 +110,11 @@ void HAL_ADC_ConvCpltCallback(ADC_HandleTypeDef* hadc)
 void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef* htim)
 {
   if (htim == &htim3) {
-    leds.Write();
+    leds.Write(); // 53571 Hz
     return;
   }
   if (htim == &htim6) {
-    WriteOutputs();
+    WriteOutputs(); // 4076 Hz
   }
 }
 }
@@ -133,7 +133,7 @@ void Init(void)
 
   HAL_NVIC_SetPriority(TIM3_IRQn, 0, 0);
   HAL_NVIC_EnableIRQ(TIM3_IRQn);
-  htim3.Init.Prescaler = 10;
+  htim3.Init.Prescaler = 8;
   htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
   htim3.Init.Period = 128;
   htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
@@ -143,9 +143,9 @@ void Init(void)
 
   HAL_NVIC_SetPriority(TIM6_IRQn, 1, 0);
   HAL_NVIC_EnableIRQ(TIM6_IRQn);
-  htim6.Init.Prescaler = 64;
+  htim6.Init.Prescaler = 47;
   htim6.Init.CounterMode = TIM_COUNTERMODE_UP;
-  htim6.Init.Period = 96; // 512 without optimize
+  htim6.Init.Period = 256; // 96 without optimize
   htim6.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
   htim6.Init.RepetitionCounter = 0;
   HAL_TIM_Base_Init(&htim6);
@@ -154,23 +154,20 @@ void Init(void)
   system_clock.Init();
 }
 
+uint16_t out[kNumChannels][2];
+
 void WriteOutputs(void)
 {
-  uint16_t out[kNumChannels][2];
-    DEBUG_ON
+  for (int i = 0; i < kNumChannels; i++) {
+    dacs.Write16(i, 0, out[i][0]);
+    dacs.Write16(i, 1, out[i][1]);
+  }
   for (int i = 0; i < kNumChannels; i++) {
     int16_t cvs[2];
     cvs[0] = 65535 - adc.cv_value(AdcChannel(ADC_CHANNEL_PAN_1 + i));
     cvs[1] = adc.cv_value(AdcChannel(ADC_CHANNEL_VOL_1 + i));
     processors[i].Process(cvs, out[i]);
   }
-  for (int i = 0; i < kNumChannels; i++) {
-    dacs.Write16(i, 0, out[i][0]);
-    //dacs.Write16(0, out[i][0]);
-    dacs.Write16(i, 1, out[i][1]);
-    //dacs[i + 4].Write16(1, out[i][1]);
-  }
-    DEBUG_OFF
 }
 
 int main(void)
@@ -179,6 +176,7 @@ int main(void)
   SystemClock_Config();
 
   Init();
+  ui.Init();
 
   while (true) {
     ui.DoEvents();