ADS126X

A class to control the TI ADS1262 and ADS1263 analog to digital converters. This basically includes all functions of these two chips. Check the examples if it seems too complicated.

Note that all commands dealing with ACD2 are for the ADS1263 only, and have not been tested by me.

I tried to keep all commands in the order the datasheet is written in for ease of reading. Basic commands are on page 85, the register map is on page 88.

Table of Contents

• Initialization
  • ADS126X
  • begin(chip_select)
  • begin
  • setStartPin
• General Commands
  • noOperation
  • reset
  • startADC1
  • stopADC1
  • startADC2
  • stopADC2
• Analog Read Functions
  • readADC1
  • readADC2
• Calibration Functions
  • calibrateSysOffsetADC1
  • calibrateGainADC1
  • calibrateSelfOffsetADC1
  • calibrateSysOffsetADC2
  • calibrateGainADC2
  • calibrateSelfOffsetADC2
• Power Functions
  • checkResetBit
  • clearResetBit
  • enableLevelShift
  • disableLevelShift
  • enableInternalReference
  • disableInternalReference
• Checksum Functions
  • disableCheck
  • setChecksumMode
  • setCRCMode
  • lastChecksum
• Status Functions
  • enableStatus
  • disableStatus
  • lastStatus
  • lastADC2Status
  • lastADC1Status
  • lastClockSource
  • lastADC1LowReferenceAlarm
  • lastADC1PGAOutputLowAlarm
  • lastADC1PGAOutputHighAlarm
  • lastADC1PGADifferentialOutputAlarm
  • lastReset
• Mode0 Functions
  • setContinuousMode
  • setPulseMode
  • setChopMode
  • setDelay
• Mode1 Functions
  • setFilter
  • setBiasADC
  • setBiasPolarity
  • setBiasMagnitude
• Mode2 Functions
  • enablePGA
  • bypassPGA
  • setGain
  • setRate
  • setReference
• GPIO Functions
  • gpioConnect
  • gpioDisconnect
  • gpioDirection
  • gpioWrite
  • gpioRead

Initialization

ADS126X

Starts the class.

void begin(uint8_t chip_select)

Sets up the chip and Arduino for usage. It also resets the chip. uint8_t chip_select is the Arduino pin used to start communication with the chip.

void begin()

The same as the above function, but without the chip select. If you use this, tie the CS pin on the chip to ground. I don't recommend using this.

void setStartPin(uint8_t pin)

Optional. Designate an Arduino pin to start ADC1. If not used, a command will be sent instead.

General Commands

void noOperation()

Tells the chip to stop everything. Future commands will wake it back up.

void reset()

Resets the chip.

void startADC1()

Starts conversion on ADC1.

void stopADC1()

Stops conversion on ADC1.

void startADC2()

Starts conversion on ADC2.

void stopADC2()

Stops conversion on ADC2.

Analog Read Functions

int32_t readADC1(uint8_t pos_pin,uint8_t neg_pin)

Reads the 32 bit voltage between the two pins pos_pin and neg_pin. These can be:

Option	Description
0 or ADS126X_AIN0	Pin AIN0
...	...
9 or ADS126X_AIN9	Pin AIN9
ADS126X_AINCOM	Pin AINCOM
ADS126X_TEMP	Temperature sensor monitor positive/negative
ADS126X_ANALOG	Analog power supply monitor positive/negative
ADS126X_DIGITAL	Digital power supply monitor positive/negative
ADS126X_TDAC	TDAC test signal positive/negative
ADS126X_FLOAT	Float (open connection)

int32_t readADC2(uint8_t pos_pin,uint8_t neg_pin)

Reads the 24 bit voltage between the two pins pos_pin and neg_pin. These can be:

Option	Description
0 or ADS126X_AIN0	Pin AIN0
...	...
9 or ADS126X_AIN9	Pin AIN9
ADS126X_AINCOM	Pin AINCOM
ADS126X_TEMP	Temperature sensor monitor positive/negative
ADS126X_ANALOG	Analog power supply monitor positive/negative
ADS126X_DIGITAL	Digital power supply monitor positive/negative
ADS126X_TDAC	TDAC test signal positive/negative
ADS126X_FLOAT	Float (open connection)

Calibration Functions

void calibrateSysOffsetADC1(uint8_t shorted1,uint8_t shorted2)

Calibrates the system offset on ADC1. Short the pins externally, then run this command. Options can be:

Option	Description
0 or ADS126X_AIN0	Pin AIN0
...	...
9 or ADS126X_AIN9	Pin AIN9

void calibrateGainADC1(uint8_t vcc_pin,uint8_t gnd_pin)

Calibrates the PGA on ADC1. vcc_pin should be connected to the maximum analog voltage,gnd_pin to analog ground. Options can be:

Option	Description
0 or ADS126X_AIN0	Pin AIN0
...	...
9 or ADS126X_AIN9	Pin AIN9

void calibrateSelfOffsetADC1()

Calibrates the self offset on ADC1.

void calibrateSysOffsetADC2(uint8_t shorted1,uint8_t shorted2)

Calibrates the system offset on ADC2. Short the pins externally, then run this command. Options can be:

Option	Description
0 or ADS126X_AIN0	Pin AIN0
...	...
9 or ADS126X_AIN9	Pin AIN9

void calibrateGainADC2(uint8_t vcc_pin,uint8_t gnd_pin)

Calibrates the PGA on ADC2. vcc_pin should be connected to the maximum analog voltage,gnd_pin to analog ground. Options can be:

Option	Description
0 or ADS126X_AIN0	Pin AIN0
...	...
9 or ADS126X_AIN9	Pin AIN9

void calibrateSelfOffsetADC2()

Calibrates the self offset on ADC2.

