ads126x

package
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 Go to latest Published: Aug 8, 2021 License: MIT Imports: 6 Imported by: 0

Documentation

Overview

Package supports use of Texas Insturments ADS1262 and ADS1263 32-bit analog to digital converters

Index

Constants

View Source 
const (
	POWER_address byte = 0x01
	POWER_default byte = 0x11

	//reset indicator (Indicates ADC reset has occurred. Clear this bit to detect the next device reset.)
	POWER_reset_no  byte = 0b00000000
	POWER_reset_yes byte = 0b00010000

	//level shift voltage enable (Enables the internal level shift voltage to the AINCOM pin. VBIAS = (VAVDD + VAVSS)/2)
	POWER_vbias_disabled byte = 0b00000000
	POWER_vbias_enabled  byte = 0b00000010

	//Internal reference ebable (Enables the 2.5 V internal voltage reference. Note the IDAC and temperature sensor require the internal voltage reference.) This should always be enabled unless you are using an external reference
	POWER_intref_disabled byte = 0b00000000
	POWER_intref_enabled  byte = 0b00000001
)

Second register is the Power register.

View Source 
const (
	INTERFACE_address byte = 0x02
	INTERFACE_default byte = 0x05

	//Serial Interface Time-Out Enable (Enables the serial interface automatic time-out mode)
	INTERFACE_timeout_disabled byte = 0b00000000
	INTERFACE_timeout_enabled  byte = 0b00001000

	//Status Byte Enable (Enables the inclusion of the status byte during conversion data read-back)
	INTERFACE_status_disabled byte = 0b00000000
	INTERFACE_status_enabled  byte = 0b00000100

	//Checksum Byte Enable (Enables the inclusion of the checksum byte during conversion data read-back)
	INTERFACE_crc_disabled byte = 0b00000000 //checksum disabled
	INTERFACE_crc_checksum byte = 0b00000001 //checksum mode
	INTERFACE_crc_crc      byte = 0b00000010 //Cyclic redundancy check
)

Third register is the interface register. It sets serial interface timeout, status byte, and checksum byte

View Source 
const (
	MODE0_address byte = 0x03
	MODE0_default byte = 0x00

	//Reference Mux Polarity Reversal (Reverses the ADC1 reference multiplexer output polarity)
	MODE0_refrev_normalpolarity  byte = 0b00000000
	MODE0_refrev_reversepolarity byte = 0b10000000

	//ADC Conversion Run Mode (Selects the ADC conversion (run) mode)
	MODE0_runmode_continuous byte = 0b00000000 // continuous conversion
	MODE0_runmode_pulse      byte = 0b01000000 //one shot conversion

	//Chop Mode Enable (Enables the ADC chop and IDAC rotation options)
	MODE0_chop_disabled              byte = 0b00000000 //Input chop and IDAC rotation disabled
	MODE0_chop_chopenabled           byte = 0b00010000 //input chop enabled
	MODE0_chop_IDACrotation          byte = 0b00100000 //IDAC rotation enabled
	MODE0_chop_chop_and_IDACrotation byte = 0b00110000

	//Conversion Delay (Provides additional delay from conversion start to the beginning of the actual conversion)
	MODE0_delay_none  byte = 0b00000000
	MODE0_delay_8µ7s  byte = 0b00000001 //8.7 µs
	MODE0_delay_17µs  byte = 0b00000010 //17 µs
	MODE0_delay_35µs  byte = 0b00000011 //35 µs
	MODE0_delay_69µs  byte = 0b00000100 //69 µs
	MODE0_delay_139µs byte = 0b00000101 //139 µs
	MODE0_delay_278µs byte = 0b00000110 //278 µs
	MODE0_delay_555µs byte = 0b00000111 //555 µs
	MODE0_delay_1m1s  byte = 0b00001000 //1.1ms
	MODE0_delay_2m2s  byte = 0b00001001 //2.2ms
	MODE0_delay_4m4s  byte = 0b00001010 //4.4ms
	MODE0_delay_8m8s  byte = 0b00001011 //8.8ms
)

Fourth register is the Mode0 - it sets reference mux polarity, ADC conversion mode, chop mode and conversion delay.

