IDT Optical Sensors
ADS1256 program
Revision 0:897d3bb0accd, committed 2017-12-01
- Comitter:
- laserdad
- Date:
- Fri Dec 01 21:31:48 2017 +0000
- Commit message:
- last known version;
Changed in this revision
| ADS1256.cpp | Show annotated file Show diff for this revision Revisions of this file |
| ADS1256.h | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ADS1256.cpp Fri Dec 01 21:31:48 2017 +0000
@@ -0,0 +1,582 @@
+#include "ADS1256.h"
+
+extern Serial pc;
+
+ADS1256::ADS1256(SPI *spi_itf, DigitalIn *nrdy_pin, DigitalOut *cs_pin)
+{
+ spi = spi_itf;
+ cs = cs_pin;
+ nrdy = nrdy_pin;
+ *cs = 1; // Assert CS high
+ setSpi();
+ scanMode = 1;
+ gain = 0; /* GAIN */
+ dataRate = 15; /* DATA output speed*/
+ buffer_en = 1;
+ channel=0;
+ getMaxWaitDelay_us();
+};
+
+uint8_t ADS1256::getGainVal(void)
+{
+ return (1<<gain); //e.g. 1,2,4,8,16,32,64
+}
+
+
+void ADS1256::setSpi(void)
+{
+ spi->format(8, ADS1256_SPI_MODE);
+ spi->frequency(1800000);
+}
+
+
+
+/*
+*********************************************************************************************************
+* name: CfgADC
+* function: The configuration parameters of ADC gain, data rate and internal buffer;
+* parameter: gain: 0-5 (1-64)
+* dataRate: 0-16 (2.5-30000 sps)
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::cfgADC(void)
+{
+ static const uint8_t s_tabDataRate[16] =
+ {
+ 0x03,
+ 0x13,
+ 0x20,
+ 0x33,
+ 0x43,
+ 0x53,
+ 0x63,
+ 0x72,
+ 0x82,
+ 0x92,
+ 0xA1,
+ 0xB0,
+ 0xC0,
+ 0xD0,
+ 0xE0,
+ 0xF0 /*reset value */
+ };
+
+ waitDRDY();
+
+
+ uint8_t buf[4]; /* Storage ads1256 register configuration parameters */
+
+ /*Status register define
+ Bits 7-4 ID3, ID2, ID1, ID0 Factory Programmed Identification Bits (Read Only)
+
+ Bit 3 ORDER: Data Output Bit Order
+ 0 = Most Significant Bit First (default)
+ 1 = Least Significant Bit First
+ Input data is always shifted in most significant byte and bit first. Output data is always shifted out most significant
+ byte first. The ORDER bit only controls the bit order of the output data within the byte.
+
+ Bit 2 ACAL : Auto-Calibration
+ 0 = Auto-Calibration Disabled (default)
+ 1 = Auto-Calibration Enabled
+ When Auto-Calibration is enabled, self-calibration begins at the completion of the WREG command that changes
+ the PGA (bits 0-2 of ADCON register), DR (bits 7-0 in the DRATE register) or BUFEN (bit 1 in the STATUS register)
+ values.
+
+ Bit 1 BUFEN: Analog Input Buffer Enable
+ 0 = Buffer Disabled (default)
+ 1 = Buffer Enabled
+
+ Bit 0 DRDY : Data Ready (Read Only)
+ This bit duplicates the state of the DRDY pin.
+
+ ACAL=1 enable calibration
+ */
+ buf[0] = (0 << 3) | (1 << 2) | ( (buffer_en & 0x01) << 1);//enable the internal buffer
+// buf[0] = (0 << 3) | (1 << 2) | (0 << 1); // The internal buffer is prohibited
+
+ //WriteReg(REG_STATUS, (0 << 3) | (1 << 2) | (1 << 1));
+
+ buf[1] = 0x08;
+
+ /* ADCON: A/D Control Register (Address 02h)
+ Bit 7 Reserved, always 0 (Read Only)
+ Bits 6-5 CLK1, CLK0 : D0/CLKOUT Clock Out Rate Setting
+ 00 = Clock Out OFF
+ 01 = Clock Out Frequency = fCLKIN (default)
+ 10 = Clock Out Frequency = fCLKIN/2
+ 11 = Clock Out Frequency = fCLKIN/4
+ When not using CLKOUT, it is recommended that it be turned off. These bits can only be reset using the RESET pin.
