/**
Update the continuous controllers.
Each time this function is called we process one of the ADC inputs and send
a message to the host.
**/
void ctrl_update( void )
{
unsigned char low, high;
unsigned char curr_ctrl, next_ctrl;
unsigned char sus;
/* Wait for conversion to complete (in theory should already be done) */
while ( !( ADCSRA & ( 1 << ADIF ) ) ) /* spin */ ;
/* Read 10-bit ADC and channel number */
low = ADCL;
high = ADCH;
curr_ctrl = ( ADMUX & 0x0F ) - ADC_OFFSET;
/* Also read the sustain pedal input */
sus = !( PINC & ( 1 << PINC5 ) );
/* Switch to next channel */
next_ctrl = curr_ctrl + 1;
if ( next_ctrl >= MAX_CTRL )
next_ctrl = 0;
ADMUX = ADMUX_CONFIG | ADC_CHAN( next_ctrl );
/* Kick off the next conversion */
ADCSR |= ( 1 << ADSC );
/* Send the value to the master processor */
hostif_msg_ctrl( curr_ctrl, sus, ( ( high << 8 ) | low ) << 2 );
}
static cyg_uint32
adc_sample(int chan)
{
cyg_uint32 val;
*(volatile cyg_uint32 *)SYNCIO = SYNCIO_TXFRMEN | SYNCIO_FRAMELEN(24) |
ADC_START | ADC_CHAN(chan) | ADC_UNIPOLAR | ADC_SINGLE | ADC_EXT_CLOCK;
while (*(volatile cyg_uint32 *)SYSFLG1 & SYSFLG1_SSIBUSY) ;
val = *(volatile cyg_uint32 *)SYNCIO;
return (val & 0xFFFF);
}
/**
Initialise the control reading task.
**/
void ctrl_init( void )
{
/* Clear all but the bottom two bits of DDRC */
DDRC &= ~0x03;
/* Enable the ADC with a conversion clock of 125kHz. */
ADCSRA = ( 1 << ADEN ) | ( 1 << ADPS2 ) | ( 1 << ADPS1 ) | ( 0 << ADPS0 );
/* Select initial channel */
ADMUX = ADMUX_CONFIG | ADC_CHAN( 0 );
/* Kick-off the first conversion */
ADCSR |= ( 1 << ADSC );
}