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- /**
- * Marlin 3D Printer Firmware
- * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
- *
- * Based on Sprinter and grbl.
- * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <https://www.gnu.org/licenses/>.
- *
- */
-
- /**
- * Based on Based on Adafruit MAX31865 library:
- *
- * This is a library for the Adafruit PT100/P1000 RTD Sensor w/MAX31865
- * Designed specifically to work with the Adafruit RTD Sensor
- * https://www.adafruit.com/products/3328
- *
- * This sensor uses SPI to communicate, 4 pins are required to interface.
- *
- * Adafruit invests time and resources providing this open source code,
- * please support Adafruit and open-source hardware by purchasing
- * products from Adafruit!
- *
- * Written by Limor Fried/Ladyada for Adafruit Industries.
- *
- * Modifications by JoAnn Manges (@GadgetAngel)
- * Copyright (c) 2020, JoAnn Manges
- * All rights reserved.
- */
-
- #include "../inc/MarlinConfig.h"
-
- #if HAS_MAX31865 && !USE_ADAFRUIT_MAX31865
-
- #include "MAX31865.h"
-
- #ifndef MAX31865_MIN_SAMPLING_TIME_MSEC
- #define MAX31865_MIN_SAMPLING_TIME_MSEC 0
- #endif
-
- #define DEBUG_OUT ENABLED(DEBUG_MAX31865)
- #include "../core/debug_out.h"
-
- // The maximum speed the MAX31865 can do is 5 MHz
- SPISettings MAX31865::spiConfig = SPISettings(
- TERN(TARGET_LPC1768, SPI_QUARTER_SPEED, TERN(ARDUINO_ARCH_STM32, SPI_CLOCK_DIV4, 500000)),
- MSBFIRST,
- SPI_MODE1 // CPOL0 CPHA1
- );
-
- #if DISABLED(LARGE_PINMAP)
-
- /**
- * Create the interface object using software (bitbang) SPI for PIN values
- * less than or equal to 127.
- *
- * @param spi_cs the SPI CS pin to use
- * @param spi_mosi the SPI MOSI pin to use
- * @param spi_miso the SPI MISO pin to use
- * @param spi_clk the SPI clock pin to use
- */
- MAX31865::MAX31865(int8_t spi_cs, int8_t spi_mosi, int8_t spi_miso, int8_t spi_clk) {
- cselPin = spi_cs;
- mosiPin = spi_mosi;
- misoPin = spi_miso;
- sclkPin = spi_clk;
- }
-
- /**
- * Create the interface object using hardware SPI for PIN for PIN values less
- * than or equal to 127.
- *
- * @param spi_cs the SPI CS pin to use along with the default SPI device
- */
- MAX31865::MAX31865(int8_t spi_cs) {
- cselPin = spi_cs;
- sclkPin = misoPin = mosiPin = -1;
- }
-
- #else // LARGE_PINMAP
-
- /**
- * Create the interface object using software (bitbang) SPI for PIN values
- * which are larger than 127. If you have PIN values less than or equal to
- * 127 use the other call for SW SPI.
- *
- * @param spi_cs the SPI CS pin to use
- * @param spi_mosi the SPI MOSI pin to use
- * @param spi_miso the SPI MISO pin to use
- * @param spi_clk the SPI clock pin to use
- * @param pin_mapping set to 1 for positive pin values
- */
- MAX31865::MAX31865(uint32_t spi_cs, uint32_t spi_mosi, uint32_t spi_miso, uint32_t spi_clk, uint8_t pin_mapping) {
- cselPin = spi_cs;
- mosiPin = spi_mosi;
- misoPin = spi_miso;
- sclkPin = spi_clk;
- }
-
- /**
- * Create the interface object using hardware SPI for PIN values which are
- * larger than 127. If you have PIN values less than or equal to 127 use
- * the other call for HW SPI.