View Source 
const (
	MODE1_address byte = 0x04
	MODE1_default byte = 0x80

	// Digital Filter (Configures the ADC digital filter)
	MODE1_filter_sinc1 byte = 0b00000000
	MODE1_filter_sinc2 byte = 0b00100000
	MODE1_filter_sinc3 byte = 0b01000000
	MODE1_filter_sinc4 byte = 0b01100000
	MODE1_filter_FIR   byte = 0b10000000 //default

	//Sensor Bias ADC Connection (Selects the ADC to connect the sensor bias)
	MODE1_sbADC_ADC1 byte = 0b00000000 //Sensor bias connected to ADC1 mux out (default)
	MODE1_sbADC_ADC2 byte = 0b00010000 //Sensor bias connected to ADC2 mux out

	//Sensor Bias Polarity Selects the sensor bias for pull-up or pull-down
	MODE1_sbpol_pullUp   byte = 0b00000000 //Sensor bias pull-up mode (AINP pulled high, AINN pulled low) (default)
	MODE1_sbpol_pullDown byte = 0b00001000 //Sensor bias pull-down mode (AINP pulled low, AINN pulled high)

	// Sensor Bias Magnitude (Selects the sensor bias current magnitude or the bias resistor)
	MODE1_sbmag_none  byte = 0b00000000 //No sensor bias current or resistor (default)
	MODE1_sbmag_500nA byte = 0b00000001 //0.5-µA sensor bias current
	MODE1_sbmag_2µA   byte = 0b00000000 //2-µA sensor bias current
	MODE1_sbmag_10µA  byte = 0b00000000 //10-µA sensor bias current
	MODE1_sbmag_50µA  byte = 0b00000000 //50-µA sensor bias current
	MODE1_sbmag_200µA byte = 0b00000000 //200-µA sensor bias current
	MODE1_sbmag_10MΩ  byte = 0b00000000 //10-MΩ resistor
)

The fifth register is Mode 1 - It sets the digital filter and Sensor Bias

View Source 
const (
	MODE2_address byte = 0x05
	MODE2_default byte = 0x04

	//PGA Bypass Mode Selects PGA bypass mode
	MODE2_bypass_PGAenabled  byte = 0b00000000 //default
	MODE2_bypass_PGAdisabled byte = 0b10000000

	//PGA Gain - selects PGA gain
	MODE2_GAIN_1  byte = 0b00000000 //1 V/V default
	MODE2_GAIN_2  byte = 0b00010000 //1 V/V
	MODE2_GAIN_4  byte = 0b00100000 //1 V/V
	MODE2_GAIN_8  byte = 0b00110000 //1 V/V
	MODE2_GAIN_16 byte = 0b01000000 //1 V/V
	MODE2_GAIN_32 byte = 0b01010000 //1 V/V

	//Data rate (Selects the ADC data rate. In FIR filter mode, the available data rates are limited to 2.5, 5, 10 and 20 SPS.)
	MODE2_DR_2_5   byte = 0b00000000 //2.5 samples per second
	MODE2_DR_5     byte = 0b00000001
	MODE2_DR_10    byte = 0b00000010
	MODE2_DR_16_6  byte = 0b00000011 //16.6~ samples per second
	MODE2_DR_20    byte = 0b00000100
	MODE2_DR_50    byte = 0b00000101
	MODE2_DR_60    byte = 0b00000110
	MODE2_DR_100   byte = 0b00000111
	MODE2_DR_400   byte = 0b00001000
	MODE2_DR_1200  byte = 0b00001001
	MODE2_DR_2400  byte = 0b00001010
	MODE2_DR_4800  byte = 0b00001011
	MODE2_DR_7200  byte = 0b00001100
	MODE2_DR_14400 byte = 0b00001101
	MODE2_DR_19200 byte = 0b00001110
	MODE2_DR_38400 byte = 0b00001111
)

The sixth register is Mode 2. It sets the PGA (programable gain amplifier) and the data rate

