Can't read ADS1293's registers with Tiva-C at once. I can read it after 8 times.

Burak Dogan

Other Parts Discussed in Thread: MSP430F5529, ADS1293

Hi all,

I disconnect MSP430F5529 on ADS1293 by scratching R25, R26 and R28 on board and I am driving J2 (SPI) port with Tiva-C LaunchPad.

My first problem is; I can't read the register at once. When I want to read specific address, I have to read in "for" loop. (after 8 times, in 9th count)

My code is attached. I would appreciate if you can help.

Best Regards,

Burak

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/sysctl.h"
#include "driverlib/interrupt.h"
#include "driverlib/gpio.h"
#include "driverlib/timer.h"

// SPI
#include "inc/hw_ssi.h"
#include "driverlib/ssi.h"
#include "driverlib/pin_map.h"

void ClockSetup(void);
void SetupSPI(void);
void ADS1293_RegWrite(uint32_t adres,uint32_t value);
uint32_t ADS1293_RegRead(uint32_t adres2);
void ADS1293_Setup_3Lead(void);


uint32_t read_value;
uint32_t value;
uint32_t value2;

uint32_t inst1;
uint32_t inst2;

int i;


#define ADS1293_WRITE_BIT                             (0x7F)
#define ADS1293_READ_BIT                              (0x80)


void ClockSetup(void){

	SysCtlClockSet(SYSCTL_SYSDIV_5|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);

}

void SetupSPI(void){

	SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI3);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

	GPIOPinConfigure(GPIO_PD0_SSI3CLK);
	GPIOPinConfigure(GPIO_PD3_SSI3TX);
        GPIOPinConfigure(GPIO_PD2_SSI3RX);
        GPIOPinTypeSSI(GPIO_PORTD_BASE,GPIO_PIN_3|GPIO_PIN_0|GPIO_PIN_2);

        SSIConfigSetExpClk(SSI3_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_0, SSI_MODE_MASTER, 16000000, 16);
        SSIEnable(SSI3_BASE);

        GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, GPIO_PIN_1);
        GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_1, GPIO_PIN_1);

}

int main(void)
{


	ClockSetup();
	SetupSPI();
	ADS1293_Setup_3Lead();
	
	for(i=0;i<9;i++){                                                 //replace 9 with 1 it doesn't work 
		value2=ADS1293_RegRead(0x01);   //reading 0x01 for example
		value2&=0x00FF;
	}



	}
}


void ADS1293_RegWrite(uint32_t adres,uint32_t value)
{
	GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_1, 0);

	inst1 = ((ADS1293_WRITE_BIT & adres)<<8)|value;

	SSIDataPut(SSI3_BASE,inst1);
	while(SSIBusy(SSI3_BASE));

	GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_1, GPIO_PIN_1);
}

uint32_t ADS1293_RegRead(uint32_t adres2)
{
	GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_1, 0);

	inst2 = (ADS1293_READ_BIT | adres2)<<8;

	SSIDataPut(SSI3_BASE,inst2);
	while(SSIBusy(SSI3_BASE));

	SSIDataGet(SSI3_BASE, &read_value);
	while(SSIBusy(SSI3_BASE));

	GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_1, GPIO_PIN_1);
	return read_value;
}


void ADS1293_Setup_3Lead(void)
{
	ADS1293_RegWrite(0x00,0x00);
	ADS1293_RegWrite(0x01,0x11);
	ADS1293_RegWrite(0x02,0x19);
	ADS1293_RegWrite(0x0A,0x07);
	ADS1293_RegWrite(0x0C,0x04);
	ADS1293_RegWrite(0x12,0x04);
	ADS1293_RegWrite(0x14,0x24);
	ADS1293_RegWrite(0x21,0x02);
	ADS1293_RegWrite(0x22,0x02);
	ADS1293_RegWrite(0x23,0x02);
	ADS1293_RegWrite(0x27,0x08);
	ADS1293_RegWrite(0x2F,0x30);
}

over 9 years ago

0 Vishy Viswanathan over 9 years ago

TI__Mastermind 21685 points

Burak,

Comparing with the sample MSP430 code for ADS1293 (see links below), it looks to me you have to use Moto_Mode_1 for Tiva's SSI in the SSIConfigSetExpClk call. That's when phase is high. If I see anything else, will let you know.

http://www.ti.com/lit/pdf/snaa211

http://www.ti.com/lit/zip/snac054

Thanks, Vishy

0 Vishy Viswanathan over 9 years ago in reply to Vishy Viswanathan

TI__Mastermind 21685 points

Looking at Tiva examples, I think you might also need a SSIClockSourceSet call before SSIConfigSetExpClk. Please also check ADS1293 SPI Clock does not exceed 20MHz. thanks, Vishy

0 Burak Dogan over 9 years ago in reply to Vishy Viswanathan

Prodigy 50 points

Thanks Vishy but it did not work. Code is only working with moto_mode_0.

0 Burak Dogan over 9 years ago in reply to Vishy Viswanathan

Prodigy 50 points

And calling SSIClockSourceSet does not make any difference. Thanks.

0 Vishy Viswanathan over 9 years ago in reply to Burak Dogan

TI__Mastermind 21685 points

Could you share scope shots of the SPI signals during a read. Also, share with us your schematic.

The code seems to use GPIO_PIN_1 as a chip select. Instead you have to configure and use the Frame select signal. DS shows SSIFss functioning as the chip select.

In code, I see only three signals configured

GPIOPinTypeSSI(GPIO_PORTD_BASE,GPIO_PIN_3|GPIO_PIN_0|GPIO_PIN_2);

and I am guessing the Fss signal is missing. Please check..

0 Burak Dogan over 9 years ago in reply to Vishy Viswanathan

Prodigy 50 points

Hi Vishy,

I separate chip select on purpose because CS change its condition (low / high) automatically. I lose data because of this situation. I am controlling CS myself with GPIOPinWrite during my operations.

I will share scope shots and my schematic.

Thanks.

0 Vishy Viswanathan over 9 years ago in reply to Burak Dogan

TI__Mastermind 21685 points

Please check in Tiva forum if your approach (using GPIO instead of Fss) is correct. I don't see a reason why you would lose data otherwise. Thanks, Vishy

Data converters

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Can't read ADS1293's registers with Tiva-C at once. I can read it after 8 times.