+
+ Bits 4-3 SDCS1, SCDS0: Sensor Detect Current Sources
+ 00 = Sensor Detect OFF (default)
+ 01 = Sensor Detect Current = 0.5 ¦Ì A
+ 10 = Sensor Detect Current = 2 ¦Ì A
+ 11 = Sensor Detect Current = 10¦Ì A
+ The Sensor Detect Current Sources can be activated to verify the integrity of an external sensor supplying a signal to the
+ ADS1255/6. A shorted sensor produces a very small signal while an open-circuit sensor produces a very large signal.
+
+ Bits 2-0 PGA2, PGA1, PGA0: Programmable Gain Amplifier Setting
+ 000 = 1 (default)
+ 001 = 2
+ 010 = 4
+ 011 = 8
+ 100 = 16
+ 101 = 32
+ 110 = 64
+ 111 = 64
+ */
+ buf[2] = (0 << 5) | (0 << 3) | ( (gain & 0x07) << 0);
+ //WriteReg(REG_ADCON, (0 << 5) | (0 << 2) | (GAIN_1 << 1)); /*choose 1: gain 1 ;input 5V/
+ buf[3] = s_tabDataRate[dataRate]; // DRATE_10SPS;
+
+ *cs = 0; /* SPICS¡ = 0 */
+ spi->write(CMD_WREG | 0); /* Write command register, send the register address */
+ spi->write(0x03); /* Register number 4,Initialize the number -1*/
+
+ spi->write(buf[0]); /* Set the status register */
+ spi->write(buf[1]); /* Set the input channel parameters */
+ spi->write(buf[2]); /* Set the ADCON control register,gain */
+ spi->write(buf[3]); /* Set the output rate */
+
+ *cs =1; /* SPI cs = 1 */
+
+
+ wait_us(50);
+ getMaxWaitDelay_us();
+}
+
+
+/*
+*********************************************************************************************************
+* name: DelayDATA
+* function: delay
+* parameter: NULL
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::delayDATA(void)
+{
+ /*
+ Delay from last SCLK edge for DIN to first SCLK rising edge for DOUT: RDATA, RDATAC,RREG Commands
+ min 50 CLK = 50 * 0.13uS = 6.5uS
+ */
+ wait_us(10); /* The minimum time delay 6.5us */
+}
+
+
+
+
+/*
+*********************************************************************************************************
+* name: WriteReg
+* function: Write the corresponding register
+* parameter: _RegID: register ID
+* _RegValue: register Value
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::writeReg(uint8_t _RegID, uint8_t _RegValue)
+{
+ *cs = 0; /* SPI cs = 0 */
+ spi->write(CMD_WREG | _RegID); /*Write command register */
+ spi->write(0x00); /*Write the register number */
+
+ spi->write(_RegValue); /*send register value */
+ *cs =1; /* SPI cs = 1 */
+}
+
+/*
+*********************************************************************************************************
+* name: ReadReg
+* function: readVal the corresponding register
+* parameter: _RegID: register ID
+* The return value: read register value
+*********************************************************************************************************
+*/
+uint8_t ADS1256::readReg(uint8_t _RegID)
+{
+ uint8_t readVal;
+
+ *cs = 0; /* SPI cs = 0 */
+ spi->write(CMD_RREG | _RegID); /* Write command register */
+ spi->write(0x00); /* Write the register number */
+
+
+ delayDATA(); /*delay time */
+
+ readVal = spi->write(0); /* Read the register values */
+ *cs =1; /* SPI cs = 1 */
