implemented sketch for Teensy with 4x neopixel, 2x DAC (control volta…

…ge), and 2x digital output (gate)
robertoostenveld · Jan 15, 2020 · 83e2c30 · 83e2c30
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diff --git a/teensy_cvgate_mcp4725_neopixel/colormap.h b/teensy_cvgate_mcp4725_neopixel/colormap.h
@@ -0,0 +1,10 @@
+/*
+ * This is the "turbo" colormap, which resembles the MATLAB "jet" colormap
+ * See https://ai.googleblog.com/2019/08/turbo-improved-rainbow-colormap-for.html
+ * 
+ * It consists of 256 RGB triplets with values between 0 and 1.
+ */
+
+float R[] = {0.18995,0.19483,0.19956,0.20415,0.20860,0.21291,0.21708,0.22111,0.22500,0.22875,0.23236,0.23582,0.23915,0.24234,0.24539,0.24830,0.25107,0.25369,0.25618,0.25853,0.26074,0.26280,0.26473,0.26652,0.26816,0.26967,0.27103,0.27226,0.27334,0.27429,0.27509,0.27576,0.27628,0.27667,0.27691,0.27701,0.27698,0.27680,0.27648,0.27603,0.27543,0.27469,0.27381,0.27273,0.27106,0.26878,0.26592,0.26252,0.25862,0.25425,0.24946,0.24427,0.23874,0.23288,0.22676,0.22039,0.21382,0.20708,0.20021,0.19326,0.18625,0.17923,0.17223,0.16529,0.15844,0.15173,0.14519,0.13886,0.13278,0.12698,0.12151,0.11639,0.11167,0.10738,0.10357,0.10026,0.09750,0.09532,0.09377,0.09287,0.09267,0.09320,0.09451,0.09662,0.09958,0.10342,0.10815,0.11374,0.12014,0.12733,0.13526,0.14391,0.15323,0.16319,0.17377,0.18491,0.19659,0.20877,0.22142,0.23449,0.24797,0.26180,0.27597,0.29042,0.30513,0.32006,0.33517,0.35043,0.36581,0.38127,0.39678,0.41229,0.42778,0.44321,0.45854,0.47375,0.48879,0.50362,0.51822,0.53255,0.54658,0.56026,0.57357,0.58646,0.59891,0.61088,0.62233,0.63323,0.64362,0.65394,0.66428,0.67462,0.68494,0.69525,0.70553,0.71577,0.72596,0.73610,0.74617,0.75617,0.76608,0.77591,0.78563,0.79524,0.80473,0.81410,0.82333,0.83241,0.84133,0.85010,0.85868,0.86709,0.87530,0.88331,0.89112,0.89870,0.90605,0.91317,0.92004,0.92666,0.93301,0.93909,0.94489,0.95039,0.95560,0.96049,0.96507,0.96931,0.97323,0.97679,0.98000,0.98289,0.98549,0.98781,0.98986,0.99163,0.99314,0.99438,0.99535,0.99607,0.99654,0.99675,0.99672,0.99644,0.99593,0.99517,0.99419,0.99297,0.99153,0.98987,0.98799,0.98590,0.98360,0.98108,0.97837,0.97545,0.97234,0.96904,0.96555,0.96187,0.95801,0.95398,0.94977,0.94538,0.94084,0.93612,0.93125,0.92623,0.92105,0.91572,0.91024,0.90463,0.89888,0.89298,0.88691,0.88066,0.87422,0.86760,0.86079,0.85380,0.84662,0.83926,0.83172,0.82399,0.81608,0.80799,0.79971,0.79125,0.78260,0.77377,0.76476,0.75556,0.74617,0.73661,0.72686,0.71692,0.70680,0.69650,0.68602,0.67535,0.66449,0.65345,0.64223,0.63082,0.61923,0.60746,0.59550,0.58336,0.57103,0.55852,0.54583,0.53295,0.51989,0.50664,0.49321,0.47960};
+float G[] = {0.07176,0.08339,0.09498,0.10652,0.11802,0.12947,0.14087,0.15223,0.16354,0.17481,0.18603,0.19720,0.20833,0.21941,0.23044,0.24143,0.25237,0.26327,0.27412,0.28492,0.29568,0.30639,0.31706,0.32768,0.33825,0.34878,0.35926,0.36970,0.38008,0.39043,0.40072,0.41097,0.42118,0.43134,0.44145,0.45152,0.46153,0.47151,0.48144,0.49132,0.50115,0.51094,0.52069,0.53040,0.54015,0.54995,0.55979,0.56967,0.57958,0.58950,0.59943,0.60937,0.61931,0.62923,0.63913,0.64901,0.65886,0.66866,0.67842,0.68812,0.69775,0.