View Source 
const (
	INPMUX_address byte = 0x06
	INPMUX_default byte = 0x01

	//Positive Input Multiplexer (Selects the positive input multiplexer.)
	INPMUX_muxP_AIN0           byte = 0b00000000 //positive input is AIN0 (default)
	INPMUX_muxP_AIN1           byte = 0b00010000 //positive input is AIN1
	INPMUX_muxP_AIN2           byte = 0b00100000 //positive input is AIN1
	INPMUX_muxP_AIN3           byte = 0b00110000 //positive input is AIN3
	INPMUX_muxP_AIN4           byte = 0b01000000 //positive input is AIN4
	INPMUX_muxP_AIN5           byte = 0b01010000 //positive input is AIN5
	INPMUX_muxP_AIN6           byte = 0b01100000 //positive input is AIN6
	INPMUX_muxP_AIN7           byte = 0b01110000 //positive input is AIN7
	INPMUX_muxP_AIN8           byte = 0b10000000 //positive input is AIN8
	INPMUX_muxP_AIN9           byte = 0b10010000 //positive input is AIN9
	INPMUX_muxP_AINCOM         byte = 0b10100000 //positive input is AINCOM
	INPMUX_muxP_tempSensorP    byte = 0b10110000 //Temperature sensor monitor positive
	INPMUX_muxP_analogSupplyP  byte = 0b11000000 //Analog power supply monitor positive
	INPMUX_muxP_digitalSupplyP byte = 0b11010000 //Digital power supply monitor positive
	INPMUX_muxP_TDACP          byte = 0b11100000 //TDAC test signal positive
	INPMUX_muxP_float          byte = 0b11110000 //Float (open connection)

	INPMUX_muxN_AIN0           byte = 0b00000000 //negative input is AIN0
	INPMUX_muxN_AIN1           byte = 0b00000001 //negative input is AIN1 (default)
	INPMUX_muxN_AIN2           byte = 0b00000010 //negative input is AIN2
	INPMUX_muxN_AIN3           byte = 0b00000011 //negative input is AIN3
	INPMUX_muxN_AIN4           byte = 0b00000100 //negative input is AIN4
	INPMUX_muxN_AIN5           byte = 0b00000101 //negative input is AIN5
	INPMUX_muxN_AIN6           byte = 0b00000110 //negative input is AIN6
	INPMUX_muxN_AIN7           byte = 0b00000111 //negative input is AIN7
	INPMUX_muxN_AIN8           byte = 0b00001000 //negative input is AIN8
	INPMUX_muxN_AIN9           byte = 0b00001001 //negative input is AIN9
	INPMUX_muxN_AINCOM         byte = 0b00001010 //negative input is AINCOM
	INPMUX_muxN_tempSensorN    byte = 0b00001011 //Temperature sensor monitor negative
	INPMUX_muxN_analogSupplyN  byte = 0b00001100 //Analog power supply monitor negative
	INPMUX_muxN_digitalSupplyN byte = 0b00001101 //Digital power supply monitor negative
	INPMUX_muxN_TDACP          byte = 0b00001110 //TDAC test signal negative
	INPMUX_muxN_float          byte = 0b00001111 //Float (open connection)
)

The input multiplexer register sets the input channels

View Source 
const (
	OFCAL0_address byte = 0x07
	OFCAL1_address byte = 0x08
	OFCAL2_address byte = 0x09
)

Offset calibration register - Use calibration to correct internal ADC errors or overall system errors. the value of the offset calibration register is subtracted from the filter output and then multiplied by the full-scale register value divided by 400000h. The data are then clipped to a 32-bit value to provide the final output. (see section 9.4.9 of the datasheet for more information)

View Source 
const (
	FSCAL0_address byte = 0x0A
	FSCAL1_address byte = 0x0B
	FSCAL2_address byte = 0x0C
)

Full-scale calibration register - Use calibration to correct internal ADC errors or overall system errors. the value of the offset calibration register is subtracted from the filter output and then multiplied by the full-scale register value divided by 400000h. The data are then clipped to a 32-bit value to provide the final output. (see section 9.4.9 of the datasheet for more information)

