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104 lines
2.9 KiB
104 lines
2.9 KiB
/**
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* Marlin 3D Printer Firmware
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* Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
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*
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* Based on Sprinter and grbl.
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* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*
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*/
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/**
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* adc_mcp3426.cpp - library for MicroChip MCP3426 I2C A/D converter
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*
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* For implementation details, please take a look at the datasheet:
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* https://www.microchip.com/en-us/product/MCP3426
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*/
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#include "../../inc/MarlinConfig.h"
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#if ENABLED(HAS_MCP3426_ADC)
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#include "adc_mcp3426.h"
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// Read the ADC value from MCP342X on a specific channel
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int16_t MCP3426::ReadValue(uint8_t channel, uint8_t gain) {
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Error = false;
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#if PINS_EXIST(I2C_SCL, I2C_SDA) && DISABLED(SOFT_I2C_EEPROM)
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Wire.setSDA(pin_t(I2C_SDA_PIN));
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Wire.setSCL(pin_t(I2C_SCL_PIN));
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#endif
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Wire.begin(); // No address joins the BUS as the master
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Wire.beginTransmission(I2C_ADDRESS(MCP342X_ADC_I2C_ADDRESS));
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// Continuous Conversion Mode, 16 bit, Channel 1, Gain x4
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// 26 = 0b00011000
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// RXXCSSGG
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// R = Ready Bit
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// XX = Channel (00=1, 01=2, 10=3 (MCP3428), 11=4 (MCP3428))
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// C = Conversion Mode Bit (1= Continuous Conversion Mode (Default))
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// SS = Sample rate, 10=15 samples per second @ 16 bits
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// GG = Gain 00 =x1
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uint8_t controlRegister = 0b00011000;
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if (channel == 2) controlRegister |= 0b00100000; // Select channel 2
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if (gain == 2)
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controlRegister |= 0b00000001;
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else if (gain == 4)
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controlRegister |= 0b00000010;
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else if (gain == 8)
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controlRegister |= 0b00000011;
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Wire.write(controlRegister);
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if (Wire.endTransmission() != 0) {
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Error = true;
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return 0;
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}
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const uint8_t len = 3;
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uint8_t buffer[len] = {};
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do {
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Wire.requestFrom(I2C_ADDRESS(MCP342X_ADC_I2C_ADDRESS), len);
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if (Wire.available() != len) {
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Error = true;
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return 0;
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}
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for (uint8_t i = 0; i < len; ++i)
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buffer[i] = Wire.read();
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// Is conversion ready, if not loop around again
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} while ((buffer[2] & 0x80) != 0);
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union TwoBytesToInt16 {
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uint8_t bytes[2];
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int16_t integervalue;
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};
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TwoBytesToInt16 ConversionUnion;
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ConversionUnion.bytes[1] = buffer[0];
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ConversionUnion.bytes[0] = buffer[1];
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return ConversionUnion.integervalue;
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}
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MCP3426 mcp3426;
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#endif // HAS_MCP3426_ADC
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