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SSP1 Problem - Serial Mem. Communication

Hi u all!

I'm facing a problem here, I'm trying to develop a serial flash memory interface here.
The memory is M25P128, and I'm using LPC2368.

The thing is..I don't have much experience with SPI/SSP.
Well.. I've downloaded some examples but I couldn't establish the communication appropriately.
Ideally I should have an oscilloscope to check all this, but..

The following code just try to request from the memory its status register:

int InitSSP()
{
        PCONP = 1<<10;
        PINSEL0 = 0xA8000;
        PINMODE0 = 0xA8000;// Here is my first doubt, the pins should be configured with pull-up or not?

        //INTERRUPT
        VICVectAddr11 = (unsigned long) SSP_Isr;
        VICVectCntl11 = 0;
        VICIntEnable |= 0x800; // 11th bit is the SSP1

        FIO2DIR1 = (1<<3); //SS Pin - configured as output

        SSP1CR1 = 0;//SSP disable
        SSP1CR0 = 0x07;
        SSP1CPSR= 10;
        SSP1IMSC = 3;//Receives int
        SSP1CR1 = 2;

}

void SSP_Isr(void) __irq
{
        spiBuf[0] = SSP1DR;
        VICVectAddr = 0; // reset VIC
        FIO2PIN1  = 1<<3;//HIGH
}

int WriteFlash()//Adress, Data, size
{

    FIO2PIN1  = 1<<3;     //HIGH
    FIO2PIN1  = 0<<3;     //LOW

    SSP1DR = 0x05; //Instrução WREN
    while (!(SSP1SR & SSPSR_BSY));

    //FIO2PIN1  = 1<<3;   //HIGH - In this test I set the High signal in the interruption method because it should be set after receive the message from the memory

}

The problem is, doesn't matter which instruction I send I still receive answers that doesn't make any sense! And should be just a few specific instructions that the memory should answer back.

thanks

Parents
  • One transistor and some R/C is OK with you? Actually if you need full Vcc swing you need to amplify it so may it's not so good idea but it will buffer signals.

    The 74F series can oscillate with a crystal but the layout is very critical and if not done right can result in the oscillator not starting up or starting up intermittently. Because of this I prefer to use crystal modules at higher frequency's. You could use 74AC or 74ACT at 3.3V if you can find them. Alternatively you could use a transistor but the layout is very critical and it is hard to get reliable start up.

Reply
  • One transistor and some R/C is OK with you? Actually if you need full Vcc swing you need to amplify it so may it's not so good idea but it will buffer signals.

    The 74F series can oscillate with a crystal but the layout is very critical and if not done right can result in the oscillator not starting up or starting up intermittently. Because of this I prefer to use crystal modules at higher frequency's. You could use 74AC or 74ACT at 3.3V if you can find them. Alternatively you could use a transistor but the layout is very critical and it is hard to get reliable start up.

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