70732,0.71680,0.72620,0.73551,0.74472,0.75381,0.76279,0.77165,0.78037,0.78896,0.79740,0.80569,0.81381,0.82177,0.82955,0.83714,0.84455,0.85175,0.85875,0.86554,0.87211,0.87844,0.88454,0.89040,0.89600,0.90142,0.90673,0.91193,0.91701,0.92197,0.92680,0.93151,0.93609,0.94053,0.94484,0.94901,0.95304,0.95692,0.96065,0.96423,0.96765,0.97092,0.97403,0.97697,0.97974,0.98234,0.98477,0.98702,0.98909,0.99098,0.99268,0.99419,0.99551,0.99663,0.99755,0.99828,0.99879,0.99910,0.99919,0.99907,0.99873,0.99817,0.99739,0.99638,0.99514,0.99366,0.99195,0.98999,0.98775,0.98524,0.98246,0.97941,0.97610,0.97255,0.96875,0.96470,0.96043,0.95593,0.95121,0.94627,0.94113,0.93579,0.93025,0.92452,0.91861,0.91253,0.90627,0.89986,0.89328,0.88655,0.87968,0.87267,0.86553,0.85826,0.85087,0.84337,0.83576,0.82806,0.82025,0.81236,0.80439,0.79634,0.78823,0.78005,0.77181,0.76352,0.75519,0.74682,0.73842,0.73000,0.72140,0.71250,0.70330,0.69382,0.68408,0.67408,0.66386,0.65341,0.64277,0.63193,0.62093,0.60977,0.59846,0.58703,0.57549,0.56386,0.55214,0.54036,0.52854,0.51667,0.50479,0.49291,0.48104,0.46920,0.45740,0.44565,0.43399,0.42241,0.41093,0.39958,0.38836,0.37729,0.36638,0.35566,0.34513,0.33482,0.32473,0.31489,0.30530,0.29599,0.28696,0.27824,0.26981,0.26152,0.25334,0.24526,0.23730,0.22945,0.22170,0.21407,0.20654,0.19912,0.19182,0.18462,0.17753,0.17055,0.16368,0.15693,0.15028,0.14374,0.13731,0.13098,0.12477,0.11867,0.11268,0.10680,0.10102,0.09536,0.08980,0.08436,0.07902,0.07380,0.06868,0.06367,0.05878,0.05399,0.04931,0.04474,0.04028,0.03593,0.03169,0.02756,0.02354,0.01963,0.01583};
+float B[] = {0.23217,0.26149,0.29024,0.31844,0.34607,0.37314,0.39964,0.42558,0.45096,0.47578,0.50004,0.52373,0.54686,0.56942,0.59142,0.61286,0.63374,0.65406,0.67381,0.69300,0.71162,0.72968,0.74718,0.76412,0.78050,0.79631,0.81156,0.82624,0.84037,0.85393,0.86692,0.87936,0.89123,0.90254,0.91328,0.92347,0.93309,0.94214,0.95064,0.95857,0.96594,0.97275,0.97899,0.98461,0.98930,0.99303,0.99583,0.99773,0.99876,0.99896,0.99835,0.99697,0.99485,0.99202,0.98851,0.98436,0.97959,0.97423,0.96833,0.96190,0.95498,0.94761,0.93981,0.93161,0.92305,0.91416,0.90496,0.89550,0.88580,0.87590,0.86581,0.85559,0.84525,0.83484,0.82437,0.81389,0.80342,0.79299,0.78264,0.77240,0.76230,0.75237,0.74265,0.73316,0.72393,0.71500,0.70599,0.69651,0.68660,0.67627,0.66556,0.65448,0.64308,0.63137,0.61938,0.60713,0.59466,0.58199,0.56914,0.55614,0.54303,0.52981,0.51653,0.50321,0.48987,0.47654,0.46325,0.45002,0.43688,0.42386,0.41098,0.39826,0.38575,0.37345,0.36140,0.34963,0.33816,0.32701,0.31622,0.30581,0.29581,0.28623,0.27712,0.26849,0.26038,0.25280,0.24579,0.23937,0.23356,0.22835,0.22370,0.21960,0.21602,0.21294,0.21032,0.20815,0.20640,0.20504,0.20406,0.20343,0.20311,0.20310,0.20336,0.20386,0.20459,0.20552,0.20663,0.20788,0.20926,0.21074,0.21230,0.21391,0.21555,0.21719,0.21880,0.22038,0.22188,0.22328,0.22456,0.22570,0.22667,0.22744,0.22800,0.22831,0.22836,0.22811,0.22754,0.22663,0.22536,0.22369,0.22161,0.21918,0.21650,0.21358,0.21043,0.20706,0.20348,0.19971,0.19577,0.19165,0.18738,0.18297,0.17842,0.17376,0.16899,0.16412,0.15918,0.15417,0.14910,0.14398,0.13883,0.13367,0.12849,0.12332,0.11817,0