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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/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 sensorNum) noexcept
: SpiTemperatureSensor(sensorNum, "Current Loop", MCP3204_SpiMode, MCP3204_Frequency),
tempAt4mA(DefaultTempAt4mA), tempAt20mA(DefaultTempAt20mA), chipChannel(DefaultChipChannel), isDifferential(false)
{
CalcDerivedParameters();
}
// Configure this temperature sensor
GCodeResult CurrentLoopTemperatureSensor::Configure(GCodeBuffer& gb, const StringRef& reply)
{
bool seen = false;
if (!ConfigurePort(gb, reply, seen))
{
return GCodeResult::error;
}
gb.TryGetFValue('L', tempAt4mA, seen);
gb.TryGetFValue('H', tempAt20mA, seen);
gb.TryGetUIValue('C', chipChannel, seen);
gb.TryGetUIValue('D', isDifferential, seen);
TryConfigureSensorName(gb, seen);
if (seen)
{
CalcDerivedParameters();
// Initialise the sensor
InitSpi();
TemperatureError rslt;
float t;
for (unsigned int i = 0; i < 3; ++i) // try 3 times
{
rslt = TryGetLinearAdcTemperature(t);
if (lastResult == TemperatureError::success)
{
break;
}
delay(MinimumReadInterval);
}
SetResult(t, rslt);
if (rslt != TemperatureError::success)
{
reprap.GetPlatform().MessageF(ErrorMessage, "Failed to initialise daughter board ADC: %s\n", TemperatureErrorString(rslt));
}
}
else
{
CopyBasicDetails(reply);
reply.catf(", temperature range %.1f to %.1fC", (double)tempAt4mA, (double)tempAt20mA);
}
return GCodeResult::ok;
}
void CurrentLoopTemperatureSensor::Poll() noexcept
{
float t;
const TemperatureError rslt = TryGetLinearAdcTemperature(t);
SetResult(t, rslt);
}
void CurrentLoopTemperatureSensor::CalcDerivedParameters() noexcept
{
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
TemperatureError CurrentLoopTemperatureSensor::TryGetLinearAdcTemperature(float& t) noexcept
{
/*
* 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.
*
* MCP3204 & MCP3208
* Single CH0 "C0" - Differential CH0-CH1 "80"
* Single CH1 "C8" - Differential CH1-CH0 "88"
* Single CH2 "D0" - Differential CH2-CH3 "90"
* Single CH3 "D8" - Differential CH3-CH2 "98"
* MCP3208 Only
* Single CH4 "E0" - Differential CH4-CH5 "A0"
* Single CH5 "E8" - Differential CH5-CH4 "A8"
* Single CH6 "F0" - Differential CH6-CH7 "B0"
* Single CH7 "F8" - Differential CH7-CH6 "B8"
*
* These values represent clocks 1 to 5.
*/
const uint8_t channelByte = ((isDifferential) ? 0x80 : 0xC0) | (chipChannel * 0x08);
static const uint8_t adcData[] = { channelByte, 0x00, 0x00 };
uint32_t rawVal;
TemperatureError rslt = DoSpiTransaction(adcData, 3, rawVal);
//debugPrintf("ADC data %u\n", rawVal);
if (rslt == 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)))
{
rslt = TemperatureError::badResponse;
}
else
{
t = minLinearAdcTemp + (linearAdcDegCPerCount * (float)adcVal1);
}
}
return rslt;
}
// End
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