On Thu, Mar 5, 2009 at 05:47, solarwind <x.solarwind.x@gmail.com> wrote:

> Can someone please tell me if I am doing this correctly? My code his here:
> http://pastebin.com/f244a02f3

Looks okay to me, even if the code is not complete.

Here's another example that I wrote for testing a digital
potentiometer using SPI. Perhaps you can steal some of it:


__CONFIG(UNPROTECT & LVPDIS & BORDIS & MCLREN & WDTDIS & PWRTDIS & INTIO);

void delay() {
    int delayer = 10;
    while (delayer != 0) {
        delayer -= 1;
    }

    return;
}

void spi_write(unsigned char data) {
   unsigned char i, j;
    for (i = 1; i < 9; i++) {
        RB2 = 0;
        j = 1 << (8-i);                         // MSB first
        if (data & j)
            RB2 = 1;                            // If data, pulse data line
        RB1 = 1;                                // Pulse clock
        RB1 = 0;
    }
}

void main() {
    unsigned char resistance = 0, op = 0;
    OPTION = 0;
    VRCON = 0;
    EECON1 = 0;
    TRISA = 0;
    TRISB = 0;
    CMCON = 0x7;
    INTCON = 0;
    PORTA = 0;
    PORTB = 0;

    // Neverending loop
    // RB0: Chip select (active low)
    // RB1: SPI-clock
    // RB2: SPI-data
    while (1) {
        RB0 = 0;                                // Make digipot active
        spi_write(0b00001001);                  // Write data / All pots
        spi_write(resistance);                  // Update the resistance
        RB0 = 1;                                // Disable pot

        if (resistance > 127)
            op = 1;
        else if (resistance == 0)
            op = 0;

        if (op)
            resistance -= 1;
        else
            resistance += 1;
    }
}

What it does is to send the values 0..127 (back and forth) to the
digipot while I measured it using a DMM. It was run on a low clocked
PIC (32kHz I think), and that's why I don't use any delay-routines for
the strobing.


-- 
- Rikard - http://bos.hack.org/cv/
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