ADS1259 Read Data Continuous Mode

I see that the ADS1299 data sheet (with similar interface) in the Command Definitions table says: 

Enable Read Data Continuous mode. RDATAC 0001 0000 (10h) This mode is the default mode at power-up.(1)

(1) When in RDATAC mode, the RREG command is ignored.

Are these things also true of the ADS1259?

If so, does that mean I can do a WREG transfer while in Read Data Continuous mode?

Or do I need to issue a SDATAC command first?

I'll take note of that. Thank you for sharing!

Best regards,
Chris

HI Emmett,

Do you have a code to share how do you send and read data to/from ADS1259 ?

Regards, David

Hi David,

We are communicating through custom IP in our FPGA, so our code wouldn't apply to other platforms.

Here is the flow we are using:

Initialize ADS1259 ADC

1.     Disable any related interrupts

2.     Reset ADC with reset pin, keep Start pin low

3.     Set SCLK_PHASE=1, SCLK_POLARITY=0, XFER_SIZE=0 =32 bits

4.     SPI Transfer 0x11 in SPI_TXD (31:24) to command Stop Read Data Continuous mode

5.     SPI Transfer WREG command to enable internal reference and set conversion mode and rate

SPI_TXD = 0x41011000 10 Hz Continuous

SPI_TXD = 0x41011010 for 10Hz pulsed

SPI_TXD = 0x41011017 for 14.4kHz pulsed (used for Lock-In)

6.     SPI Transfer 0x10 in SPI_TXD (31:24) to command Read Data Continuous mode

7.     SPI_TXD = 0x00000000

Set up and get continuous (gated) ADC Results

1.     Initialize ADC for non-pulsed (0x41011000)

2.     Enable interrupt on falling edge of DRDY

3.     Set Start pin high

4.     Wait for DRDY Interrupt

5.     Perform SPI transfer

6.     Repeat 4-5 for subsequent readings

Note: ADC conversions continue until power down or ADC_RST or ADC_STZ

Setup and get single-triggered (pulsed) ADC Results - Mode 2

1.     Initialize ADC for pulsed (0x41011010)

2.     Enable interrupt on falling edge of DRDY

3.     Pulse Start pin

4.     Wait for DRDY Interrupt

5.     Perform SPI transfer

6.     Repeat 3-5 for subsequent readings

Pause Conversions

1.     Pull the Start pin low

What is the meaning of this?:

SPI_TXD = 0x41011000 10 Hz Continuous

SPI_TXD = 0x41011010 for 10Hz pulsed

SPI_TXD = 0x41011017 for 14.4kHz pulsed (used for Lock-In)

Hi David,

Those are  SPI commands sent to the ADC to write to the CONFIG1 and CONFIG2 resigsters. See table 19 and table 20 in the data sheet.

Regards,
Chris

Hi Christopher,

Thank you.

I want to start single conversion in pulse mode, and when I started the OPCODE for START I preform task like in datasheet Figure 52. Pulse Control Mode,

and DRDY goes low when data is rdy and triggers an interrupt on pin P1.2 and in the interrupt routine is sending RDATA OPCODE to read data MSB MID LSB and i get for inputs tied low MSB=FF MID=FF LSB=9F i thin it should be all MSB=0x00 MID=0x00 LSB= something small what is the problem?

MY code:

// Description: Toggle P1.0 by xor'ing P1.0 inside of a software loop.
// ACLK = 32.768kHz, MCLK = SMCLK = default DCO~1MHz

//******************************************************************************
#include <msp430.h>
#include "gpio.h"
#include "inc/hw_memmap.h"
#include "usci_a_spi.h"
#include "ucs.h"
#include "wdt_a.h"

uint8_t transmitData = 0x00, receiveData1 = 0x00, receiveData2 = 0x00, receiveData3 = 0x00, junk = 0x00, DMSB = 0x00, DMID = 0x00, DLSB =0x00;

int main(void)
{
volatile unsigned int i;

WDTCTL = WDTPW+WDTHOLD; // Stop WDT

GPIO_setAsOutputPin(
GPIO_PORT_P1,
GPIO_PIN3
); // START as output

P4DIR |= 0x08; // Set P4.3 to output direction
P4SEL |= BIT0+BIT4+BIT5; // P4.0,4,5 option select

GPIO_setAsInputPin(GPIO_PORT_P1, //DRDY inpit for interupt
GPIO_PIN2);