- *
- * @param spi_cs the SPI CS pin to use along with the default SPI device
- * @param pin_mapping set to 1 for positive pin values
- */
- MAX31865::MAX31865(uint32_t spi_cs, uint8_t pin_mapping) {
- cselPin = spi_cs;
- sclkPin = misoPin = mosiPin = -1UL; //-1UL or 0xFFFFFFFF or 4294967295
- }
-
- #endif // LARGE_PINMAP
-
- /**
- *
- * Instance & Class methods
- *
- */
-
- /**
- * Initialize the SPI interface and set the number of RTD wires used
- *
- * @param wires The number of wires as an enum: MAX31865_2WIRE, MAX31865_3WIRE, or MAX31865_4WIRE.
- * @param zero_res The resistance of the RTD at 0°C, in ohms.
- * @param ref_res The resistance of the reference resistor, in ohms.
- * @param wire_res The resistance of the wire connecting the sensor to the RTD, in ohms.
- */
- void MAX31865::begin(max31865_numwires_t wires, const_float_t zero_res, const_float_t ref_res, const_float_t wire_res) {
- resNormalizer = 100.0f / zero_res; // reciprocal of resistance, scaled by 100
- refRes = ref_res;
- wireRes = wire_res;
-
- pinMode(cselPin, OUTPUT);
- digitalWrite(cselPin, HIGH);
-
- if (sclkPin != TERN(LARGE_PINMAP, -1UL, 255))
- softSpiInit(); // Define pin modes for Software SPI
- else {
- DEBUG_ECHOLNPGM("Init MAX31865 Hardware SPI");
- SPI.begin(); // Start and configure hardware SPI
- }
-
- initFixedFlags(wires);
-
- DEBUG_ECHOLNPGM("MAX31865 Regs: CFG ", readRegister8(MAX31865_CONFIG_REG),
- "|RTD ", readRegister16(MAX31865_RTDMSB_REG),
- "|HTHRS ", readRegister16(MAX31865_HFAULTMSB_REG),
- "|LTHRS ", readRegister16(MAX31865_LFAULTMSB_REG),
- "|FLT ", readRegister8(MAX31865_FAULTSTAT_REG));
-
- // fault detection cycle seems to initialize the sensor better
- runAutoFaultDetectionCycle(); // also initializes flags
-
- if (lastFault)
- SERIAL_ECHOLNPGM("MAX31865 init fault ", lastFault);
-
- writeRegister16(MAX31865_HFAULTMSB_REG, 0xFFFF);
- writeRegister16(MAX31865_LFAULTMSB_REG, 0);
-
- #if ENABLED(MAX31865_USE_AUTO_MODE) // make a proper first read to initialize _lastRead
-
- uint16_t rtd = readRegister16(MAX31865_RTDMSB_REG);
-
- #if MAX31865_IGNORE_INITIAL_FAULTY_READS > 0
- rtd = fixFault(rtd);
- #endif
-
- if (rtd & 1) {
- lastRead = 0xFFFF; // some invalid value
- lastFault = readRegister8(MAX31865_FAULTSTAT_REG);
- clearFault(); // also clears the bias voltage flag, so no further action is required
-
- DEBUG_ECHOLNPGM("MAX31865 read fault: ", rtd);
- }
- else {
- DEBUG_ECHOLNPGM("RTD MSB:", (rtd >> 8), " RTD LSB:", (rtd & 0x00FF));
- lastRead = rtd;
- TERN_(MAX31865_USE_READ_ERROR_DETECTION, lastReadStamp = millis());
- }
-
- #else
-
- enableBias();
- DELAY_US(2000); // according to the datasheet, 10.5τ+1msec (see below)
- oneShot();
- DELAY_US(63000);
- uint16_t rtd = readRegister16(MAX31865_RTDMSB_REG);
-
- #if MAX31865_IGNORE_INITIAL_FAULTY_READS > 0
- rtd = fixFault(rtd);
- #endif
-
- if (rtd & 1) {
- lastRead = 0xFFFF; // some invalid value