Power Functions

I didn't know what else to call this category. All functions have to do with the POWER register.

bool checkResetBit()

Indicates ADC reset has occurred. If 1, a new reset has occured. This should be 1 at start.

void clearResetBit()

Sets the reset bit to 0.

void enableLevelShift()

Enables the internal level shift voltage to the AINCOM pin. Default disabled. VBIAS = (V_AVDD + V_AVSS)/2

void disableLevelShift()

Disables the internal level shift voltage to the AINCOM pin. Default disabled. VBIAS = (V_AVDD + V_AVSS)/2

void enableInternalReference()

Enables the 2.5V internal voltage reference. Note the IDAC and temperature sensor require the internal voltage reference. Enabled by default.

void disableInternalReference()

Disables the 2.5V internal voltage reference. Note the IDAC and temperature sensor require the internal voltage reference. Enabled by default.

Checksum Functions

If enabled, the chip will send a checksum during a voltage read to verify the data was sent correctly. These functions will set the mode, and return the verification.

void disableCheck()

Disable the checksum.

void setChecksumMode()

Make the device return a checksum value.

void setCRCMode()

Make the device return a CRC value.

bool lastChecksum()

Return the computed last checksum/CRC value. If 0, the data was transmitted correctly.

Status Functions

If enabled, the chip will send the status of various parameters as part of each voltage read. All functions below will use the most recent status sent from the chip.

void enableStatus()

Enables the chip sending the status. Default enabled.

void disableStatus()

Disables the chip sending the status.

uint8_t lastStatus()

Returns the most recent status byte. More for debugging than anything.

bool lastADC2Status()

If 1, ADC2 data is new since the last ADC2 read operation.

bool lastADC1Status()

If 1, ADC1 data is new since the last ADC1 read operation.

bool lastClockSource()

If 0, ADC clock is internal. If 1, ADC clock is external.

bool lastADC1LowReferenceAlarm()

This is the low reference voltage alarm of ADC1. The alarm bit is set if V_REF <= 0.4V, typical. If 0, no alarm. If 1, low reference alarm.

bool lastADC1PGAOutputLowAlarm()

This is the ADC1 PGA absolute low voltage alarm. The bit is set if the absolute voltage of either PGA output is less than V_AVSS + 0.2V. See the PGA Absolute Output-Voltage Monitor section of the datasheet. If 0, no alarm If 1, PGA high voltage alarm

bool lastADC1PGAOutputHighAlarm()

This is the ADC1 PGA absolute high voltage alarm. The bit is set if the absolute voltage of either PGA output is greater than V_AVDD - 0.2V. See the PGA Absolute Output-Voltage Monitor section of the datasheet. If 0, no alarm If 1, PGA high voltage alarm

bool lastADC1PGADifferentialOutputAlarm()

This is the ADC1 PGA differential output range alarm. This bit is set if the PGA differential output voltage exceeds +105% FS or -105% FS. See the PGA Differential Output Monitor section of the datasheet. If 0, no alarm If 1, PGA differential range alarm

bool lastReset()

Indicates device reset. Device reset occurs at power-on, by the RESET/PWDN pin or by the reset command. This bit is the same as the RESET bit of the POWER register. If 0, no reset occurred since the RESET bit in power register last cleared by the user. If 1, device reset occurred

Mode0 Functions

Functions having to do with the MODE0 register.

void setContinuousMode()

Puts the device into continuous read mode. Default.

void setPulseMode()

Puts the device into pulse read mode. Normally you would need to call the startADC* function before every readADC* in this mode, but I have it automatically called.

void setChopMode(uint8_t mode)

Enables the ADC chop and ICAD rotation options.

Option	Description
ADS126X_CHOP_0	Input chop and IDAC rotation disabled (default)
ADS126X_CHOP_1	Input chop enabled
ADS126X_CHOP_2	IDAC rotaion enabled
ADS126X_CHOP_3	Input chop and IDAC rotation enabled

void setDelay(uint8_t del)

Provides additional delay from conversion start to the beginning of the actual conversion. Default no delay.

Option	Delay
ADS126X_DELAY_0	No delay
ADS126X_DELAY_8700	8.7 s
ADS126X_DELAY_17000	17 s
ADS126X_DELAY_35000	35 s
ADS126X_DELAY_69000	69 s
ADS126X_DELAY_139000	139 s
ADS126X_DELAY_278000	278 s
ADS126X_DELAY_555000	555 s
ADS126X_DELAY_1_1	1.1 ms
ADS126X_DELAY_2_2	2.2 ms
ADS126X_DELAY_4_4	4.4 ms
ADS126X_DELAY_8_8	8.8 ms

Mode1 Functions

Functions having to do with the MODE1 register.

void setFilter(uint8_t filter)

Configures the ADC digital filter. Detailed description can be found starting on page 45.