// interuprt DRDY on pin P1.2
P1IES |= BIT2; // high -> low is selected with IES.x = 1.
P1IFG &= ~BIT2; // To prevent an immediate interrupt, clear the flag for
// P1.2 before enabling the interrupt.
P1IE |= BIT2; // Enable interrupts for P1.2
_enable_interrupt();

GPIO_setOutputHighOnPin( //CS high
GPIO_PORT_P4,
GPIO_PIN3
);
GPIO_setOutputLowOnPin( //START low
GPIO_PORT_P1,
GPIO_PIN3
);

UCA1CTL1 |= UCSWRST; // **Put state machine in reset**
UCA1CTL0 |= UCMST+UCSYNC+UCMSB; // 3-pin, 8-bit SPI master,Clock polarity low, MSB

UCA1CTL1 |= UCSSEL_2; // SMCLK
UCA1BR0 = 0x02; // /2
UCA1BR1 = 0; //
UCA1MCTL = 0; // No modulation
UCA1CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
//UCA1IE |= UCRXIE; // Enable USCI_A0 RX interrupt

P4OUT &= ~0x08; //CS low
for(i=50000;i>0;i--);

// Reset to power-up values RESET

transmitData = 0x06;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
//TransmitData
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

for(i=50000;i>0;i--);
GPIO_setOutputHighOnPin(GPIO_PORT_P4,
GPIO_PIN3);
P4OUT &= ~0x08;
for(i=50000;i>0;i--);

// Stop Read Data Continuous mode SDATAC

transmitData = 0x11;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
//TransmitData
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

for(i=50000;i>0;i--);
GPIO_setOutputHighOnPin(GPIO_PORT_P4,
GPIO_PIN3);
P4OUT &= ~0x08;
for(i=50000;i>0;i--);

// Write register CONFIG0,1,2 at address 0h,1h,2h

transmitData = 0x40;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0x02;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0x01;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0x08;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0x10;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

for(i=50000;i>0;i--);
GPIO_setOutputHighOnPin(GPIO_PORT_P4,
GPIO_PIN3);
P4OUT &= ~0x08;
for(i=50000;i>0;i--);

//Read register CONFIG0,1,2 at address 0h,1h,2h

transmitData = 0x20;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0x02;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0xFF; //dummy for clk
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);
junk = USCI_A_SPI_receiveData(USCI_A1_BASE);

receiveData1 = USCI_A_SPI_receiveData(USCI_A1_BASE);

//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);
junk = USCI_A_SPI_receiveData(USCI_A1_BASE);

receiveData2 = USCI_A_SPI_receiveData(USCI_A1_BASE);

//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);
junk = USCI_A_SPI_receiveData(USCI_A1_BASE);

receiveData3 = USCI_A_SPI_receiveData(USCI_A1_BASE);

for(i=50000;i>0;i--);
GPIO_setOutputHighOnPin(GPIO_PORT_P4,
GPIO_PIN3);
P4OUT &= ~0x08;
for(i=50000;i>0;i--);

// Read data

// START conversion

transmitData = 0x08;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
//TransmitData
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

while(1){};

}

#pragma vector = PORT1_VECTOR
__interrupt void P1_ISR(void) {
switch(P1IFG & BIT2) {
case BIT2:
P1IFG &= ~BIT2; // clear the interrupt flag

//Read data by opcode RDATA
transmitData = 0x12;
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
//TransmitData
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);

transmitData = 0x00; //dummy for clk
//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);
junk = USCI_A_SPI_receiveData(USCI_A1_BASE);

DMSB = USCI_A_SPI_receiveData(USCI_A1_BASE);

//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);
junk = USCI_A_SPI_receiveData(USCI_A1_BASE);

DMID = USCI_A_SPI_receiveData(USCI_A1_BASE);

//USCI_A0 TX buffer ready?
while (!USCI_A_SPI_getInterruptStatus(USCI_A1_BASE,
USCI_A_SPI_TRANSMIT_INTERRUPT)) ;
USCI_A_SPI_transmitData(USCI_A1_BASE, transmitData);
junk = USCI_A_SPI_receiveData(USCI_A1_BASE);

DLSB = USCI_A_SPI_receiveData(USCI_A1_BASE);

return;
default:
P1IFG = 0; // probably unnecessary, but if another flag occurs
// in P1, this will clear it. No error handling is
// provided this way, though.
return;
}
} // P1_ISR

Regards David.

Hi David,

If you're observing the correct SPI operations on the oscilloscope, you're probably reading the correct value.
0xFFFF9F is a small negative number. This would correspond to -28.9uV (using the 2.5V reference).

Regards,
Chris