- lastFault = readRegister8(MAX31865_FAULTSTAT_REG);
- clearFault(); // also clears the bias voltage flag, so no further action is required
-
- DEBUG_ECHOLNPGM("MAX31865 read fault: ", rtd);
- }
- else {
- DEBUG_ECHOLNPGM("RTD MSB:", (rtd >> 8), " RTD LSB:", (rtd & 0x00FF));
-
- resetFlags();
-
- lastRead = rtd;
- nextEvent = SETUP_BIAS_VOLTAGE;
- millis_t now = millis();
- nextEventStamp = now + MAX31865_MIN_SAMPLING_TIME_MSEC;
-
- TERN_(MAX31865_USE_READ_ERROR_DETECTION, lastReadStamp = now);
- }
-
- #endif // MAX31865_USE_AUTO_MODE
-
- DEBUG_ECHOLNPGM(
- TERN(LARGE_PINMAP, "LARGE_PINMAP", "Regular")
- " begin call with cselPin: ", cselPin,
- " misoPin: ", misoPin,
- " sclkPin: ", sclkPin,
- " mosiPin: ", mosiPin,
- " config: ", readRegister8(MAX31865_CONFIG_REG)
- );
- }
-
- /**
- * Return and clear the last fault value
- *
- * @return The raw unsigned 8-bit FAULT status register or spike fault
- */
- uint8_t MAX31865::readFault() {
- uint8_t r = lastFault;
- lastFault = 0;
- return r;
- }
-
- /**
- * Clear last fault
- */
- void MAX31865::clearFault() {
- setConfig(MAX31865_CONFIG_FAULTSTAT, 1);
- }
-
- /**
- * Reset flags
- */
- void MAX31865::resetFlags() {
- writeRegister8(MAX31865_CONFIG_REG, stdFlags);
- }
-
- /**
- * Enable the bias voltage on the RTD sensor
- */
- void MAX31865::enableBias() {
- setConfig(MAX31865_CONFIG_BIAS, 1);
- }
-
- /**
- * Start a one-shot temperature reading.
- */
- void MAX31865::oneShot() {
- setConfig(MAX31865_CONFIG_1SHOT | MAX31865_CONFIG_BIAS, 1);
- }
-
- void MAX31865::runAutoFaultDetectionCycle() {
- writeRegister8(MAX31865_CONFIG_REG, (stdFlags & 0x11) | 0x84 ); // cfg reg = 100X010Xb
- DELAY_US(600);
- for (int i = 0; i < 10 && (readRegister8(MAX31865_CONFIG_REG) & 0xC) > 0; i++) DELAY_US(100); // Fault det completes when bits 2 and 3 are zero (or after 10 tries)
- readFault();
- clearFault();
- }
-
- /**
- * Set a value in the configuration register.
- *
- * @param config 8-bit value for the config item
- * @param enable whether to enable or disable the value
- */
- void MAX31865::setConfig(uint8_t config, bool enable) {
- uint8_t t = stdFlags;
- if (enable)
- t |= config;
- else
- t &= ~config;
- writeRegister8(MAX31865_CONFIG_REG, t);
- }
-
- /**
- * Initialize standard flags with flags that will not change during operation (Hz, polling mode and no. of wires)
- *
- * @param wires The number of wires in enum format
- */
- void MAX31865::initFixedFlags(max31865_numwires_t wires) {
-
- // set config-defined flags (same for all sensors)
- stdFlags = TERN(MAX31865_50HZ_FILTER, MAX31865_CONFIG_FILT50HZ, MAX31865_CONFIG_FILT60HZ) |
- TERN(MAX31865_USE_AUTO_MODE, MAX31865_CONFIG_MODEAUTO | MAX31865_CONFIG_BIAS, MAX31865_CONFIG_MODEOFF);
-
- if (wires == MAX31865_3WIRE)
- stdFlags |= MAX31865_CONFIG_3WIRE; // 3 wire
- else
- stdFlags &= ~MAX31865_CONFIG_3WIRE; // 2 or 4 wire
- }
-
- #if MAX31865_IGNORE_INITIAL_FAULTY_READS > 0
-
