stepped modulator working

lib/stepped.c

@@ -0,0 +1,69 @@
+#include "stepped.h"
+
+int steps = 12;
+int current_step = 0;
+int reset = 0;
+int twoup = 0;
+int down = 0;
+
+int vsteps[12] = {0};
+
+void stepped_init(void){
+    current_step = 0;
+    reset = 0;
+    twoup = 0;
+    down = 0;
+
+    float total_real_volts = (2.5f * 120.f / 24.9f);
+    float offset_real_volts = (2.5f * 120.f / 49.9f);
+
+    float one_volt = (float)(0xfff) / total_real_volts; // ~340 lsbs per volt
+    float half_range = offset_real_volts * one_volt;
+
+    for(int i=0; i<6; i++){
+        vsteps[i] = (int)(half_range - one_volt * i);
+    }
+    for(int i=6; i<12; i++){
+        vsteps[i] = (int)(half_range - one_volt * (i-12));
+    }
+}
+
+void stepped(float _steps, int _reset, int _twoup, int _down){
+    // perform reset first so we can wrap & then advance on simultaneous triggers
+    if(_reset != reset){
+        reset = _reset;
+        if(reset == 1){
+            current_step = 0;
+        }
+    }
+
+    // adjust playhead
+    if(_twoup != twoup){
+        twoup = _twoup;
+        if(twoup == 1){
+            current_step += 2;
+        }
+    }
+    if(_down != down){
+        down = _down;
+        if(down == 1){
+            current_step -= 1;
+        }
+    }
+
+    // wrap to steps
+    // don't use modulo to correctly handle negative values
+    // could just add steps, and then modulo for simpler solution
+    steps = 1 + (int)(_steps*11.999f); // [1,12)
+    while(current_step < 0){
+        current_step += steps;
+    }
+    while(current_step >= steps){
+        current_step -= steps;
+    }
+}
+
+int stepped_get(void){
+    // perform scaling
+    return vsteps[current_step];
+}

lib/stepped.h

@@ -0,0 +1,7 @@
+#pragma once
+
+void stepped_init(void);
+
+void stepped(float _steps, int _reset, int _twoup, int _down);
+
+int stepped_get(void);

ll/din.c

@@ -15,6 +15,7 @@ static const Pin ds[3] =
 
 static GPIO_InitTypeDef g;
 
+// TODO use EXTI instead of manual scanning
 void din_init(void){
     __HAL_RCC_GPIOB_CLK_ENABLE();
 

main.c

@@ -19,14 +19,15 @@
 #include "ll/adc.h"
 #include "ll/dac108.h"
 #include "ll/adda.h"
+#include "lib/stepped.h"
 
 /*
-density, C4, 2_in14
-steps, A5, 2_in5
-rotate, A6, 2_in6
 fold, A7, 1_in7
 id, B0, 1_in8
 offset, B1, 1_in9
+density, C4, 2_in14
+steps, A5, 2_in5
+rotate, A6, 2_in6
 
 MOSI, A0, SAI2_SD_B, AF10
 SCK, A2, SAI2_SCK_B, AF8
@@ -45,7 +46,7 @@ int main(void){
     status_led_fast(LED_SLOW); // slow blink until USB connection goes live
     status_led_set(1); // set status to ON to show sign of life straight away
 
-    printf("\n\nhi from crow!\n");
+    printf("\n\nhi from parafocus!\n");
 
     lights_init();
     lights_all(0);
@@ -67,6 +68,8 @@ int main(void){
     // ii_init( II_CROW );
     // Random_Init();
 
+    stepped_init();
+
     DAC_Init(32, 16); // 32 samples per block, 16 channels
     DAC_Start();
 
@@ -103,6 +106,12 @@ int main(void){
                 ADDA_set_val(i, ADC_get(i));
             }
         }
+
+        stepped(1.f, din_get(DIN_RESET), din_get(DIN_2UP), din_get(DIN_DOWN));
+        ADDA_set_val(0, stepped_get());
+        ADDA_set_val(1, 0x0); // set fine tune to zero position
+        // NOTE: chan 0 is main stepped cv, chan1 is fine tune
+
         // lights_set(0, din_get(DIN_RESET));
         // lights_set(1, din_get(DIN_DOWN));
         // lights_set(2, din_get(DIN_2UP));