Silicon Laboratories Stepper Machine User Manual download pdf (Page 23)

AN428

Rev. 0.6 23

INTERRUPT_PROTO(SMBus_ISR, INTERRUPT_SMBUS0);

INTERRUPT_PROTO(Timer2_ISR, INTERRUPT_TIMER2);

void I2C_ByteWrite (U8 addr, U8 dat);

U8 I2C_ByteRead (U8 addr);

//-----------------------------------------------------------------------------

// MAIN Routine

//-----------------------------------------------------------------------------

void main (void){

U16 counter;

U8 curr_chip_val, clear_curr_val, clear_new_val, combined, reg;

Reg_Data curr;

U8 i; // Temporary counter variable used in for loops

PCA0MD &= ~0x40; // WDTE = 0 (disable watchdog timer)

OSCICN |= 0x03; // Configure internal oscillator for

// its maximum frequency (24.5 Mhz)

// If slave is holding SDA low because of an improper SMBus reset or error

while(!SDA)

{

// Provide clock pulses to allow the slave to advance out

// of its current state. This will allow it to release SDA.

XBR1 = 0x40; // Enable Crossbar

SCL = 0; // Drive the clock low

for(i = 0; i < 255; i++); // Hold the clock low

SCL = 1; // Release the clock

while(!SCL); // Wait for open-drain

// clock output to rise

for(i = 0; i < 10; i++); // Hold the clock high

XBR1 = 0x00; // Disable Crossbar

}

Port_Init (); // Initialize Crossbar and GPIO

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Silicon Laboratories Stepper Machine User Manual Page 23