- inline uint16_t MAX31865::fixFault(uint16_t rtd) {
- if (!ignore_faults || !(rtd & 1))
- return rtd;
-
- ignore_faults--;
- clearFault();
-
- DEBUG_ECHOLNPGM("MAX31865 ignoring fault ", (MAX31865_IGNORE_INITIAL_FAULTY_READS) - ignore_faults);
-
- return rtd & ~1; // 0xFFFE
- }
-
- #endif
-
- inline uint16_t MAX31865::readRawImmediate() {
- uint16_t rtd = readRegister16(MAX31865_RTDMSB_REG);
- DEBUG_ECHOLNPGM("MAX31865 RTD MSB:", (rtd >> 8), " LSB:", (rtd & 0x00FF));
-
- #if MAX31865_IGNORE_INITIAL_FAULTY_READS > 0
- rtd = fixFault(rtd);
- #endif
-
- if (rtd & 1) {
- lastFault = readRegister8(MAX31865_FAULTSTAT_REG);
- lastRead |= 1;
- clearFault(); // also clears the bias voltage flag, so no further action is required
- DEBUG_ECHOLNPGM("MAX31865 read fault: ", lastFault);
- }
- else {
- TERN_(MAX31865_USE_READ_ERROR_DETECTION, const millis_t ms = millis());
- if (TERN0(MAX31865_USE_READ_ERROR_DETECTION, ABS((int)(lastRead - rtd)) > 500 && PENDING(ms, lastReadStamp + 1000))) {
- // If 2 readings within 1s differ too much (~20°C) it's a read error.
- lastFault = 0x01;
- lastRead |= 1;
- DEBUG_ECHOLNPGM("MAX31865 read error: ", rtd);
- }
- else {
- lastRead = rtd;
- TERN_(MAX31865_USE_READ_ERROR_DETECTION, lastReadStamp = ms);
- }
- }
-
- return rtd;
- }
-
- /**
- * Read the raw 16-bit value from the RTD_REG in one shot mode. This will include
- * the fault bit, D0.
- *
- * @return The raw unsigned 16-bit register value with ERROR bit attached, NOT temperature!
- */
- uint16_t MAX31865::readRaw() {
-
- #if ENABLED(MAX31865_USE_AUTO_MODE)
-
- readRawImmediate();
-
- #else
-
- const millis_t ms = millis();
-
- if (PENDING(ms, nextEventStamp)) {
- DEBUG_ECHOLNPGM("MAX31865 waiting for event ", nextEvent);
- return lastRead;
- }
-
- switch (nextEvent) {
- case SETUP_BIAS_VOLTAGE:
- enableBias();
- nextEventStamp = ms + 2; // wait at least 10.5*τ (τ = 100nF*430Ω max for PT100 / 10nF*4.3ΚΩ for PT1000 = 43μsec) + 1msec
- nextEvent = SETUP_1_SHOT_MODE;
- DEBUG_ECHOLNPGM("MAX31865 bias voltage enabled");
- break;
-
- case SETUP_1_SHOT_MODE:
- oneShot();
- nextEventStamp = ms + TERN(MAX31865_50HZ_FILTER, 63, 52); // wait at least 52msec for 60Hz (63msec for 50Hz) before reading RTD register
- nextEvent = READ_RTD_REG;
- DEBUG_ECHOLNPGM("MAX31865 1 shot mode enabled");
- break;
-
- case READ_RTD_REG:
-
- if (!(readRawImmediate() & 1)) // if clearFault() was not invoked, need to clear the bias voltage and 1-shot flags
- resetFlags();
-
- nextEvent = SETUP_BIAS_VOLTAGE;
- nextEventStamp = ms + (MAX31865_MIN_SAMPLING_TIME_MSEC); // next step should not occur within less than MAX31865_MIN_SAMPLING_TIME_MSEC from the last one
- break;
- }
-
- #endif
-
- return lastRead;
- }
-
- /**
- * Calculate and return the resistance value of the connected RTD.
- *
- * @return The raw RTD resistance value, NOT temperature!
- */
- float MAX31865::readResistance() {
- // Strip the error bit (D0) and convert to a float ratio.
