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; }