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/*
* LinearAdcTemperatureSensor.cpp
*
* Created on: 8 Jun 2017
* Author: David
*/
#include "CurrentLoopTemperatureSensor.h"
#include "RepRap.h"
#include "Platform.h"
#include "GCodes/GCodeBuffer.h"
const uint32_t MCP3204_Frequency = 1000000; // maximum for MCP3204 is 1MHz @ 2.7V, will be slightly higher at 3.3V
// The MCP3204 samples input data on the rising edge and changes the output data on the rising edge.
const uint8_t MCP3204_SpiMode = SPI_MODE_0;
// Define the minimum interval between readings
const uint32_t MinimumReadInterval = 100; // minimum interval between reads, in milliseconds
CurrentLoopTemperatureSensor::CurrentLoopTemperatureSensor(unsigned int channel)
: SpiTemperatureSensor(channel, "Current Loop", channel - FirstLinearAdcChannel, MCP3204_SpiMode, MCP3204_Frequency),
tempAt4mA(DefaultTempAt4mA), tempAt20mA(DefaultTempAt20mA)
{
CalcDerivedParameters();
}
// Initialise the linear ADC
void CurrentLoopTemperatureSensor::Init()
{
InitSpi();
for (unsigned int i = 0; i < 3; ++i) // try 3 times
{
TryGetLinearAdcTemperature();
if (lastResult == TemperatureError::success)
{
break;
}
delay(MinimumReadInterval);
}
lastReadingTime = millis();
if (lastResult != TemperatureError::success)
{
reprap.GetPlatform().MessageF(ErrorMessage, "Failed to initialise daughter board ADC: %s\n", TemperatureErrorString(lastResult));
}
}
// Configure this temperature sensor
GCodeResult CurrentLoopTemperatureSensor::Configure(unsigned int mCode, unsigned int heater, GCodeBuffer& gb, const StringRef& reply)
{
if (mCode == 305)
{
bool seen = false;
gb.TryGetFValue('L', tempAt4mA, seen);
gb.TryGetFValue('H', tempAt20mA, seen);
TryConfigureHeaterName(gb, seen);
if (seen)
{
CalcDerivedParameters();
}
else if (!gb.Seen('X'))
{
CopyBasicHeaterDetails(heater, reply);
reply.catf(", temperature range %.1f to %.1fC", (double)tempAt4mA, (double)tempAt20mA);
}
}
return GCodeResult::ok;
}
TemperatureError CurrentLoopTemperatureSensor::GetTemperature(float& t)
{
if (!inInterrupt() && millis() - lastReadingTime >= MinimumReadInterval)
{
TryGetLinearAdcTemperature();
}
t = lastTemperature;
return lastResult;
}
void CurrentLoopTemperatureSensor::CalcDerivedParameters()
{
minLinearAdcTemp = tempAt4mA - 0.25 * (tempAt20mA - tempAt4mA);
linearAdcDegCPerCount = (tempAt20mA - minLinearAdcTemp) / 4096.0;
}
// Try to get a temperature reading from the linear ADC by doing an SPI transaction
void CurrentLoopTemperatureSensor::TryGetLinearAdcTemperature()
{
// The MCP3204 waits for a high input input bit before it does anything. Call this clock 1.
// The next input bit it high for single-ended operation, low for differential. This is clock 2.
// The next 3 input bits are the channel selection bits. These are clocks 3..5.
// Clock 6 produces a null bit on its trailing edge, which is read by the processor on clock 7.
// Clocks 7..18 produce data bits B11..B0 on their trailing edges, which are read by the MCU on the leading edges of clocks 8-19.
// If we supply further clocks, then clocks 18..29 are the same data but LSB first, omitting bit 0.
// Clocks 30 onwards will be zeros.
// So we need to use at least 19 clocks. We round this up to 24 clocks, and we check that the extra 5 bits we receive are the 5 least significant data bits in reverse order.
static const uint8_t adcData[] = { 0xC0, 0x00, 0x00 }; // start bit, single ended, channel 0
uint32_t rawVal;
lastResult = DoSpiTransaction(adcData, 3, rawVal);
//debugPrintf("ADC data %u\n", rawVal);
if (lastResult == TemperatureError::success)
{
const uint32_t adcVal1 = (rawVal >> 5) & ((1 << 13) - 1);
const uint32_t adcVal2 = ((rawVal & 1) << 5) | ((rawVal & 2) << 3) | ((rawVal & 4) << 1) | ((rawVal & 8) >> 1) | ((rawVal & 16) >> 3) | ((rawVal & 32) >> 5);
if (adcVal1 >= 4096 || adcVal2 != (adcVal1 & ((1 << 6) - 1)))
{
lastResult = TemperatureError::badResponse;
}
else
{
lastTemperature = minLinearAdcTemp + (linearAdcDegCPerCount * (float)adcVal1);
}
}
}
// End
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