View Source 
const (
	IDACMUX_address byte = 0x0D
	IDACMUX_default byte = 0xBB

	//IDAC2 Output Multiplexer Selects the analog input pin to connect IDAC2
	IDACMUX_mux2_AIN0   byte = 0b00000000 //IDAC2 output is AIN0
	IDACMUX_mux2_AIN1   byte = 0b00010000 //IDAC2 output is AIN1
	IDACMUX_mux2_AIN2   byte = 0b00100000 //IDAC2 output is AIN1
	IDACMUX_mux2_AIN3   byte = 0b00110000 //IDAC2 output is AIN3
	IDACMUX_mux2_AIN4   byte = 0b01000000 //IDAC2 output is AIN4
	IDACMUX_mux2_AIN5   byte = 0b01010000 //IDAC2 output is AIN5
	IDACMUX_mux2_AIN6   byte = 0b01100000 //IDAC2 output is AIN6
	IDACMUX_mux2_AIN7   byte = 0b01110000 //IDAC2 output is AIN7
	IDACMUX_mux2_AIN8   byte = 0b10000000 //IDAC2 output is AIN8
	IDACMUX_mux2_AIN9   byte = 0b10010000 //IDAC2 output is AIN9
	IDACMUX_mux2_AINCOM byte = 0b10100000 //IDAC2 output is AINCOM
	IDACMUX_mux2_none   byte = 0b10110000 //No connection (default)

	//IDAC1 Output Multiplexer Selects the analog input pin to connect IDAC1
	IDACMUX_mux1_AIN0   byte = 0b00000000 //IDAC1 output is AIN0
	IDACMUX_mux1_AIN1   byte = 0b00000001 //IDAC1 output is AIN1
	IDACMUX_mux1_AIN2   byte = 0b00000010 //IDAC1 output is AIN2
	IDACMUX_mux1_AIN3   byte = 0b00000011 //IDAC1 output is AIN3
	IDACMUX_mux1_AIN4   byte = 0b00000100 //IDAC1 output is AIN4
	IDACMUX_mux1_AIN5   byte = 0b00000101 //IDAC1 output is AIN5
	IDACMUX_mux1_AIN6   byte = 0b00000110 //IDAC1 output is AIN6
	IDACMUX_mux1_AIN7   byte = 0b00000111 //IDAC1 output is AIN7
	IDACMUX_mux1_AIN8   byte = 0b00001000 //IDAC1 output is AIN8
	IDACMUX_mux1_AIN9   byte = 0b00001001 //IDAC1 output is AIN9
	IDACMUX_mux1_AINCOM byte = 0b00001010 //IDAC1 output is AINCOM
	IDACMUX_mux1_none   byte = 0b00001011 //No connection (default)

)

IDAC Multiplexer register - selects analog input pins to connect to IDAC1 and IDAC2 (IDAC refers to current sources)

View Source 
const (
	IDACMAG_address byte = 0x0E
	IDACMAG_default byte = 0x00
	//IDAC2 Output Multiplexer Selects the analog input pin to connect IDAC2
	IDACMAG_mag2_off  byte = 0b00000000 //IDAC2 is off (default)
	IDACMAG_mag2_50   byte = 0b00010000 //IDAC2 output is 50 µA
	IDACMAG_mag2_100  byte = 0b00100000 //IDAC2 output is 100 µA
	IDACMAG_mag2_250  byte = 0b00110000 //IDAC2 output is 250 µA
	IDACMAG_mag2_500  byte = 0b01000000
	IDACMAG_mag2_750  byte = 0b01010000
	IDACMAG_mag2_1000 byte = 0b01100000
	IDACMAG_mag2_1500 byte = 0b01110000
	IDACMAG_mag2_2000 byte = 0b10000000
	IDACMAG_mag2_3000 byte = 0b10010000

