Obbart/AstroRotaxMonitor
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ADC working ok in sync with system

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This commit is contained in:
Emanuele Trabattoni
2026-04-17 11:01:41 +02:00
parent 5aa5aaa07a
commit 1b8ba88b05
5 changed files with 84 additions and 80 deletions
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66
RotaxMonitor/lib/ADS1256/ADS1256.cpp
View File

@@ -74,21 +74,21 @@ void ADS1256::InitializeADC()
writeRegister(STATUS_REG, _STATUS);
delay(200);
_MUX = 0b00000001; //MUX AIN0+AIN1
_MUX = DIFF_0_1; //MUX AIN0+AIN1
writeRegister(MUX_REG, _MUX);
delay(200);
_ADCON = 0b00000000; //ADCON - CLK: OFF, SDCS: OFF, PGA = 0 (+/- 5 V)
_ADCON = WAKEUP; //ADCON - CLK: OFF, SDCS: OFF, PGA = 0 (+/- 5 V)
writeRegister(ADCON_REG, _ADCON);
delay(200);
updateConversionParameter();
_DRATE = 0b10000010; //100SPS
_DRATE = DRATE_100SPS; //100SPS
writeRegister(DRATE_REG, _DRATE);
delay(200);
sendDirectCommand(0b11110000); //Offset and self-gain calibration
sendDirectCommand(SELFCAL); //Offset and self-gain calibration
delay(200);
_isAcquisitionRunning = false; //MCU will be waiting to start a continuous acquisition
@@ -109,7 +109,7 @@ void ADS1256::waitForHighDRDY()
void ADS1256::stopConversion() //Sending SDATAC to stop the continuous conversion
{
waitForLowDRDY(); //SDATAC should be called after DRDY goes LOW (p35. Figure 33)
_spi->transfer(0b00001111); //Send SDATAC to the ADC
_spi->transfer(SDATAC); //Send SDATAC to the ADC
CS_HIGH(); //We finished the command sequence, so we switch it back to HIGH
_spi->endTransaction();
@@ -465,7 +465,7 @@ uint8_t ADS1256::readGPIO(uint8_t gpioPin) //Reading GPIO
void ADS1256::sendDirectCommand(uint8_t directCommand)
{
//Direct commands can be found in the datasheet Page 34, Table 24.
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
CS_LOW(); //REF: P34: "CS must stay low during the entire command sequence"
delayMicroseconds(5);
@@ -486,14 +486,14 @@ void ADS1256::writeRegister(uint8_t registerAddress, uint8_t registerValueToWrit
{
waitForLowDRDY();
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
//SPI_MODE1 = output edge: rising, data capture: falling; clock polarity: 0, clock phase: 1.
CS_LOW(); //CS must stay LOW during the entire sequence [Ref: P34, T24]
delayMicroseconds(5); //see t6 in the datasheet
_spi->transfer(0x50 | registerAddress); // 0x50 = 01010000 = WREG
_spi->transfer(WREG | registerAddress); // 0x50 = 01010000 = WREG
_spi->transfer(0x00); //2nd (empty) command byte
@@ -509,18 +509,18 @@ long ADS1256::readRegister(uint8_t registerAddress) //Reading a register
{
waitForLowDRDY();
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
//SPI_MODE1 = output edge: rising, data capture: falling; clock polarity: 0, clock phase: 1.
CS_LOW(); //CS must stay LOW during the entire sequence [Ref: P34, T24]
_spi->transfer(0x10 | registerAddress); //0x10 = 0001000 = RREG - OR together the two numbers (command + address)
_spi->transfer(RREG | registerAddress); //0x10 = 0001000 = RREG - OR together the two numbers (command + address)
_spi->transfer(0x00); //2nd (empty) command byte
delayMicroseconds(5); //see t6 in the datasheet
uint8_t regValue = _spi->transfer(0xFF); //read out the register value
uint8_t regValue = _spi->transfer(0x00); //read out the register value
CS_HIGH();
_spi->endTransaction();
@@ -531,10 +531,10 @@ long ADS1256::readRegister(uint8_t registerAddress) //Reading a register
long ADS1256::readSingle() //Reading a single value ONCE using the RDATA command
{
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
CS_LOW(); //REF: P34: "CS must stay low during the entire command sequence"
waitForLowDRDY();
_spi->transfer(0b00000001); //Issue RDATA (0000 0001) command
_spi->transfer(RDATA); //Issue RDATA (0000 0001) command