- // less precise method: (readRaw() * refRes) >> 16
- return ((readRaw() * RECIPROCAL(65536.0f)) * refRes - wireRes);
- }
-
- /**
- * Read the RTD and pass it to temperature(float) for calculation.
- *
- * @return Temperature in C
- */
- float MAX31865::temperature() {
- return temperature(readResistance());
- }
-
- /**
- * Given the 15-bit ADC value, calculate the resistance and pass it to temperature(float) for calculation.
- *
- * @return Temperature in C
- */
- float MAX31865::temperature(const uint16_t adc_val) {
- return temperature(((adc_val) * RECIPROCAL(32768.0f)) * refRes - wireRes);
- }
-
- /**
- * Calculate the temperature in C from the RTD resistance.
- *
- * @param rtd_res the resistance value in ohms
- * @return the temperature in °C
- */
- float MAX31865::temperature(float rtd_res) {
-
- rtd_res *= resNormalizer; // normalize to 100 ohm
-
- // Constants for calculating temperature from the measured RTD resistance.
- // http://www.analog.com/media/en/technical-documentation/application-notes/AN709_0.pdf
- constexpr float RTD_Z1 = -0.0039083,
- RTD_Z2 = +1.758480889e-5,
- RTD_Z3 = -2.31e-8,
- RTD_Z4 = -1.155e-6;
-
- // Callender-Van Dusen equation
- float temp = (RTD_Z1 + sqrt(RTD_Z2 + (RTD_Z3 * rtd_res))) * RECIPROCAL(RTD_Z4);
-
- //
- // The previous equation is valid only for temperatures of 0°C and above.
- // The equation for RRTD(t) that defines negative temperature behavior is a
- // fourth-order polynomial (after expanding the third term) and is quite
- // impractical to solve for a single expression of temperature as a function
- // of resistance. So here we use a Linear Approximation instead.
- //
- if (temp < 0) {
- #ifndef MAX31865_APPROX
- #define MAX31865_APPROX 5
- #endif
-
- constexpr float RTD_C[] = {
- #if MAX31865_APPROX == 5
- -242.02, +2.2228, +2.5859e-3, -4.8260e-6, -2.8183e-8, +1.5243e-10
- #elif MAX31865_APPROX == 4
- -241.96, +2.2163, +2.8541e-3, -9.9121e-6, -1.7152e-8
- #elif MAX31865_APPROX == 3
- -242.09, +2.2276, +2.5178e-3, -5.8620e-6
- #else
- -242.97, +2.2838, +1.4727e-3
- #endif
- };
-
- float rpoly = rtd_res;
- temp = RTD_C[0];
- temp += rpoly * RTD_C[1];
- rpoly *= rtd_res; temp += rpoly * RTD_C[2];
- if (MAX31865_APPROX >= 3) { rpoly *= rtd_res; temp += rpoly * RTD_C[3]; }
- if (MAX31865_APPROX >= 4) { rpoly *= rtd_res; temp += rpoly * RTD_C[4]; }
- if (MAX31865_APPROX >= 5) { rpoly *= rtd_res; temp += rpoly * RTD_C[5]; }
- }
-
- return temp;
- }
-
- /**
- * MAX31865 SPI Timing constants
- * See MAX31865 datasheet (https://datasheets.maximintegrated.com/en/ds/MAX31865.pdf)
- * All timings in nsec, minimum values.
- */
-
- #define MAX31865_SPI_TIMING_TCC 400 // CS to SCLK setup
- #define MAX31865_SPI_TIMING_TDC 35 // Data to SCLK setup
- #define MAX31865_SPI_TIMING_TCL 100 // SCK half period
- #define MAX31865_SPI_TIMING_TCCH 100 // SCK to CS hold
- #define MAX31865_SPI_TIMING_TCWH 400 // CS inactive time (min)
-
- /**
- * Read a single byte from the specified register address.
- *
- * @param addr the register address
- * @return the register contents
- */
- uint8_t MAX31865::readRegister8(uint8_t addr) {
- uint8_t ret = 0;
- readRegisterN(addr, &ret, 1);
- return ret;
- }
-
- /**
- * Read two bytes: 1 from the specified register address, and 1 from the next address.
