SPI communication between two F28069 Control Sticks

Hi Sneha,

I initially started with CAN but it is not possible with the control sticks and i have only three days left to establish communication between two control sticks.

Yup got to know that. I thought as you're planning to use eCAN you might be having the transceivers ready :)

I wish to send data through SPI of one DSP to SPI of another DSP n if possible display it on the terminal.

No problem, here's its much simpler: you can directly connect the SPISOMI, SPISIMO, SPICLK and SPISTEA lines to accordingly. For eg.

Refer spi_loopback or spi_loopback_interrupts examples for quick implementations as times running! They can be found here:

C:\ti\controlSUITE\device_support\f2806x\v136\F2806x_examples_ccsv5\spi_loopback

Regards,

Gautam

Hi Sneha,

I initially started with CAN but it is not possible with the control sticks and i have only three days left to establish communication between two control sticks.

Yup got to know that. I thought as you're planning to use eCAN you might be having the transceivers ready :)

I wish to send data through SPI of one DSP to SPI of another DSP n if possible display it on the terminal.

No problem, here's its much simpler: you can directly connect the SPISOMI, SPISIMO, SPICLK and SPISTEA lines to accordingly. For eg.

Refer spi_loopback or spi_loopback_interrupts examples for quick implementations as times running! They can be found here:

C:\ti\controlSUITE\device_support\f2806x\v136\F2806x_examples_ccsv5\spi_loopback

Regards,

Gautam

Thank you Gautam..

I am going through the given examples only...

Hi

I have gone through the example codes.Now as per my understanding for communication between two control sticks:

1.In SPICCR to keep the SPIBLK=0 i.e loopback disabled.

2. In SPICTL changing bit 2 to 0/1 for slave/master dsps respectively.

3. No use of SPI-B only using SPI-A in both DSPs with GPIO pins 16,17,18,19

4. Enabling the transmission part in Master Dsp and recieving part in Slave DSPs.

Please correct me if I am wrong.I have made the respective changes in programs for master/slave dsp's and got no error while debugging.

Now should i proceed with their connections?

How can we get a data transmitted such that it can be displayed on the terminal by slave DSP.

Thank you

Now should i proceed with their connections?

How can we get a data transmitted such that it can be displayed on the terminal by slave DSP.

Yup, do proceed. You can check out the transmit and receive data registers of SPIA peripheral in Global variables (watch windows during debug session). No need to display the same on hyperterminal for now.

Regards,

Gautam

oki

thanks

Hi Gautam

I tried doing the implementation.The conncetions done were:

Header pin 20(Master) to Pin 20(Slave),i.e SPISOMIA

Header pin 24(Master) to Pin 24(Slave),i.e SPISIMOA

Header pin 25(Master) to Pin 25(Slave),i.e SPISTEA

Header pin 29(Master) to Pin 29(Slave),i.e SPICLKA

But as i m running the program for master its haults in between and do not recognize sdata/rdata...... and for slave it shows changes only in sdata.

The register values for spia registers are also not same..

MASTER-

#include "DSP28x_Project.h" // Device Headerfile and Examples Include File

// Prototype statements for functions found within this file.
// interrupt void ISRTimer2(void);
void delay_loop(void);
void spi_xmit(Uint16 a);
void spi_fifo_init(void);
void spi_init(void);
void error(void);

void main(void)
{
Uint16 sdata; // send data
Uint16 rdata; // received data

InitSysCtrl();

InitSpiaGpio();

DINT;

InitPieCtrl();

// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;


InitPieVectTable();


spi_fifo_init(); // Initialize the Spi FIFO
spi_init(); // init SPI

sdata = 0x0000;
for(;;)
{
// Transmit data
spi_xmit(sdata);
// Wait until data is received
while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }
// Check against sent data
rdata = SpiaRegs.SPIRXBUF;
if(rdata != sdata) error();
sdata++;
}
}