.11305,0.10797,0.10294,0.09798,0.09310,0.08831,0.08362,0.07905,0.07461,0.07031,0.06616,0.06218,0.05837,0.05475,0.05134,0.04814,0.04516,0.04243,0.03993,0.03753,0.03521,0.03297,0.03082,0.02875,0.02677,0.02487,0.02305,0.02131,0.01966,0.01809,0.01660,0.01520,0.01387,0.01264,0.01148,0.01041,0.00942,0.00851,0.00769,0.00695,0.00629,0.00571,0.00522,0.00481,0.00449,0.00424,0.00408,0.00401,0.00401,0.00410,0.00427,0.00453,0.00486,0.00529,0.00579,0.00638,0.00705,0.00780,0.00863,0.00955,0.01055};
diff --git a/teensy_cvgate_mcp4725_neopixel/teensy_cvgate_mcp4725_neopixel.ino b/teensy_cvgate_mcp4725_neopixel/teensy_cvgate_mcp4725_neopixel.ino
@@ -0,0 +1,202 @@
+/*
+* EEGSynth Teensy based CV/Gate controller. This sketch allows
+* one to use control voltages and gates to interface a computer
+* with an analog synthesizer. The hardware comprises a Teensy 
+* with two MCP4725 12-bit DAC breakout boards.
+*
+* Some example sequences of characters are
+*   *c1v1024#  control 1 voltage 5*1024/4095 = 1.25 V
+*   *g1v1#     gate 1 value ON
+*
+* This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
+* See http://creativecommons.org/licenses/by-sa/4.0/
+*
+* Copyright (C) 2020, Robert Oostenveld, http://www.eegsynth.org/
+*/
+
+#include <Wire.h>//Include the Wire library to talk I2C
+#include <Adafruit_NeoPixel.h>
+
+#include "colormap.h"
+
+#define enable1 true
+#define enable2 true
+
+// 0x60 is the I2C Address of the MCP4725, by default (A0 pulled to GND).
+// Please note that this breakout is for the MCP4725A0.
+// For devices with A0 pulled HIGH, use 0x61
+#define address1 0x60
+#define address2 0x61
+
+#define gate1pin A0      // the pin controlling the digital gate
+#define gate2pin A1      // the pin controlling the digital gate
+
+#define MCP4726_CMD_WRITEDAC            (0x40)  // Writes data to the DAC
+#define MCP4726_CMD_WRITEDACEEPROM      (0x60)  // Writes data to the DAC and the EEPROM (persisting the assigned value after reset)
+
+// the values of the DAC range from 0 to 4095 (12 bits)
+#define MAXVALUE  4095.
+
+// these are the commands over the serial interface
+#define NONE      0
+#define VOLTAGE   1
+#define GATE      2
+
+// status after parsing the commands
+#define OK     0
+#define ERROR -1
+
+#define PIXELPIN 20
+#define NUMPIXELS 4
+#define BRIGHTNESS 0.3
+
+Adafruit_NeoPixel pixels(NUMPIXELS, PIXELPIN, NEO_GRB + NEO_KHZ800);
+
+// the initial values of the output control voltages and gates
+int voltage1 = 0, voltage2 = 0;
+int gate1 = 0, gate2 = 0;
+
+void setColor(int led, float value) {
+  byte r, g, b;
+  int index = value*255.;
+  index = (index > 255 ? 255 : index);  // must be between 0 and 255
+  r = 255*R[index]*BRIGHTNESS;
+  g = 255*G[index]*BRIGHTNESS;
+  b = 255*B[index]*BRIGHTNESS;
+  pixels.setPixelColor(led, pixels.Color(r, g, b));
+  pixels.show();
+  return;
+}
+
+void setValue(uint16_t address, uint16_t value) {
+  uint8_t msb, lsb;
+  msb = (value / 16);
+  lsb = (value % 16) << 4;
+  Wire.beginTransmission(address);
+  Wire.write(MCP4726_CMD_WRITEDAC);   // cmd to update the DAC
+  Wire.write(msb);                    // the 8 most significant bits...