Option	Description
ADS126X_SINC1	Sinc1 mode
ADS126X_SINC2	Sinc2 mode
ADS126X_SINC3	Sinc3 mode
ADS126X_SINC4	Sinc4 mode
ADS126X_FIR	FIR mode (default)

void setBiasADC(uint8_t adc_choice)

Selects the ADC to connect the sensor bias.

Option	Description
0 or ADS126X_BIAS_ADC1	Sensor bias connected to ADC1 mux out (default)
1 or ADS126X_BIAS_ADC2	Sensor bias connected to ADC2 mux out

void setBiasPolarity(uint8_t polarity)

Selects the sensor bias polarity for pull-up or pull-down

Option	Sensor bias pull-up mode
0 or ADS126X_BIAS_PULLUP	AIN_P pulled high, AIN_N pulled low (default)
1 or ADS126X_BIAS_PULLDOWN	AIN_P pulled low, AIN_N pulled high

void setBiasMagnitude(uint8_t mag)

Selects the sensor bias current magnitude or the bias resistor

Option	Description
ADS126X_BIAS_MAG_0	No sensor bias current or resistor (default)
ADS126X_BIAS_MAG_0_5	0.5 A sensor bias current
ADS126X_BIAS_MAG_2	2 A sensor bias current
ADS126X_BIAS_MAG_10	10 A sensor bias current
ADS126X_BIAS_MAG_50	50 A sensor bias current
ADS126X_BIAS_MAG_200	200 A sensor bias current
ADS126X_BIAS_MAG_10M	10 MOhm resistor

Mode2 Functions

void enablePGA()

Enables the PGA, default

void bypassPGA()

PGA bypassed

void setGain(uint8_t gain)

Selects the PGA gain

Option	Gain
ADS126X_GAIN_1	1 V/V
ADS126X_GAIN_2	2 V/V
ADS126X_GAIN_4	4 V/V
ADS126X_GAIN_8	8 V/V
ADS126X_GAIN_16	16 V/V
ADS126X_GAIN_32	32 V/V

void setRate(uint8_t rate)

Selects the ADC data rate. In FIR filter mode, the available data rates are limited to 2.5, 5, 10, and 20 FPS. This class does NOT make sure you set that up right.

Option	Speed
ADS126X_RATE_2_5	2.5 SPS
ADS126X_RATE_5	5 SPS
ADS126X_RATE_10	10 SPS
ADS126X_RATE_16_6	16.6 SPS
ADS126X_RATE_20	20 SPS
ADS126X_RATE_50	50 SPS
ADS126X_RATE_60	60 SPS
ADS126X_RATE_100	100 SPS
ADS126X_RATE_400	400 SPS
ADS126X_RATE_1200	1200 SPS
ADS126X_RATE_2400	2400 SPS
ADS126X_RATE_4800	4800 SPS
ADS126X_RATE_7200	7200 SPS
ADS126X_RATE_14400	14400 SPS
ADS126X_RATE_19200	19200 SPS
ADS126X_RATE_38400	38400 SPS

void setReference(uint8_t negativeReference, uint8_t positiveReference)

Selects the positive and negative references.

Option - Negative	Reference
ADS126X_REF_NEG_INT	INTERNAL
ADS126X_REF_NEG_AIN1	AIN1
ADS126X_REF_NEG_AIN3	AIN3
ADS126X_REF_NEG_AIN5	AIN5
ADS126X_REF_NEG_VSS	VSS

Option - Positive	Reference
ADS126X_REF_POS_INT	INTERNAL
ADS126X_REF_POS_AIN0	AIN0
ADS126X_REF_POS_AIN2	AIN2
ADS126X_REF_POS_AIN4	AIN4
ADS126X_REF_POS_VDD	VDD

GPIO Functions

These all pertain to the gpio pins on the chip.

For all of them, there is an input uint8_t pin. This is the gpio pin that you want to use. Map:

PinCode (uint8_t pin)	External Pin
0	AIN3
1	AIN4
2	AIN5
3	AIN6
4	AIN7
5	AIN8
6	AIN9
7	AINCOM

void gpioConnect(uint8_t pin)

Connect the gpio pin to the external pin

void gpioDisconnect(uint8_t pin)

Disconnect the gpio pin from the external pin

void gpioDirection(uint8_t pin,uint8_t direction)

Configures the pin as output or input. All are set to output by default.

Option	Description
0 or ADS126X_GPIO_OUTPUT	Configure pin as output
1 or ADS126X_GPIO_INPUT	Configure pin as input

void gpioWrite(uint8_t pin,uint8_t val)

Writes a value to a pin configured as output.

Option	Description
0 or ADS126X_GPIO_LOW	Set pin low
1 or ADS126X_GPIO_HIGH	Set pin high

bool gpioRead(uint8_t pin)

Reads the value of a pin configured as input.

Returns 0 if low Returns 1 if high