Part Number: TMS320F280039C
Other Parts Discussed in Thread: SYSCONFIG
Hello,
My ADCs are reading half of the expected counts. If I apply 1.5V to the ADC I get 1024 instead of 2048. I feel like I have the scaling wrong somewhere.
I added this to my initialization since I saw SysConfig generated this for the demo projects.
// asysctl initialization
// Disables the temperature sensor output to the ADC.
ASysCtl_disableTemperatureSensor();
// Set the analog voltage reference selection to internal.
ASysCtl_setAnalogReferenceInternal( ASYSCTL_VREFHI );
// Set the internal analog voltage reference selection to 1.65V.
ASysCtl_setAnalogReference1P65( ASYSCTL_VREFHI );
I also have the voltage reference set to 3.3V as I want:
// Set ADC voltage ref
ADC_setVREF(adcHandle[0], ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
ADC_setVREF(adcHandle[1], ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
ADC_setVREF(adcHandle[2], ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
ADC_setOffsetTrimAll(ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
This is my ADC init code -
void Setup_FastADC()
{
// Select interrupt source - this will be the last sample converted and therefore trigger the interrupt 1
ADC_setInterruptSource(ADCC_BASE, ADC_INT_NUMBER1, ADC_DCBUS_SOCNUM);
// Setup ADCs for PhA - this is triggered based off of counter EPWM1 SOCA (setup below)
// Sample window must be > 75ns per datasheet, > 90ns for AGPIO per datasheet (at least > 11 SYSCLK cycles to be safe - 91.3ns)
// Sample window must also be as long as 1 ADC clock cycle (40ns) - input sample window in SysClk cycles (11 cycle = 91.3ns)
ADC_setupSOC(ADC_PHA_I_BASE, ADC_PHA_I_SOCNUM, ADC_TRIGGER_EPWM1_SOCA, ADC_PHA_I_CHANNEL, ADC_SAMPLE_WINDOW);
ADC_setInterruptSOCTrigger(ADC_PHA_I_BASE, ADC_PHA_I_SOCNUM, ADC_INT_SOC_TRIGGER_NONE);
// Configuring PPB in case we have any calibration to do
// Configure PPB to subtract out any offset
// PPB is associated with ADCA_SOC1
// ADC_setupPPB(ADC_PHA_I_BASE, ADC_PHA_I_PPBNUM, ADC_PHA_I_SOCNUM);
//
// // Write 0 to PPB will disable PPB offset calibration (change 0 to the offset we want if we need)
// ADC_setPPBCalibrationOffset(ADC_PHA_I_BASE, ADC_PHA_I_PPBNUM, 0);
// Setup ADCs for PhB - this is triggered based off of counter EPWM1 SOCA (setup below)
// Sample window must be > 75ns per datasheet, > 90ns for AGPIO per datasheet (at least > 11 SYSCLK cycles to be safe - 91.3ns)
// Sample window must also be as long as 1 ADC clock cycle (40ns) - input sample window in SysClk cycles (11 cycle = 91.3ns)
ADC_setupSOC(ADC_PHB_I_BASE, ADC_PHB_I_SOCNUM, ADC_TRIGGER_EPWM1_SOCA, ADC_PHB_I_CHANNEL, ADC_SAMPLE_WINDOW);
ADC_setInterruptSOCTrigger(ADC_PHB_I_BASE, ADC_PHB_I_SOCNUM, ADC_INT_SOC_TRIGGER_NONE);
// // Configuring PPB in case we have any calibration to do
// // Configure PPB to subtract out any offset
// // PPB is associated with ADCB_SOC1
// ADC_setupPPB(ADC_PHB_I_BASE, ADC_PHB_I_PPBNUM, ADC_PHB_I_SOCNUM);
//
// // Write 0 to PPB will disable PPB offset calibration (change 0 to the offset we want if we need)
// ADC_setPPBCalibrationOffset(ADC_PHB_I_BASE, ADC_PHB_I_PPBNUM, 0);
// Setup ADCs for PhC - this is triggered based off of counter EPWM1 SOCA (setup below)
// Sample window must be > 75ns per datasheet, > 90ns for AGPIO per datasheet (at least > 11 SYSCLK cycles to be safe - 91.3ns)
