[partial-reconfig] Write/Read data on SRAM

["Paolo Furia" <paolo.furia@xxxxxxxxx>]

Hi all,
I'm trying to write data (a partial bitstream) on SRAM and then read them. I'm working on a ML402 (with a virtex-4 fpga) and I send the data through RS232. I've a Microblaze on my system that manage all.
I use the following C code:


/* BITSTREAM_BASEADDR is the base address of SRAM */

     char buf, val;
     int i;
     Xuint32 baseaddr = BITSTREAM_BASEADDR;
   
     for (i=0; i<50492; i++){
     
        buf = XUartLite_RecvByte(UART_BASEADDR);
       
        XIo_Out8((baseaddr+i), buf);
              
        }
       
       
        xil_printf("Bitstream stored!\n\r");
               
       
        xil_printf("High address: %d\n\r", (baseaddr+i));
       

        /***** Cycle to read the first 10 values stored *****/
       
        xil_printf("value: %x\n\r\n\r", val);
       
        xil_printf("\n Primi 10 valori salvati:\n\r\n");
       
        for (i=0; i<10; i++){
       
        val = XIo_In8((BITSTREAM_BASEADDR+i));
       
        xil_printf("valore: %x\n\r\n\r", val);
       
        }
       
        /***** End of cycle *****/



The first 10 values of the file I send are: FF FF FF FF 55 99 AA 66 04 00.
But Microblaze reads from memory this: FFFFFFFF, FFFFFFFF, FFFFFFFF, FFFFFFFF, 55, FFFFFF99, FFFFFFAA, 66, 4, 0.
I tried sending other values and I discovered that alla values between 0 and 127 are displayed well, while the values from 128 to 255 are dysplayed with FFFFFF ahead. Why? Do you have any suggestion? I'd very appreciate any help.

Regards,

Paolo Furia