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/*
* RtdSensor31865.cpp
*
* Created on: 8 Jun 2017
* Author: David
*/
#include "RtdSensor31865.h"
#include "RepRap.h"
#include "Platform.h"
#include "GCodes/GCodeBuffer/GCodeBuffer.h"
const uint32_t MAX31865_Frequency = 4000000; // maximum for MAX31865 is also 5MHz
// SPI modes:
// If the inactive state of SCL is LOW (CPOL = 0) (in the case of the MAX31865, this is sampled on the falling edge of CS):
// The MAX31865 changes data after the rising edge of CLK, and samples input data on the falling edge.
// This requires NCPHA = 0.
const uint8_t MAX31865_SpiMode = SPI_MODE_1;
// Define the minimum interval between readings. The MAX31865 needs 62.5ms in 50Hz filter mode.
const uint32_t MinimumReadInterval = 100; // minimum interval between reads, in milliseconds
// Default configuration register
// Note that to get the MAX31865 to do continuous conversions, we need to set the bias bit as well as the continuous-conversion bit
// Vbias=1
// Conversion mode=1
// 1shot = 0
// 3wire=0
// Fault detection=00 no action
// Fault status=1 clear any existing fault
// 50/60Hz reject=1 for 50Hz (0 for 60Hz)
const uint8_t DefaultCr0 = 0b11000011;
const uint8_t Cr0ReadMask = 0b11011101; // bits 1 and 5 auto clear, so ignore the value read
const uint16_t DefaultRef = 400;
RtdSensor31865::RtdSensor31865(unsigned int sensorNum) noexcept
: SpiTemperatureSensor(sensorNum, "PT100 (MAX31865)", MAX31865_SpiMode, MAX31865_Frequency),
rref(DefaultRef), cr0(DefaultCr0)
{
}
// Configure this temperature sensor
GCodeResult RtdSensor31865::Configure(GCodeBuffer& gb, const StringRef& reply)
{
bool seen = false;
if (!ConfigurePort(gb, reply, seen))
{
return GCodeResult::error;
}
TryConfigureSensorName(gb, seen);
if (gb.Seen('F'))
{
seen = true;
if (gb.GetIValue() == 60)
{
cr0 &= ~0x01; // set 60Hz rejection
}
else
{
cr0 |= 0x01; // default to 50Hz rejection
}
}
if (gb.Seen('W'))
{
seen = true;
if (gb.GetUIValue() == 3)
{
cr0 |= 0x10; // 3 wire configuration
}
else
{
cr0 &= ~0x10; // 2 or 4 wire configuration
}
}
if (gb.Seen('R'))
{
seen = true;
rref = (uint16_t)gb.GetUIValue();
}
if (seen)
{
// Initialise the sensor
InitSpi();
TemperatureError rslt;
for (unsigned int i = 0; i < 3; ++i) // try 3 times
{
rslt = TryInitRtd();
if (rslt == TemperatureError::success)
{
break;
}
delay(MinimumReadInterval);
}
lastReadingTime = millis();
lastResult = rslt;
lastTemperature = 0.0;
if (rslt != TemperatureError::success)
{
reprap.GetPlatform().MessageF(ErrorMessage, "Failed to initialise RTD: %s\n", TemperatureErrorString(rslt));
}
}
else
{
CopyBasicDetails(reply);
reply.catf(", %s wires, reject %dHz, reference resistor %u ohms", (cr0 & 0x10) ? "3" : "2/4", (cr0 & 0x01) ? 50 : 60, (unsigned int)rref);
}
return GCodeResult::ok;
}
// Try to initialise the RTD
TemperatureError RtdSensor31865::TryInitRtd() const noexcept
{
const uint8_t modeData[2] = { 0x80, cr0 }; // write register 0
uint32_t rawVal;
TemperatureError sts = DoSpiTransaction(modeData, ARRAY_SIZE(modeData), rawVal);
if (sts == TemperatureError::success)
{
delayMicroseconds(1);
static const uint8_t readData[2] = { 0x00, 0x00 }; // read register 0
sts = DoSpiTransaction(readData, ARRAY_SIZE(readData), rawVal);
}
//debugPrintf("Status %d data %04x\n", (int)sts, (uint16_t)rawVal);
if (sts == TemperatureError::success && (rawVal & Cr0ReadMask) != (cr0 & Cr0ReadMask))
{
sts = TemperatureError::badResponse;
}
return sts;
}
void RtdSensor31865::Poll() noexcept
{
static const uint8_t dataOut[4] = {0, 0x55, 0x55, 0x55}; // read registers 0 (control), 1 (MSB) and 2 (LSB)
uint32_t rawVal;
TemperatureError sts = DoSpiTransaction(dataOut, ARRAY_SIZE(dataOut), rawVal);
if (sts != TemperatureError::success)
{
SetResult(sts);
}
else
{
if ( (((rawVal >> 16) & Cr0ReadMask) != (cr0 & Cr0ReadMask)) // if control register not as expected
|| (rawVal & 1) != 0 // or fault bit set
)
{
static const uint8_t faultDataOut[2] = {0x07, 0x55};
if (DoSpiTransaction(faultDataOut, ARRAY_SIZE(faultDataOut), rawVal)== TemperatureError::success) // read the fault register
{
sts = (rawVal & 0x04) ? TemperatureError::overOrUnderVoltage
: (rawVal & 0x18) ? TemperatureError::openCircuit
: TemperatureError::hardwareError;
}
else
{
sts = TemperatureError::hardwareError;
}
SetResult(sts);
delayMicroseconds(1); // MAX31865 requires CS to be high for 400ns minimum
TryInitRtd(); // clear the fault and hope for better luck next time
}
else
{
const uint16_t ohmsx100 = (uint16_t)((((rawVal >> 1) & 0x7FFF) * rref * 100) >> 15);
float t;
sts = GetPT100Temperature(t, ohmsx100);
SetResult(t, sts);
}
}
}
// End
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