// Sample window must also be as long as 1 ADC clock cycle (40ns) - input sample window in SysClk cycles (11 cycle = 91.3ns)
ADC_setupSOC(ADC_PHC_I_BASE, ADC_PHC_I_SOCNUM, ADC_TRIGGER_EPWM1_SOCA, ADC_PHC_I_CHANNEL, ADC_SAMPLE_WINDOW);
ADC_setInterruptSOCTrigger(ADC_PHC_I_BASE, ADC_PHC_I_SOCNUM, ADC_INT_SOC_TRIGGER_NONE);
// // Configuring PPB in case we have any calibration to do
// // Configure PPB to subtract out any offset
// // PPB is associated with ADCC_SOC1
// ADC_setupPPB(ADC_PHC_I_BASE, ADC_PHC_I_PPBNUM, ADC_PHC_I_SOCNUM);
//
// // Write 0 to PPB will disable PPB offset calibration (change 0 to the offset we want if we need)
// ADC_setPPBCalibrationOffset(ADC_PHC_I_BASE, ADC_PHC_I_PPBNUM, 0);
// If we need any more PBB's we can copy them from above
// Setup DCLink sampling -> This will trigger interrupt
ADC_setupSOC(ADC_DCBUS_BASE, ADC_DCBUS_SOCNUM, ADC_TRIGGER_EPWM1_SOCA, ADC_DCBUS_CHANNEL, ADC_SAMPLE_WINDOW);
ADC_setInterruptSOCTrigger(ADC_DCBUS_BASE, ADC_DCBUS_SOCNUM, ADC_INT_SOC_TRIGGER_NONE);
}
void Init_ADC()
{
// asysctl initialization
// Disables the temperature sensor output to the ADC.
ASysCtl_disableTemperatureSensor();
// Set the analog voltage reference selection to internal.
ASysCtl_setAnalogReferenceInternal( ASYSCTL_VREFHI );
// Set the internal analog voltage reference selection to 1.65V.
ASysCtl_setAnalogReference1P65( ASYSCTL_VREFHI );
// Setup ADC
// Three ADC modules in this device
// initialize the ADC handles
adcHandle[0] = ADCA_BASE;
adcHandle[1] = ADCB_BASE;
adcHandle[2] = ADCC_BASE;
// initialize the ADC results
adcResult[0] = ADCARESULT_BASE;
adcResult[1] = ADCBRESULT_BASE;
adcResult[2] = ADCCRESULT_BASE;
// Set ADC voltage ref
ADC_setVREF(adcHandle[0], ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
ADC_setVREF(adcHandle[1], ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
ADC_setVREF(adcHandle[2], ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
ADC_setOffsetTrimAll(ADC_REFERENCE_INTERNAL, ADC_REFERENCE_3_3V);
// Set main clock scaling factor (60MHz max clock for the ADC module)
// ADC clock set up for 30 MHz
ADC_setPrescaler(adcHandle[0], ADC_CLK_DIV_2_0);
ADC_setPrescaler(adcHandle[1], ADC_CLK_DIV_2_0);
ADC_setPrescaler(adcHandle[2], ADC_CLK_DIV_2_0);
// Set the ADC interrupt pulse generation to end of conversion
ADC_setInterruptPulseMode(adcHandle[0], ADC_PULSE_END_OF_CONV);
ADC_setInterruptPulseMode(adcHandle[1], ADC_PULSE_END_OF_CONV);
ADC_setInterruptPulseMode(adcHandle[2], ADC_PULSE_END_OF_CONV);
// Disables SOC burst mode.
ADC_disableBurstMode(adcHandle[0]);
ADC_disableBurstMode(adcHandle[1]);
ADC_disableBurstMode(adcHandle[2]);
// Set priority of SOCs
ADC_setSOCPriority(adcHandle[0], ADC_PRI_ALL_HIPRI);
ADC_setSOCPriority(adcHandle[1], ADC_PRI_ALL_HIPRI);
ADC_setSOCPriority(adcHandle[2], ADC_PRI_ALL_HIPRI);
// Enable ADCs
ADC_enableConverter(adcHandle[0]);
ADC_enableConverter(adcHandle[1]);
ADC_enableConverter(adcHandle[2]);
// Delay to allow ADCs to power up
SysCtl_delay(5000U);
// Setup ADCs for fast samples - A, B, C, DC Link
Setup_FastADC();
// Init motor PWM to trigger ADC
MotorPWM_Init();
// Enable ADC interrupt - Enables ADC interrupts in group 1 - priority 12
// Kicks off the fast thread
Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP1);
Interrupt_register(INT_ADCC1, &adcC1ISR); // register ISR
}
Thanks for the help!
