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The PrintrBoard Rev F utilizes a mcp4728 DAC to set motor current. Printrbot's implementation utilizes 2 new M-codes to set and write the DAC settings to the DAC EEPROM: `M909` (Read DAC) and `M910` (Write DAC). `M907` is re-used to set value, `M908` for direct control. The Pins file for the RevF board is included.
116 lines
3.2 KiB
C++
116 lines
3.2 KiB
C++
/*
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mcp4728.cpp - Arduino library for MicroChip MCP4728 I2C D/A converter
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For implementation details, please take a look at the datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/22187a.pdf
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For discussion and feedback, please go to http://arduino.cc/forum/index.php/topic,51842.0.html
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*/
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/* _____PROJECT INCLUDES_____________________________________________________ */
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#include "dac_mcp4728.h"
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#if ENABLED(DAC_STEPPER_CURRENT)
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// Used Global variables
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uint16_t mcp4728_values[4];
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/*
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Begin I2C, get current values (input register and eeprom) of mcp4728
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*/
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void mcp4728_init() {
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Wire.begin();
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Wire.requestFrom(int(DAC_DEV_ADDRESS), 24);
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while(Wire.available()) {
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int deviceID = Wire.receive();
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int hiByte = Wire.receive();
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int loByte = Wire.receive();
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int isEEPROM = (deviceID & 0B00001000) >> 3;
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int channel = (deviceID & 0B00110000) >> 4;
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if (isEEPROM != 1) {
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mcp4728_values[channel] = word((hiByte & 0B00001111), loByte);
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}
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}
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}
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/*
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Write input resister value to specified channel using fastwrite method.
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Channel : 0-3, Values : 0-4095
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*/
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uint8_t mcp4728_analogWrite(uint8_t channel, uint16_t value) {
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mcp4728_values[channel] = value;
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return mcp4728_fastWrite();
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}
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/*
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Write all input resistor values to EEPROM using SequencialWrite method.
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This will update both input register and EEPROM value
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This will also write current Vref, PowerDown, Gain settings to EEPROM
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*/
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uint8_t mcp4728_eepromWrite() {
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Wire.beginTransmission(DAC_DEV_ADDRESS);
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Wire.send(SEQWRITE);
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for (uint8_t channel=0; channel <= 3; channel++) {
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Wire.send(DAC_STEPPER_VREF << 7 | 0 << 5 | DAC_STEPPER_GAIN << 4 | highByte(mcp4728_values[channel]));
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Wire.send(lowByte(mcp4728_values[channel]));
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}
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return Wire.endTransmission();
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}
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/*
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Write Voltage reference setting to all input regiters
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*/
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uint8_t mcp4728_setVref_all(uint8_t value) {
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Wire.beginTransmission(DAC_DEV_ADDRESS);
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Wire.send(VREFWRITE | value << 3 | value << 2 | value << 1 | value);
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return Wire.endTransmission();
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}
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/*
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Write Gain setting to all input regiters
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*/
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uint8_t mcp4728_setGain_all(uint8_t value) {
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Wire.beginTransmission(DAC_DEV_ADDRESS);
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Wire.send(GAINWRITE | value << 3 | value << 2 | value << 1 | value);
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return Wire.endTransmission();
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}
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/*
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Return Input Regiter value
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*/
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uint16_t mcp4728_getValue(uint8_t channel) { return mcp4728_values[channel]; }
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/*
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// Steph: Might be useful in the future
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// Return Vout
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uint16_t mcp4728_getVout(uint8_t channel) {
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uint32_t vref = 2048;
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uint32_t vOut = (vref * mcp4728_values[channel] * (_DAC_STEPPER_GAIN + 1)) / 4096;
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if (vOut > defaultVDD) vOut = defaultVDD;
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return vOut;
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}
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*/
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/*
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FastWrite input register values - All DAC ouput update. refer to DATASHEET 5.6.1
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DAC Input and PowerDown bits update.
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No EEPROM update
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*/
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uint8_t mcp4728_fastWrite() {
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Wire.beginTransmission(DAC_DEV_ADDRESS);
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for (uint8_t channel=0; channel <= 3; channel++) {
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Wire.send(highByte(mcp4728_values[channel]));
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Wire.send(lowByte(mcp4728_values[channel]));
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}
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return Wire.endTransmission();
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}
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/*
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Common function for simple general commands
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*/
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uint8_t mcp4728_simpleCommand(byte simpleCommand) {
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Wire.beginTransmission(GENERALCALL);
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Wire.send(simpleCommand);
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return Wire.endTransmission();
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}
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#endif // DAC_STEPPER_CURRENT
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