+
+ return readVal;
+}
+
+/*
+*********************************************************************************************************
+* name: WriteCmd
+* function: Sending a single byte order
+* parameter: _cmd : command
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::writeCmd(uint8_t _cmd)
+{
+ *cs = 0; /* SPI cs = 0 */
+ spi->write(_cmd);
+ *cs =1; /* SPI cs = 1 */
+}
+
+/*
+*********************************************************************************************************
+* name: ReadChipID
+* function: Read the chip ID
+* parameter: _cmd : NULL
+* The return value: four high status register
+*********************************************************************************************************
+*/
+uint8_t ADS1256::readChipID(void)
+{
+ uint8_t id;
+
+ //waitDRDY();
+ id = readReg(REG_STATUS);
+ #ifdef DEBUG
+ pc.printf("id = %02x\r\n", id);
+ #endif
+ return (id >> 4);
+}
+
+/*
+*********************************************************************************************************
+* name: Setchannel
+* function: Configuration channel number
+* parameter: channel: channel number 0--7
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::setChannel()
+{
+ /*
+ Bits 7-4 PSEL3, PSEL2, PSEL1, PSEL0: Positive Input channel (AINP) Select
+ 0000 = AIN0 (default)
+ 0001 = AIN1
+ 0010 = AIN2 (ADS1256 only)
+ 0011 = AIN3 (ADS1256 only)
+ 0100 = AIN4 (ADS1256 only)
+ 0101 = AIN5 (ADS1256 only)
+ 0110 = AIN6 (ADS1256 only)
+ 0111 = AIN7 (ADS1256 only)
+ 1xxx = AINCOM (when PSEL3 = 1, PSEL2, PSEL1, PSEL0 are ¡°don¡¯t care¡±)
+
+ NOTE: When using an ADS1255 make sure to only select the available inputs.
+
+ Bits 3-0 NSEL3, NSEL2, NSEL1, NSEL0: Negative Input channel (AINN)Select
+ 0000 = AIN0
+ 0001 = AIN1 (default)
+ 0010 = AIN2 (ADS1256 only)
+ 0011 = AIN3 (ADS1256 only)
+ 0100 = AIN4 (ADS1256 only)
+ 0101 = AIN5 (ADS1256 only)
+ 0110 = AIN6 (ADS1256 only)
+ 0111 = AIN7 (ADS1256 only)
+ 1xxx = AINCOM (when NSEL3 = 1, NSEL2, NSEL1, NSEL0 are ¡°don¡¯t care¡±)
+ */
+ if( channel > 15 )
+ {
+ return;
+ }
+ writeReg(REG_MUX, (channel << 4) | (1<<3)); /* Bit3 = 1, AINN connection AINCOM */
+}
+
+/*
+*********************************************************************************************************
+* name: SetDiffchannel
+* function: The configuration difference channel
+* parameter: channel: channel number 0--3
+* The return value: four high status register
+*********************************************************************************************************
+*/
+void ADS1256::setDiffChannel()
+{
+ /*
+ Bits 7-4 PSEL3, PSEL2, PSEL1, PSEL0: Positive Input channel (AINP) Select
+ 0000 = AIN0 (default)
+ 0001 = AIN1
+ 0010 = AIN2 (ADS1256 only)
+ 0011 = AIN3 (ADS1256 only)
+ 0100 = AIN4 (ADS1256 only)
+ 0101 = AIN5 (ADS1256 only)
+ 0110 = AIN6 (ADS1256 only)
+ 0111 = AIN7 (ADS1256 only)
+ 1xxx = AINCOM (when PSEL3 = 1, PSEL2, PSEL1, PSEL0 are ¡°don¡¯t care¡±)
+
+ NOTE: When using an ADS1255 make sure to only select the available inputs.
