cy22150.c

// system includes
#include "global.h"

// local includes
#include "i2c.h"
#include "cy22150.h"

// functions
void cy22150Init(void)
{
    // set dividers to default
    cy22150WriteReg(CY22150_REG_DIV1, 8);
    cy22150WriteReg(CY22150_REG_DIV2, 8);

    // set crystal capacitor loading to 20pf
    // Capload = (Cload-(Cboard+Cchip))/0.09375pF
    // (20pF-(2pF+6pF))/0.09375 = 128
    cy22150WriteReg(CY22150_REG_CAPLOAD, (u08)((20-(2+6))/0.09375) );
}


void cy22150SetOutput(u08 clkpin, u08 enable)
{
    // enable/disable requested output pin
    if(enable)
        cy22150WriteReg(CY22150_REG_CLKOE, cy22150ReadReg(CY22150_REG_CLKOE) | (1<<clkpin));
    else
        cy22150WriteReg(CY22150_REG_CLKOE, cy22150ReadReg(CY22150_REG_CLKOE) & ~(1<<clkpin));
}

void cy22150SetDiv(u08 divreg, u08 div)
{
    switch(divreg)
    {
    case 0: cy22150WriteReg(CY22150_REG_DIV1, div); break;
    case 1: cy22150WriteReg(CY22150_REG_DIV2, div); break;
    }
}

void cy22150SetQ(int q)
{
    if(q<2)
        return; // error: q must be at least 2
    // write q value with PO bit masked
    cy22150WriteReg(CY22150_REG_QCNT, ((q-2)&0x7F) );
}

void cy22150SetP(int p)
{
    u08 pump;
    int pb;

    // calculate pump value from p multiplier
    if(p<45)        pump = 0;
    else if(p<480)  pump = 1;
    else if(p<640)  pump = 2;
    else if(p<800)  pump = 3;
    else            pump = 4;

    // calculate pb from p value
    pb = (p/2)-4;

    // write p value
    cy22150WriteReg(CY22150_REG_PBHI, 0xC0 | (pump<<2) | ((pb>>8)&0x03) );
    cy22150WriteReg(CY22150_REG_PBLO, (pb&0xFF) );
}

void cy22150WriteReg(u08 addr, u08 data)
{
    u08 packet[2];
    // prepare write packet
    packet[0] = addr;
    packet[1] = data;
    // write to device  
    i2cMasterSend(CY22150_I2C_ADDR, 2, packet);
}

u08 cy22150ReadReg(u08 addr)
{
    u08 data;
    // select register to read
    i2cMasterSend(CY22150_I2C_ADDR, 1, &addr);
    // read value
    i2cMasterReceive(CY22150_I2C_ADDR, 1, &data);
    // return value
    return data;
}

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