delayMicroseconds(7); //Wait t6 time (~6.51 us) REF: P34, FIG:30.
_outputBuffer[0] = _spi->transfer(0); // MSB
@@ -556,10 +556,10 @@ long ADS1256::readSingleContinuous() //Reads the recently selected input channel
if(_isAcquisitionRunning == false)
{
_isAcquisitionRunning = true;
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
CS_LOW(); //REF: P34: "CS must stay low during the entire command sequence"
waitForLowDRDY();
_spi->transfer(0b00000011); //Issue RDATAC (0000 0011)
_spi->transfer(RDATAC); //Issue RDATAC (0000 0011)
delayMicroseconds(7); //Wait t6 time (~6.51 us) REF: P34, FIG:30.
}
else
@@ -585,14 +585,12 @@ long ADS1256::cycleSingle()
{
_isAcquisitionRunning = true;
_cycle = 0;
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
CS_LOW(); //CS must stay LOW during the entire sequence [Ref: P34, T24]
_spi->transfer(0x50 | 1); // 0x50 = WREG //1 = MUX
_spi->transfer(WREG | MUX_REG); // 0x50 = WREG //1 = MUX
_spi->transfer(0x00);
_spi->transfer(SING_0); //AIN0+AINCOM
CS_HIGH();
delay(50);
CS_LOW(); //CS must stay LOW during the entire sequence [Ref: P34, T24]
delayMicroseconds(250);
}
else
{}
@@ -638,18 +636,18 @@ long ADS1256::cycleSingle()
break;
}
//Step 2.
_spi->transfer(0b11111100); //SYNC
_spi->transfer(SYNC); //SYNC
delayMicroseconds(4); //t11 delay 24*tau = 3.125 us //delay should be larger, so we delay by 4 us
_spi->transfer(0b11111111); //WAKEUP
_spi->transfer(WAKEUP); //WAKEUP
//Step 3.
//Issue RDATA (0000 0001) command
_spi->transfer(0b00000001);
_spi->transfer(RDATA);
delayMicroseconds(7); //Wait t6 time (~6.51 us) REF: P34, FIG:30.
_outputBuffer[0] = _spi->transfer(0x0F); // MSB
_outputBuffer[1] = _spi->transfer(0x0F); // Mid-byte
_outputBuffer[2] = _spi->transfer(0x0F); // LSB
_outputBuffer[0] = _spi->transfer(0); // MSB
_outputBuffer[1] = _spi->transfer(0); // Mid-byte
_outputBuffer[2] = _spi->transfer(0); // LSB
_outputValue = ((long)_outputBuffer[0]<<16) | ((long)_outputBuffer[1]<<8) | (_outputBuffer[2]);
_outputValue = convertSigned24BitToLong(_outputValue);
@@ -670,16 +668,14 @@ long ADS1256::cycleDifferential()
{
_cycle = 0;
_isAcquisitionRunning = true;
_spi->beginTransaction(SPISettings(1920000, MSBFIRST, SPI_MODE1));
_spi->beginTransaction(SPISettings(SPI_FREQ, MSBFIRST, SPI_MODE1));
//Set the AIN0+AIN1 as inputs manually
CS_LOW(); //CS must stay LOW during the entire sequence [Ref: P34, T24]
_spi->transfer(0x50 | 1); // 0x50 = WREG //1 = MUX
_spi->transfer(WREG | MUX_REG); // 0x50 = WREG //1 = MUX
_spi->transfer(0x00);
_spi->transfer(DIFF_0_1); //AIN0+AIN1
CS_HIGH();
delay(50);
CS_LOW(); //CS must stay LOW during the entire sequence [Ref: P34, T24]
delayMicroseconds(250);
}
else
{}
@@ -710,12 +706,12 @@ long ADS1256::cycleDifferential()
break;
}
_spi->transfer(0b11111100); //SYNC
_spi->transfer(SYNC); //SYNC
delayMicroseconds(4); //t11 delay 24*tau = 3.125 us //delay should be larger, so we delay by 4 us
_spi->transfer(0b11111111); //WAKEUP
_spi->transfer(WAKEUP); //WAKEUP
//Step 3.
_spi->transfer(0b00000001); //Issue RDATA (0000 0001) command
_spi->transfer(RDATA); //Issue RDATA (0000 0001) command
delayMicroseconds(7); //Wait t6 time (~6.51 us) REF: P34, FIG:30.
_outputBuffer[0] = _spi->transfer(0); // MSB
@@ -744,7 +740,7 @@ void ADS1256::updateConversionParameter()
void ADS1256::updateMUX(uint8_t muxValue)
{
_spi->transfer(0x50 | MUX_REG); //Write to the MUX register (0x50 is the WREG command)
_spi->transfer(WREG | MUX_REG); //Write to the MUX register (0x50 is the WREG command)
_spi->transfer(0x00);
_spi->transfer(muxValue); //Write the new MUX value
}

3
RotaxMonitor/lib/ADS1256/ADS1256.h
View File

@@ -15,6 +15,9 @@
#include <SPI.h>
// SPI Frequency
#define SPI_FREQ 1920000
//Differential inputs
#define DIFF_0_1 0b00000001 //A0 + A1 as differential input
#define DIFF_2_3 0b00100011 //A2 + A3 as differential input