+
+ Bits 3-0 NSEL3, NSEL2, NSEL1, NSEL0: Negative Input channel (AINN)Select
+ 0000 = AIN0
+ 0001 = AIN1 (default)
+ 0010 = AIN2 (ADS1256 only)
+ 0011 = AIN3 (ADS1256 only)
+ 0100 = AIN4 (ADS1256 only)
+ 0101 = AIN5 (ADS1256 only)
+ 0110 = AIN6 (ADS1256 only)
+ 0111 = AIN7 (ADS1256 only)
+ 1xxx = AINCOM (when NSEL3 = 1, NSEL2, NSEL1, NSEL0 are ¡°don¡¯t care¡±)
+ */
+
+ //use channel = 3 for strain gauge bridge
+ //use channel = 0 for Vout2
+ //use channel = 1 for Vout1
+
+ if (channel == 0)
+ {
+ writeReg(REG_MUX, (0 << 4) | 1); /* Diffchannel AIN0£¬ AIN1 */
+ }
+ else if (channel == 1)
+ {
+ writeReg(REG_MUX, (2 << 4) | 3); /*Diffchannel AIN2£¬ AIN3 */
+ }
+ else if (channel == 2)
+ {
+ writeReg(REG_MUX, (4 << 4) | 5); /*Diffchannel AIN4£¬ AIN5 */
+ }
+ else if (channel == 3)
+ {
+ writeReg(REG_MUX, (6 << 4) | 7); /*Diffchannel AIN6£¬ AIN7 */
+ }
+}
+
+/*
+*********************************************************************************************************
+* name: WaitDRDY
+* function: delay time wait for automatic calibration
+* parameter: NULL
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::waitDRDY(void)
+{
+ while ( nrdy->read() );
+}
+
+
+void ADS1256::getMaxWaitDelay_us(void)
+{
+ if(dataRate == 0x00)
+ {
+ maxWaitDelay_us = getDataRateVal_us(dataRate) + 8000;
+ }
+ else
+ {
+ maxWaitDelay_us = getDataRateVal_us(dataRate-1);
+ }
+}
+
+/*
+***********************`**********************************************************************************
+* name: ReadData
+* function: read ADC value
+* parameter: NULL
+* The return value: NULL
+*********************************************************************************************************
+*/
+int32_t ADS1256::readData(void)
+{
+ uint32_t readVal = 0;
+ static uint8_t buf[3];
+
+ *cs = 0; /* SPI cs = 0 */
+
+ spi->write(CMD_RDATA); /* read ADC command */
+
+ delayDATA(); /*delay time */
+
+ /*Read the sample results 24bit*/
+ buf[0] = spi->write(0);
+ buf[1] = spi->write(0);
+ buf[2] = spi->write(0);
+
+ readVal = ((uint32_t)buf[0] << 16) & 0x00FF0000;
+ readVal |= ((uint32_t)buf[1] << 8);
+ readVal |= buf[2];
+
+ *cs =1; //* CS = 1
+ /* Extend a signed number*/
+ if (readVal & 0x800000)
+ {
+ readVal |= 0xFF000000;
+ }
+
+ return (int32_t)readVal;
+}
+
+
+/*
+*********************************************************************************************************
+* name: ADS1256::GetAdc
+* function: read ADC value
+* parameter: channel number 0--7
+* The return value: ADC vaule (signed number)
+*********************************************************************************************************
+*/
+
+
+/*
+*********************************************************************************************************
+* name: ADS1256::ISR
+* function: Collection procedures
+* parameter: NULL
+* The return value: NULL
+*********************************************************************************************************
+*/
+void ADS1256::isr(void)
+{
+ if (scanMode == 0) /* 0 Single-ended input 8 channel, 1 Differential input 4 channels */
+ {
+ setChannel(); /*Switch channel mode */
+ wait_us(5);
+
+ writeCmd(CMD_SYNC);
+ wait_us(5);
+
+ writeCmd(CMD_WAKEUP);