// Step 7. Insert all local Interrupt Service Routines (ISRs) and functions here:

void delay_loop()
{
long i;
for (i = 0; i < 1000000; i++) {}
}

void error(void)
{
asm(" ESTOP0"); // Test failed!! Stop!
for (;;);
}

void spi_init()
{
SpiaRegs.SPICCR.all =0x000F; // Reset on, rising edge, 16-bit char bits,loopback disabled
SpiaRegs.SPICTL.all =0x0006; // Enable master mode, normal phase,
// enable talk, and SPI int disabled.
SpiaRegs.SPIBRR =0x007F;
SpiaRegs.SPICCR.all =0x008F; // Relinquish SPI from Reset
SpiaRegs.SPIPRI.bit.FREE = 1; // Set so breakpoints don't disturb xmission
}

void spi_xmit(Uint16 a)
{
SpiaRegs.SPITXBUF=a;
}

void spi_fifo_init()
{
// Initialize SPI FIFO registers
SpiaRegs.SPIFFTX.all=0xE040;
// SpiaRegs.SPIFFRX.all=0x2044;
SpiaRegs.SPIFFCT.all=0x0;
}

SLAVE

#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File

// Prototype statements for functions found within this file.
// interrupt void ISRTimer2(void);
void delay_loop(void);
//void spi_xmit(Uint16 a);
void spi_fifo_init(void);
void spi_init(void);
void error(void);

void main(void)
{
  Uint16 sdata;  // send data
   Uint16 rdata;  // received data
   

   InitSysCtrl();

   InitSpiaGpio();


   DINT;


   InitPieCtrl();

// Disable CPU interrupts and clear all CPU interrupt flags:
   IER = 0x0000;
   IFR = 0x0000;
   

   InitPieVectTable();
    

   spi_fifo_init();      // Initialize the Spi FIFO
   spi_init();          // init SPI

// Step 5. User specific code:
// Interrupts are not used in this example. 
   sdata = 0x0000;                            
   for(;;)
   {    
     // Transmit data
  //   spi_xmit(sdata);
     // Wait until data is received
     while(SpiaRegs.SPIFFRX.bit.RXFFST !=1) { }             
     // Check against sent data
     rdata = SpiaRegs.SPIRXBUF;                
     if(rdata != sdata) error();
     sdata++;
   }
}     

// Step 7. Insert all local Interrupt Service Routines (ISRs) and functions here:    

void delay_loop()
{
    long      i;
    for (i = 0; i < 1000000; i++) {}
}

void error(void)
{
    asm("     ESTOP0");                        // Test failed!! Stop!
    for (;;);
}

void spi_init()
{    
    SpiaRegs.SPICCR.all =0x000F;                 // Reset on, rising edge, 16-bit char bits  
    SpiaRegs.SPICTL.all =0x0002;                 // Enable master mode, normal phase,
                                                 // enable talk, and SPI int disabled.
    SpiaRegs.SPIBRR =0x007F;                                    
    SpiaRegs.SPICCR.all =0x00F;                 // Relinquish SPI from Reset   
    SpiaRegs.SPIPRI.bit.FREE = 1;                // Set so breakpoints don't disturb xmission
}

//void spi_xmit(Uint16 a)
//{
//    SpiaRegs.SPITXBUF=a;
//}    

void spi_fifo_init()                                        
{
// Initialize SPI FIFO registers
 //   SpiaRegs.SPIFFTX.all=0xE040;
    SpiaRegs.SPIFFRX.all=0x2044;
    SpiaRegs.SPIFFCT.all=0x0;
}  

Hi

After checking the signals on DSO for master i am getting output for clock only and negative voltage for MOSI and positive for MISO..

when i check out the watch varibales

rdata= identifier not found

sdata=once it will be 0 and some other time it would be identifier not found..

Kindly help.

HI Gautam

I am trying to that SPI interface for two f28069 control sticks..I changed the SPICCR to loopback disabled and SPICTL 1/0 for master and slave dsp's.
But I am not getting anything when i check the watch variable for sdata it is zero at times and at times identifier is not found..while rdata has some value...
So,am not sure whether this is true or not?

when is check the spi_loopback example on DSO and make the changes in it for loopback disabled mode,it does nt give the required waveforms..Actaully changing any of the bits of SPICCR results in this..

