int main(int argc, char **argv){
setvbuf (stdout, NULL, _IONBF, 0); // needed to print to the command line
if (open_dac() != 1){ // open the DAC spi channel
exit(1); // if the SPI bus fails to open exit the program
}
set_dac_gain(2); // set the dac gain to 2 which will give a voltage range of 0 to 3.3V
set_dac_voltage(1.2, 1); // set the voltage on channel 1 to 1.2V
set_dac_voltage(2.5, 2); // set the voltage on channel 2 to 2.5V
close_dac();
return (0);
}
int main_pcmmio_dac(int argc, char **argv)
{
int dac;
float low_voltage;
float high_voltage;
float step_voltage;
float current_voltage;
float current_step;
int step_time;
int maximum_time;
uint32_t step_ticks;
bool fail = false;
int elapsed;
/*
* Verify that we have the right number of arguments.
*/
if ( (argc != 3) && (argc != 7) ) {
printf( "Incorrect number of arguments\n" );
PRINT_USAGE();
return -1;
}
/*
* Convert the string arguments into number values
*/
if ( rtems_string_to_int( argv[1], &dac, NULL, 0 ) ) {
printf( "DAC (%s) is not a number\n", argv[1] );
fail = true;
}
if ( rtems_string_to_float( argv[2], &low_voltage, NULL ) ) {
printf( "Voltage (%s) is not a number\n", argv[2] );
fail = true;
}
/*
* Validate the output dac and voltage.
*/
if ( dac < 0 || dac > 7 ) {
puts( "DAC number must be 0-7" );
fail = true;
}
VALIDATE_VOLTAGE( low_voltage );
/*
* Now do a single write to the DAC
*/
if ( argc == 3 ) {
if ( fail ) {
PRINT_USAGE();
return -1;
}
printf( "Write %6.4f to to dac %d\n", low_voltage, dac );
set_dac_voltage(dac, low_voltage);
return 0;
}
/*
* Finish parsing the arguments to do a pattern
*/
fail = false;
if ( rtems_string_to_float( argv[3], &high_voltage, NULL ) ) {
printf( "Voltage (%s) is not a number\n", argv[3] );
fail = true;
}
VALIDATE_VOLTAGE( high_voltage );
if ( rtems_string_to_float( argv[4], &step_voltage, NULL ) ) {
printf( "Step voltage (%s) is not a number\n", argv[4] );
fail = true;
}
VALIDATE_VOLTAGE( step_voltage );
if ( step_voltage < 0.0 ) {
printf( "Step voltage must be greater than 0\n" );
fail = true;
}
if ( rtems_string_to_int( argv[5], &step_time, NULL, 0 ) ) {
printf( "Step time (%s) is not a number\n", argv[5] );
fail = true;
}
if ( rtems_string_to_int( argv[6], &maximum_time, NULL, 0 ) ) {
printf( "Maximum time (%s) is not a number\n", argv[6] );
fail = true;
}
if ( step_time >= maximum_time ) {
printf(
"Step time (%d) must be less than maximum time (%d)\n",
step_time,
maximum_time
);
fail = true;
}
if ( step_time < 0 ) {
printf( "Step time must be greater than 0\n" );
fail = true;
}
if ( maximum_time < 0 ) {
printf( "Maximum time must be greater than 0\n" );
fail = true;
}
/*
* Now write the pattern to the DAC
*/
if ( fail ) {
PRINT_USAGE();
return -1;
}
printf(
"Write %6.4f-%6.4f step=%6.4f stepTime=%d msecs dac=%d max=%d msecs\n",
low_voltage,
high_voltage,
step_voltage,
step_time,
dac,
maximum_time
);
elapsed = 0;
step_ticks = RTEMS_MILLISECONDS_TO_TICKS(step_time);
current_voltage = low_voltage;
current_step = step_voltage;
if ( low_voltage > high_voltage )
current_step *= -1.0;
while (1) {
#if defined(TESTING)
printf( "%d: Write %6.4f to to dac %d\n", elapsed, current_voltage, dac );
#endif
set_dac_voltage(dac, current_voltage);
current_voltage += current_step;
if ( current_voltage < low_voltage ) {
current_step = step_voltage;
current_voltage = low_voltage;
} else if ( current_voltage > high_voltage ) {
current_step = -1.0 * step_voltage;
current_voltage = high_voltage;
}
elapsed += step_time;
if ( elapsed > maximum_time )
break;
rtems_task_wake_after( step_ticks );
}
return 0;
}