	//IDAC1 Output Multiplexer Selects the analog input pin to connect IDAC1
	IDACMAG_mag1_off  byte = 0b00000000 //IDAC1 is off
	IDACMAG_mag1_50   byte = 0b00000001 //IDAC1 output is 50 µA
	IDACMAG_mag1_100  byte = 0b00000010 //IDAC1 output is 100 µA
	IDACMAG_mag1_250  byte = 0b00000011 //IDAC1 output is 250 µA
	IDACMAG_mag1_500  byte = 0b00000100
	IDACMAG_mag1_750  byte = 0b00000101
	IDACMAG_mag1_1000 byte = 0b00000110
	IDACMAG_mag1_1500 byte = 0b00000111
	IDACMAG_mag1_2000 byte = 0b00001000
	IDACMAG_mag1_2500 byte = 0b00001001
	IDACMAG_mag1_3000 byte = 0b00001010
)

IDAC magnitude register (IDAC refers to current sources)

View Source 
const (
	REFMUX_address byte = 0x0F
	REFMUX_default byte = 0x00
	//Reference Positive Input (Selects the positive reference input)
	REFMUX_rmuxP_internalRef   byte = 0b00000000 //Internal 2.5 V reference - P (default)
	REFMUX_rmuxP_AIN0          byte = 0b00001000 //External AIN0
	REFMUX_rmuxP_AIN2          byte = 0b00010000
	REFMUX_rmuxP_AIn4          byte = 0b00011000
	REFMUX_rmuxP_internalVavdd byte = 0b00100000 // Internal analog supply (VAVDD )
	//Reference Negative Input (Selects the negative reference input)
	REFMUX_rmuxN_internalRef   byte = 0b00000000 //Internal 2.5 V reference - N (default)
	REFMUX_rmuxN_AIN1          byte = 0b00000001 //External AIN1
	REFMUX_rmuxN_AIN3          byte = 0b00000010
	REFMUX_rmuxN_AIN5          byte = 0b00000011
	REFMUX_rmuxP_internalVavss byte = 0b00000100 //Internal analog supply (VAVSS)
)

Reference multiplexer register - selects reference inputs

View Source 
const (
	TDACP_address byte = 0x10
	TDACP_default byte = 0x00
	// TDACP Output Connection (Connects TDACP output to pin AIN6)
	TDACP_outP_none byte = 0b00000000
	TDACP_outP_AIN6 byte = 0b10000000
	// MAGP Output Magnitude Select the TDACP output magnitude. (The TDAC output voltages are ideal and are with respect to VAVSS)
	TDACP_magP_4_5       byte = 0b00001001 // 4.5 V
	TDACP_magP_3_5       byte = 0b00001000 // 3.5 V
	TDACP_magP_3         byte = 0b00000111 // 3 V
	TDACP_magP_2_75      byte = 0b00000110 // 2.75 V
	TDACP_magP_2_625     byte = 0b00000101 // 2.625 v
	TDACP_magP_2_5626    byte = 0b00000100 // 2.5625 V
	TDACP_magP_2_53125   byte = 0b00000011 // 2.53125 V
	TDACP_magP_2_515625  byte = 0b00000010 // 2.515625 V
	TDACP_magP_2_5078125 byte = 0b00000001 // 2.5078125 V
	TDACP_magP_2_5       byte = 0b00000000 // 2.5 V
	TDACP_magP_2_4921875 byte = 0b00010001 // 2.4921875 V
	TDACP_magP_2_484375  byte = 0b00010010 // 2.484375 V
	TDACP_magP_2_46875   byte = 0b00010011 // 2.46875 V
	TDACP_magP_2_4375    byte = 0b00010100 // 2.4375 V
	TDACP_magP_2_375     byte = 0b00010101 // 2.375 V
	TDACP_magP_2_25      byte = 0b00010110 // 2.25 V
	TDACP_magP_2         byte = 0b00010111 // 2 V
	TDACP_magP_1_5       byte = 0b00011000 // 1.5 V
	TDACP_magP_0_5       byte = 0b00011001 // 0.5 V
)

TDACP control register - Test DAC (positive)