+  Wire.write(lsb);                    // the 4 least significant bits...
+  Wire.endTransmission();
+  return;
+}
+
+void setup() {
+  // initialize the serial communication:
+  while (!Serial) {;}
+  Serial.begin(115200);
+  Serial.print("\n[teensy_cvgate_mcp4725_neopixel/ ");
+  Serial.print(__DATE__);
+  Serial.print(" / ");
+  Serial.print(__TIME__);
+  Serial.println("]");
+  Serial.setTimeout(1000);
+
+  Wire.begin();
+
+  // initialize the gate pins as output:
+  pinMode(gate1pin, OUTPUT);
+  pinMode(gate2pin, OUTPUT);
+
+  // INITIALIZE NeoPixel strip object
+  pixels.begin(); 
+
+  // Set all pixel colors to 'off'
+  pixels.clear(); 
+
+  return;
+}
+
+void loop() {
+  byte b, channel = 0, command = NONE, status = OK;
+  int value = 0;
+
+  if (Serial.available()) {
+
+    // parse the input over the serial connection
+    b = Serial.read();
+    if (b == '*') {
+      Serial.readBytes(&b, 1);
+      if (b == 'c') {
+        command = VOLTAGE;
+        value = 0;
+        Serial.readBytes(&b, 1); channel = b - 48; // character '1' is ascii value 49
+        Serial.readBytes(&b, 1); // 'v'
+        Serial.readBytes(&b, 1); value  = (b - 48) * 1000;
+        Serial.readBytes(&b, 1); value += (b - 48) * 100;
+        Serial.readBytes(&b, 1); value += (b - 48) * 10;
+        Serial.readBytes(&b, 1); value += (b - 48) * 1;
+        Serial.readBytes(&b, 1); command = (b == '#' ? command : NONE);
+      }
+      else if (b == 'g') {
+        command = GATE;
+        Serial.readBytes(&b, 1); channel = b - 48; // character '1' is ascii value 49
+        Serial.readBytes(&b, 1); // 'v'
+        Serial.readBytes(&b, 1); value  = (b == '1');
+        Serial.readBytes(&b, 1); command = (b == '#' ? command : NONE);
+      }
+      else {
+        command = NONE;
+      }
+    }
+    else {
+      command = NONE;
+    }
+
+    // update the internal state of all output channels
+    if (command == VOLTAGE) {
+      switch (channel) {
+        case 1:
+          voltage1 = (value > MAXVALUE ? MAXVALUE : value);
+          status = (enable1 ? OK : ERROR);
+          break;
+        case 2:
+          voltage2 = (value > MAXVALUE ? MAXVALUE : value);
+          status = (enable2 ? OK : ERROR);
+          break;
+        default:
+          status = ERROR;
+      }
+
+    }
+    else if (command == GATE) {
+      switch (channel) {
+        case 1:
+          gate1 = (value != 0);
+          status = OK;
+          break;
+        case 2:
+          gate2 = (value != 0);
+          status = OK;
+          break;
+        default:
+          status = ERROR;
+      }
+    }
+    else {
+      status = ERROR;
+    }
+    if (status == OK)
+      Serial.println("ok");
+    else if (status == ERROR)
+      Serial.println("error");
+  }
+  else {
+    // refresh the output voltages and gates
+    if (enable1) {
+      setValue(address1, voltage1);
+      digitalWrite(gate1pin, gate1);
+    }
+    if (enable2) {
+      setValue(address2, voltage2);
+      digitalWrite(gate2pin, gate2);
+    }
+
+    // update the color of the Neopixels
+    // the integer representation of the control voltage is represented between 0 and 4095
+    setColor(0, voltage1/MAXVALUE);
+    setColor(1, voltage2/MAXVALUE); 
+    // the integer representation of the gate voltage is either 0 or 1
+    setColor(2, gate1); 
+    setColor(3, gate2); 
+  }
+} //main