+ wait_us(25);
+
+ if (channel == 0)
+ {
+ adcNow[7] = readData();
+ }
+ else
+ {
+ adcNow[channel-1] = readData();
+ }
+
+ if (++channel >= 8)
+ {
+ channel = 0;
+ }
+ }
+ else /*Diffchannel*/
+ {
+
+ setDiffChannel(); /* change Diffchannel */
+ wait_us(5);
+
+ writeCmd(CMD_SYNC);
+ wait_us(5);
+
+ writeCmd(CMD_WAKEUP);
+ wait_us(25);
+
+ if (channel == 0)
+ {
+ adcNow[3] = readData();
+ }
+ else
+ {
+ adcNow[channel-1] = readData();
+ }
+
+ if (++channel >= 4)
+ {
+ channel = 0;
+ }
+ }
+}
+
+/*
+*********************************************************************************************************
+* name: ADS1256::Scan
+* function:
+* parameter:NULL
+* The return value: 1
+*********************************************************************************************************
+*/
+uint8_t ADS1256::scan(void)
+{
+ if (!(cs->read()))
+ {
+ isr();
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+*********************************************************************************************************
+* name: Voltage_Convert
+* function: Voltage value conversion function
+* parameter: Vref : The reference voltage 3.3V or 5V
+* voltage : output DAC value
+* The return value: NULL
+*********************************************************************************************************
+*/
+uint16_t ADS1256::voltageConvert(float Vref, float voltage)
+{
+ uint16_t _D_;
+ _D_ = (uint16_t)(65536 * voltage / Vref);
+
+ return _D_;
+}
+
+void ADS1256::readDiffChannel(uint8_t nextChannel)
+{
+ waitDRDY();
+ prevChannel = channel;
+ channel = nextChannel;
+ if(channel != prevChannel)
+ {
+ setDiffChannel(); /*Switch channel mode to next channel to get it started*/
+ wait_us(5);
+
+ writeCmd(CMD_SYNC);
+ wait_us(5);
+
+ writeCmd(CMD_WAKEUP);
+ wait_us(25);
+ }
+ adcNow[prevChannel] = readData(); //get data from prev channel while new channel is integrating
+// pc.printf(" adcNow = %d\r\n", adcNow[prevChannel]);
+}
+
+uint32_t ADS1256::getDataRateVal_us(uint8_t dataRateIndex)
+{
+ static const uint32_t tabDataRateVal_us[16] =
+ {
+ 400000,
+ 200000,
+ 100000,
+ 66667,
+ 40000,
+ 33334,
+ 16667,
+ 16667,
+ 10000,
+ 2000,
+ 1000,
+ 500,
+ 267,
+ 134,
+ 34,
+ 7
+ /*reset the default values */
+ };
+ return tabDataRateVal_us[dataRateIndex];
+}
+
+void ADS1256::waitNDRDY(void)
+{
+ while(!nrdy->read());
+}
+
+void ADS1256::resync(void)
+{
+ waitDRDY();
+ wait_us(2);
+
+ writeCmd(CMD_SYNC);
+ wait_us(5);
+
+ writeCmd(CMD_WAKEUP);
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ADS1256.h Fri Dec 01 21:31:48 2017 +0000
@@ -0,0 +1,141 @@
+#ifndef __ADS1256_H__
+#define __ADS1256_H__
+
+#include "mbed.h"
+
+#define ADS1256_SPI_MODE 1
+#define DRATE_MAX 16
+#define DEBUG
+
+#define ADS1256_GAIN_1 0 /* GAIN 1 */
+#define ADS1256_GAIN_2 1 /*GAIN 2 */
+#define ADS1256_GAIN_4 2 /*GAIN 4 */
+#define ADS1256_GAIN_8 3 /*GAIN 8 */
+#define ADS1256_GAIN_16 4 /* GAIN 16 */
+#define ADS1256_GAIN_32 5 /*GAIN 32 */
+#define ADS1256_GAIN_64 6 /*GAIN 64 */
+
+
+#define ADS1256_30000SPS 15
+#define ADS1256_15000SPS 14
+#define ADS1256_7500SPS 13
+#define ADS1256_3750SPS 12
+#define ADS1256_2000SPS 11
+#define ADS1256_1000SPS 10
+#define ADS1256_500SPS 9