Kindly reply ,I am stuck here for last two days.

thanks

Sneha, sorry for the late reply. I would like you to check this pdf:

http://academic.cankaya.edu.tr/~yuriy/Lessons/Module7.pdf

Regards,

Gautam

Hi

I have gone through the pdf and the required changes have already been implemented and I am still facing the issues.see the attached screenshots

1

this one is for master...sdata..rdata not recognised...

SpiaRegs.SPICCR.all =0x000F; // Reset on, rising edge, 5-bit char bits,loopback disabled
SpiaRegs.SPICTL.all =0x0006; // Enable master mode, normal phase,
// enable talk, and SPI int disabled.
SpiaRegs.SPIBRR =0x007F;
SpiaRegs.SPICCR.all =0x008F; // Relinquish SPI from Reset
SpiaRegs.SPIPRI.bit.FREE = 1; // Set so breakpoints don't disturb xmission
}

and for slave:

HI

I have again checked up the Pdf.

1. In the Pdf SPICCR.4= reserved while in datasheet i.e SPRU18 SPICCR.4= SPILBK...which one is correct?

2. The program works only when SPILBK is enabled..But as I am communicating between two control sticks,shouldn't it be disabled?

3. Is it required to set SPIDAT,SPISTS register in the program or is it automatically taken?

I am working on SPI_loopback without interrupt.

thank you

Hi,

1. In the Pdf SPICCR.4= reserved while in datasheet i.e SPRU18 SPICCR.4= SPILBK...which one is correct?

Refer only SPRU18D for configurations, the pdf that I've attached above is a generic one and is only for reference.

2. The program works only when SPILBK is enabled..But as I am communicating between two control sticks,shouldn't it be disabled?

You've to disable this mode for communication between 2 controlSticks ie SPILBK = 0;

3. Is it required to set SPIDAT,SPISTS register in the program or is it automatically taken?

SPIDAT is the register where the data is loaded and you don't have to worry about that it will be taken care by the library. As for SPISTS, here's an example:

Uint16 data;
Uint16 dummy;
SpiaRegs.SPICTL.bit.TALK = 1;                                            // Enable Transmit path
SpiaRegs.SPITXBUF = data;                                                 // Master transmits data
while(SpiaRegs.SPISTS.bit.INT_FLAG !=1) {}                    // Waits until data rx’d
dummy = SpiaRegs.SPIRXBUF;                                          // Clears junk data from itself
                                                                                                    // bc it rx’d same data tx’d

Regards,

Gautam

Hi

Thanks Gautam . It solved my previous problem.

Now when I test the slave or even when i connect both the control sticks, Send data bit i.e. sdata is always zero,recieve data bit i.e. rdata changes but gets fixed at a certain number and does not change afterwards...

Gautam,

the website you refered to is not authorized to publish that material. The officlal material, including the SPI - chapter can be found and downloaded here:

http://e2e.ti.com/group/universityprogram/educators/w/wiki/2037.teaching-roms.aspx

and especially for C2000: http://e2e.ti.com/group/universityprogram/educators/w/wiki/2038.c2000-teaching-rom.aspx

I'll sent a note to TI Legal department.

Frank said:

the website you refered to is not authorized to publish that material. The officlal material, including the SPI - chapter can be found and downloaded here:

Oh! is that so; a google search led me to that link.

I'll sent a note to TI Legal department.

Sure sure, please do so. Thanks for the information.

Regards,

Gautam

Hi gautam

the example you gave me is for 3-wire master transmit mode. So even if i write this to one and 3-wire slave recieve into other dsp, rdata is not equal to sdata, nor the data of two DSPs match.

In 3-wire mode, the receive and transmit paths within the SPI are connected, any data
transmitted by the SPI module is also received by itself and i want to communicate between two DSPs using 4-wire mode.

The problem I am facing is the time i disable the loopback in SPICCR the identifiers sdata and rdata are not recognised...i have earlier sent you the screenshots..

please help me.

Hi

Kindly help me with the doubts posted earlier..

gautam/frank

can u please advise how to move ahead with f28069 control stick now?? Hoping that spi communication would be established soon..I want to use f28069 control stick/card for communication purposes between two sources within a microgrid in future.

thank you

No problem. I guess Maria has already replied. Try to implement her suggestion and let us know how it goes.

Regards,

Gautam