View Source 
const (
	TDACN_address byte = 0x10
	TDACN_default byte = 0x00
	// TDACN Output Connection (Connects TDACN output to pin AIN6)
	TDACN_outN_none byte = 0b00000000
	TDACN_outN_AIN7 byte = 0b10000000
	// MAGN Output Magnitude Select the TDACN output magnitude. (The TDAC output voltages are ideal and are with respect to VAVSS)
	TDACN_magN_4_5       byte = 0b00001001 // 4.5 V
	TDACN_magN_3_5       byte = 0b00001000 // 3.5 V
	TDACN_magN_3         byte = 0b00000111 // 3 V
	TDACN_magN_2_75      byte = 0b00000110 // 2.75 V
	TDACN_magN_2_625     byte = 0b00000101 // 2.625 v
	TDACN_magN_2_5626    byte = 0b00000100 // 2.5625 V
	TDACN_magN_2_53125   byte = 0b00000011 // 2.53125 V
	TDACN_magN_2_515625  byte = 0b00000010 // 2.515625 V
	TDACN_magN_2_5078125 byte = 0b00000001 // 2.5078125 V
	TDACN_magN_2_5       byte = 0b00000000 // 2.5 V
	TDACN_magN_2_4921875 byte = 0b00010001 // 2.4921875 V
	TDACN_magN_2_484375  byte = 0b00010010 // 2.484375 V
	TDACN_magN_2_46875   byte = 0b00010011 // 2.46875 V
	TDACN_magN_2_4375    byte = 0b00010100 // 2.4375 V
	TDACN_magN_2_375     byte = 0b00010101 // 2.375 V
	TDACN_magN_2_25      byte = 0b00010110 // 2.25 V
	TDACN_magN_2         byte = 0b00010111 // 2 V
	TDACN_magN_1_5       byte = 0b00011000 // 1.5 V
	TDACN_magN_0_5       byte = 0b00011001 // 0.5 V
)

TDACN control register - Test DAC (negative)

View Source 
const (
	ID_address byte = 0x00
)

First register is the Device identification register which is read only. Reading this register gives device version and revision.

View Source 
const RDATA1 byte = 0x12

Read ADC1 data (opcode)

View Source 
const RESET byte = 0x06

Reset the ADC (opcode)

View Source 
const RREG byte = 0x20

Read registers (opcode)

View Source 
const SFOCAL1 byte = 0x19

ADC1 self offset calibration (opcode)

View Source 
const START1 byte = 0x08

Start ADC1 conversions (opcode)

View Source 
const STOP1 byte = 0x0A

Stop ADC1 conversions (opcode)

View Source 
const SYGCAL1 byte = 0x17

ADC1 system gain calibration (opcode)

View Source 
const SYOCAL1 byte = 0x16

ADC1 system offset calibration (opcode)

View Source 
const WREG byte = 0x40

Opcodes - Commands are used to access the configuration and data registers and also to control the ADC. Many of the ADC commands are stand-alone (that is, single-byte). The register write and register read commands, however, are multibyte, consisting of two opcode bytes plus the register data byte or bytes. (see section 9.5 of the datasheet) Write registers (opcode)

Variables

This section is empty.

Functions

func ContinuousReadCHK 

func ContinuousReadCHK(connection spi.Conn, drdy gpio.PinIO) (int32, error)

This function requires that the checksum be enabled in checksum mode and the status byte enabled. It reads the data in continuous mode - meaning that it waits for the data ready signal on the DRDY pin and then begins reading. The output is an unconverted 32 bit integer. If the checksum fails, SPI fails, or DRDY pin times out it will output an error and a value of zero.

func ConvertData 

func ConvertData(data int32) float64

This converts the output of the read function to a voltage between -2.5 and 2.5. It does not account for gain.

func InitSetupNoStartPin 

func InitSetupNoStartPin(connection spi.Conn, start gpio.PinIO, pwdn gpio.PinIO)

alternative function to restart the ADS126x using the STOP1 command - Use this instead of InitSetup if you are not using the START pin. It is based on fig 159 from the datasheet. Make sure this comes after the SPI connection is initialized since it used to send the stop command

func ReadByCommandCHK 

func ReadByCommandCHK(connection spi.Conn, drdy gpio.PinIO) (int32, error)

func Restart 

func Restart(start, pwdn gpio.PinIO)

function to restart the ADS126x based on fig 159 from the datasheet

func Startcommand 

func Startcommand(connection spi.Conn)

func Stopcommand 

func Stopcommand(connection spi.Conn)

Types

This section is empty.

Source Files

View all Source files

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