8-bit MicrocontrollersのトピックRe: [MC9S08JM60] Problems with MCU SPI slave

[MC9S08JM60] Problems with MCU SPI slave

Koolmelee — Wed, 04 Aug 2010 21:27:23 GMT

So I have 2 MC9S08JM60 microcontrolers that I have connected through spi.

I have the master MCU sending data out properly (I have scoped this out-->clk, data and chip select and the signals look great on both the output pins of the master MCU and the input pins of the slave MCU.) However, the problem lies in the slave. I poll SPRF, but it never seems to get set.

Here is my initialization for the Slave MCU.

void MCU1COMM_init() {

/*Pin Initialization*/


   /*SPI module initialization*/


      SOPT2_SPI2FE = 0;       //Disable the spi filter for > 6Mhz transmission

        //--SPI Control Register 1--
         //No interrupts,
         //SPI enabled,
         //Normal polarity/phase(active high clk),
         //slave mode
         //MSB first,

      SPI2C1 = SPI2C1_SPE_MASK; //Enable

         //--SPI Control Register 2--
         //Disable interrupts
         //16 bit transfers
         //Master mode fault disabled
         //Bidirectional disabled
         //Spi stop in wait mode
         //spi pin control disabled
      SPI2C2 = SPI2C2_SPIMODE_MASK;   // 16 bit xfer


}

Here is the function I call in a loop continuously in the main

UINT8 SPI_MCU1Read()
{
     UINT8 temp1=0, temp2=0;
     UINT8 index;
     UINT8 result = 0;

     if(SPI2S_SPRF)   //data has been recieved
     {

        temp1 = SPI2DH;
        temp2 = SPI2DL;

         if(temp1 == DATAINCOMING)
         {
             result = 1;
             for(index = 0; index < temp2; index++)   //recieve 16 bytes
             {

                 while(!SPI2S_SPRF);     //wait for read flag to be set

                 MCU1_Datain[index] = SPI2DH;       //grab the data
                 MCU1_Datain[index + 1] = SPI2DL;

             }

         }


     }



     return result;
}

Re: [MC9S08JM60] Problems with MCU SPI slave

PeterHouse — Thu, 05 Aug 2010 03:13:16 GMT

Make sure you connected the Master MISO to Slave MOSI and the Master MOSI to Slave MISO. Good Luck, Peter

Re: [MC9S08JM60] Problems with MCU SPI slave

bigmac — Thu, 05 Aug 2010 11:07:10 GMT

Hello,

MISO pins must connect together at each end, as must the MOSI pins. For the SPI module, MISO is an input for master operation, and an output for slave operation, and vice versa for MOSI. The switching between input and output is done within the module hardware.

If you are attempting to single step through the function SPI_MCU1Read(), in all probabilily the debugger's actions will clear the flag before the test can occur within the code. Use a suitable break point rather than single stepping.

Since you have used macros for the SPI initialisation, it is impossible to confirm whether the actual initialisation matches to your stated intent, without knowing the value of each macro.

Regards,

Mac

Re: [MC9S08JM60] Problems with MCU SPI slave

PeterHouse — Thu, 05 Aug 2010 20:00:09 GMT

Oops. My Mistake. My lame excuse is I used SPI before they were called MOSI and MISO and before they were switched by the hardware and you had to cross connect them. Who made me a trusted contributor anyway ??? Peter