Actions
Forum Thread Details
  • State Not Answered
  • Replies 7 replies
  • Subscribers 175 subscribers
  • Views 305 views
  • Users 0 members are here
Related

Error running PS SPI through PMOD - any help appreciated

Former Member

Hello,

Are you able to help me alittle bit with my SPI? I am facing alot of trouble with it.
I directed my SPI1 to PMOD, then got some code running. I am connecting a 8 bit shift register to the PMOD and im sending 1 byte and reading 2 bytes - which means that every data the data i send, must be received back on the 2nd location of the buffer.

This WORKS - but only sometimes.! i run the code, and it returns without any errors, but when i run it again, it gets stuck in the XSpiPs_PolledTransfer command, and im not sure why.. attached in the function.

I will really appreciate it if you could take a look at it!!!

Thank you in advance..



#define DS26518_SPI_SELECTt0x01

/**
int SpiPsreadIDR(u16 DeviceId)
{
tint Status;
tu8 writeBuffer2[2];
tu8 readBuffer2[2];

treadBuffer2[0]=0x00;
treadBuffer2[1]=0x00;
treadBuffer2[2]=0x00;
twriteBuffer2[0]=0xBF;
twriteBuffer2[1]=0xAA;

txil_printf("Initializing config
r");
tXSpiPs_Config *SpiConfig;

tSpiConfig = XSpiPs_LookupConfig(DeviceId);
tif (NULL == SpiConfig) {
ttreturn XST_FAILURE;
t}
tStatus = XSpiPs_CfgInitialize(&Spi, SpiConfig, SpiConfig->BaseAddress);
tif (Status != XST_SUCCESS) {
ttreturn XST_FAILURE;
t}

tXSpiPs_SetOptions(&Spi, XSPIPS_MASTER_OPTION |
ttt   XSPIPS_FORCE_SSELECT_OPTION);

tXSpiPs_SetClkPrescaler(&Spi, XSPIPS_CLK_PRESCALE_64);
tXSpiPs_SetSlaveSelect(&Spi, DS26518_SPI_SELECT);

tXSpiPs_PolledTransfer(&Spi,writeBuffer2,readBuffer2,2);

txil_printf("IDR value is: MSB: %x
r", writeBuffer2[0]);
txil_printf("IDR value is: LSB: %x
r", writeBuffer2[1]);
txil_printf("IDR value is: MSB: %x
r", readBuffer2[0]);
txil_printf("IDR value is: MSB: %x
r", readBuffer2[1]);

treturn XST_SUCCESS;
}

  • 0

    Hi Joe,

    I've seen this with several of the library routines. A power cycle of the board between runs usually fixes it. Otherwise, you end up debugging the library routines. Been there, not fun.

    Good luck,
    Mike

  • 0 in reply to Former Member

    yeah not fun at all!
    However, even when i power off the board then power it on again, sometimes it still doesnt work!

    Thank you Mike for the help. Where can i find the 14.6 libraries?

  • 0

    You have to have installed ISE 14.6.
    In the XSDK select the "Xilinx Tools" menu.
    Select "Repositories".
    Under "SDK Installation Repositories" you will see where on your system the libraries for the current version are stored.

    On mine, I change 14.4 to 14.6 to access the path for the latest libraries.

    Mine are at,
    C:Xilinx14.6ISE_DSEDKswXilinxProcessorIPLibdriversspips_v1_05_asrc

    Adding the 14.6 repositories should load the latest drivers into your build.

  • 0

    Hi Mike,

    Thank you, i will update my tools or/and update and move in to the newer library.
    i will let you know what happens by then (hopefully tomorrow or the day after).

    So far it seems that the TX fifo is becoming full but its not sending data as the SPI controller wont innitiate SCLK. Does this problem sound familiar to you in any way?

  • 0

    I remember I ran into a device that was active high instead of active low. It seems to me that it had similar symptoms. If your device is active low then ignore the rest of this comment.

    Since I was using EMIO, I just inverted the select bit on the way to the device. With MIO it's a more difficult problem.

    0x0E might work to deassert the device.
    0x0F might work to assert the device.

    However, XSpiPs_SetSlaveSelect() will not accept these values. You'll have to write the register yourself in the same way as the routine itself.

  • 0

    Hi Mike, you were right all along.
    Apparently the problem was the tools version/ library/drivers version that i was using.

    I upgraded my tools to 14.6 (from 14.2) and used the same code even - everything works without any problems.

    The only issue with the SPI is the SS0 (chip select 0). When directing the SPI1 to PS PMOD (MIO), SS0 will not work! and it will hang your SPI prepherial. You must instead use SS1 and SS2. or use the SPI EMIO connection.

    Thank you for the help.. and i hope this topic helps others!

  • 0

    Hi Yousef,

    Glad to see the updated libraries helped. I found the same thing with a problem Iu2019ve been working on for over a month.

    Iu2019m not sure why you say that SS0 does not function via MIO. Itu2019s location on the pMod connector is JE1. This is right where you want it to be, at least for the SPI pMod devices Iu2019ve tested.

    Have you read the ug585-Zynq-7000-TRM.pdf section on SPI? It contains programming examples and wiring diagrams. Iu2019ve found it to be quite useful. It shows SS0 being used via MIO.

    Regards,
    Mike