+#define ADS1256_100SPS 8
+#define ADS1256_60SPS 7
+#define ADS1256_50SPS 6
+#define ADS1256_30SPS 5
+#define ADS1256_25SPS 4
+#define ADS1256_15SPS 3
+#define ADS1256_10SPS 2
+#define ADS1256_5SPS 1
+#define ADS1256_2d5SPS 0
+
+
+class ADS1256
+{
+ SPI *spi;
+ DigitalOut *cs;
+ DigitalIn *nrdy;
+
+ public:
+ ADS1256(SPI *, DigitalIn *, DigitalOut *);
+ uint8_t gain;
+ uint8_t dataRate;
+ int32_t adcNow[8]; /* ADC Conversion value */
+ uint8_t channel; /* The current channel*/
+ uint8_t prevChannel; /* The previous channel --when muxing */
+ uint8_t scanMode; /*Scanning mode, 0 = Single-ended input 8 channel; 1= Differential input 4 channels*/
+ uint8_t buffer_en;
+ uint32_t maxWaitDelay_us;
+ /* gain channelî */
+
+
+ /* Sampling speed choice*/
+ /*
+ 11110000 = 30,000SPS (default)
+ 11100000 = 15,000SPS
+ 11010000 = 7,500SPS
+ 11000000 = 3,750SPS
+ 10110000 = 2,000SPS
+ 10100001 = 1,000SPS
+ 10010010 = 500SPS
+ 10000010 = 100SPS
+ 01110010 = 60SPS
+ 01100011 = 50SPS
+ 01010011 = 30SPS
+ 01000011 = 25SPS
+ 00110011 = 15SPS
+ 00100011 = 10SPS
+ 00010011 = 5SPS
+ 00000011 = 2.5SPS
+ */
+
+
+ /*Register definitions Table 23. Register Map --- ADS1256 datasheet Page 30*/
+ enum
+ {
+ /*Register address, followed by reset the default values */
+ REG_STATUS = 0, // x1H
+ REG_MUX = 1, // 01H
+ REG_ADCON = 2, // 20H
+ REG_DRATE = 3, // F0H
+ REG_IO = 4, // E0H
+ REG_OFC0 = 5, // xxH
+ REG_OFC1 = 6, // xxH
+ REG_OFC2 = 7, // xxH
+ REG_FSC0 = 8, // xxH
+ REG_FSC1 = 9, // xxH
+ REG_FSC2 = 10, // xxH
+ };
+
+ /* Command definition£º TTable 24. Command Definitions --- ADS1256 datasheet Page 34 */
+ enum
+ {
+ CMD_WAKEUP = 0x00, // Completes SYNC and Exits Standby Mode 0000 0000 (00h)
+ CMD_RDATA = 0x01, // Read Data 0000 0001 (01h)
+ CMD_RDATAC = 0x03, // Read Data Continuously 0000 0011 (03h)
+ CMD_SDATAC = 0x0F, // Stop Read Data Continuously 0000 1111 (0Fh)
+ CMD_RREG = 0x10, // Read from REG rrr 0001 rrrr (1xh)
+ CMD_WREG = 0x50, // Write to REG rrr 0101 rrrr (5xh)
+ CMD_SELFCAL = 0xF0, // Offset and Gain Self-Calibration 1111 0000 (F0h)
+ CMD_SELFOCAL= 0xF1, // Offset Self-Calibration 1111 0001 (F1h)
+ CMD_SELFGCAL= 0xF2, // Gain Self-Calibration 1111 0010 (F2h)
+ CMD_SYSOCAL = 0xF3, // System Offset Calibration 1111 0011 (F3h)
+ CMD_SYSGCAL = 0xF4, // System Gain Calibration 1111 0100 (F4h)
+ CMD_SYNC = 0xFC, // Synchronize the A/D Conversion 1111 1100 (FCh)
+ CMD_STANDBY = 0xFD, // Begin Standby Mode 1111 1101 (FDh)
+ CMD_RESET = 0xFE, // Reset to Power-Up Values 1111 1110 (FEh)
+ };
+
+
+
+
+
+ //declare functions
+ void setSpi(void);
+ void cfgADC(void);
+ void delayDATA(void);
+ void writeReg(uint8_t _RegID, uint8_t _RegValue);
+ uint8_t readReg(uint8_t _RegID);
+ void writeCmd(uint8_t _cmd);
+ uint8_t readChipID(void);
+ void setChannel();
+ void setDiffChannel();
+ void waitDRDY(void);
+ void waitNDRDY(void);
+ int32_t readData(void);
+ uint8_t getGainVal(void);
+ void isr(void);
+ uint8_t scan(void);
+ uint16_t voltageConvert(float Vref, float voltage);
+ void readDiffChannel(uint8_t);
+ uint32_t getDataRateVal_us(uint8_t);
+ void getMaxWaitDelay_us(void);
+ void resync(void);
+
+};
+
+#endif
\ No newline at end of file