- *
- * @param addr the first register address
- * @return both register contents as a single 16-bit int
- */
- uint16_t MAX31865::readRegister16(uint8_t addr) {
- uint8_t buffer[2] = { 0 };
- readRegisterN(addr, buffer, 2);
- return uint16_t(buffer[0]) << 8 | buffer[1];
- }
-
- /**
- * Read +n+ bytes from a specified address into +buffer+. Set D7 to 0 to specify a read.
- *
- * @param addr the first register address
- * @param buffer storage for the read bytes
- * @param n the number of bytes to read
- */
- void MAX31865::readRegisterN(uint8_t addr, uint8_t buffer[], uint8_t n) {
-
- addr &= 0x7F; // make sure top bit is not set
-
- spiBeginTransaction();
- spiTransfer(addr);
-
- while (n--) {
- buffer[0] = spiTransfer(0xFF);
- buffer++;
- }
-
- spiEndTransaction();
- }
-
- void MAX31865::writeRegister16(uint8_t addr, uint16_t data) {
- spiBeginTransaction();
- spiTransfer(addr | 0x80); // make sure top bit is set
- spiTransfer(data >> 8);
- spiTransfer(data & 0xFF);
- spiEndTransaction();
- }
-
- /**
- * Write an 8-bit value to a register. Set D7 to 1 to specify a write.
- *
- * @param addr the address to write to
- * @param data the data to write
- */
- void MAX31865::writeRegister8(uint8_t addr, uint8_t data) {
- spiBeginTransaction();
- spiTransfer(addr | 0x80); // make sure top bit is set
- spiTransfer(data);
- spiEndTransaction();
- }
-
- void MAX31865::spiBeginTransaction() {
- digitalWrite(sclkPin, LOW); // ensure CPOL0
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TCWH); // ensure minimum time of CS inactivity after previous operation
- digitalWrite(cselPin, LOW);
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TCC);
-
- if (sclkPin == TERN(LARGE_PINMAP, -1UL, 255))
- SPI.beginTransaction(spiConfig);
- else
- digitalWrite(sclkPin, HIGH);
- }
-
- void MAX31865::spiEndTransaction() {
- if (sclkPin == TERN(LARGE_PINMAP, -1UL, 255))
- SPI.endTransaction();
- else
- digitalWrite(sclkPin, LOW);
-
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TCCH);
-
- digitalWrite(cselPin, HIGH);
- }
-
- /**
- * Transfer SPI data +x+ and read the response. From the datasheet...
- * Input data (SDI) is latched on the internal strobe edge and output data (SDO) is
- * shifted out on the shift edge. There is one clock for each bit transferred.
- * Address and data bits are transferred in groups of eight, MSB first.
- *
- * @param x an 8-bit chunk of data to write
- * @return the 8-bit response
- */
- uint8_t MAX31865::spiTransfer(uint8_t x) {
- if (sclkPin == TERN(LARGE_PINMAP, -1UL, 255))
- return SPI.transfer(x);
-
- uint8_t reply = 0;
- for (int i = 7; i >= 0; i--) {
- digitalWrite(mosiPin, x & _BV(i));
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TDC);
- digitalWrite(sclkPin, LOW);
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TCL - MAX31865_SPI_TIMING_TDC);
- reply <<= 1;
- if (digitalRead(misoPin)) reply |= 1;
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TDC);
- digitalWrite(sclkPin, HIGH);
- DELAY_NS_VAR(MAX31865_SPI_TIMING_TCL - MAX31865_SPI_TIMING_TDC);
- }
- return reply;
- }
-
- void MAX31865::softSpiInit() {
- DEBUG_ECHOLNPGM("Initializing MAX31865 Software SPI");
- pinMode(sclkPin, OUTPUT);
- digitalWrite(sclkPin, LOW);
- pinMode(mosiPin, OUTPUT);
- pinMode(misoPin, INPUT);
- }
-
- #endif // HAS_MAX31865 && !USE_ADAFRUIT_MAX31865
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