Jordan Barry Victor Brzeski TM4C123g ADC Peripheral Jordan Barry Victor Brzeski

Brief Overview Samples, and converts an analog voltage to a digital value Used frequently in sensor measurement Conversion triggered via SWI or HWI

TM4C123g MCU’s ADC Two ADC modules 12-bit Precision 12 Input Channels each 12-bit Precision Maximum sample rate of 1 million samples/second FIFO buffers Trigger Control SWI Timers Analog Comparators PWM interrupts GPIO Interrupts

Hardware Interface Results are bound via VREFP and VREFN These are internally connected to analog supply voltage/GND Sample Averaging Circuit Averages 4 samples during conversion Useful for noisy signals Differential Sampling Difference of 2 channels Internal Temperature Sensor Can be sampled for chip temp

TI API Example Using the TI API functions listed at: TI's Website we use their short example given: Enable the channel desired for when trigger occurs Trigger sample sequence (Event Occurs eg. SWI, HWI) Wait for ADC conversion to complete (Semaphore) Read value from ADC result FIFO registers

Code Provided by TI

Triggers - \b ADC_TRIGGER_PROCESSOR - A trigger generated by the processor, via the //! ADCProcessorTrigger() function. //! - \b ADC_TRIGGER_COMP0 - A trigger generated by the first analog //! comparator; configured with ComparatorConfigure(). //! - \b ADC_TRIGGER_COMP1 - A trigger generated by the second analog //! - \b ADC_TRIGGER_COMP2 - A trigger generated by the third analog //! - \b ADC_TRIGGER_EXTERNAL - A trigger generated by an input from the Port //! B4 pin. Note that some microcontrollers can //! select from any GPIO using the //! GPIOADCTriggerEnable() function. //! - \b ADC_TRIGGER_TIMER - A trigger generated by a timer; configured with //! TimerControlTrigger(). //! - \b ADC_TRIGGER_PWM0 - A trigger generated by the first PWM generator; //! configured with PWMGenIntTrigEnable(). //! - \b ADC_TRIGGER_PWM1 - A trigger generated by the second PWM generator; //! - \b ADC_TRIGGER_PWM2 - A trigger generated by the third PWM generator; //! - \b ADC_TRIGGER_PWM3 - A trigger generated by the fourth PWM generator; //! - \b ADC_TRIGGER_ALWAYS - A trigger that is always asserted, causing the //! sample sequence to capture repeatedly (so long as //! there is not a higher priority source active).

Interrupts //! - \b ADC_INT_SS0 - interrupt due to ADC sample sequence 0. //! - \b ADC_INT_SS1 - interrupt due to ADC sample sequence 1. //! - \b ADC_INT_SS2 - interrupt due to ADC sample sequence 2. //! - \b ADC_INT_SS3 - interrupt due to ADC sample sequence 3. //! - \b ADC_INT_DMA_SS0 - interrupt due to DMA on ADC sample sequence 0. //! - \b ADC_INT_DMA_SS1 - interrupt due to DMA on ADC sample sequence 1. //! - \b ADC_INT_DMA_SS2 - interrupt due to DMA on ADC sample sequence 2. //! - \b ADC_INT_DMA_SS3 - interrupt due to DMA on ADC sample sequence 3. //! - \b ADC_INT_DCON_SS0 - interrupt due to digital comparator on ADC sample //! sequence 0. //! - \b ADC_INT_DCON_SS1 - interrupt due to digital comparator on ADC sample //! sequence 1. //! - \b ADC_INT_DCON_SS2 - interrupt due to digital comparator on ADC sample //! sequence 2. //! - \b ADC_INT_DCON_SS3 - interrupt due to digital comparator on ADC sample //! sequence 3.

Logic flow – Interrupt Based Set ADC trigger to a SWI, at a specific sampling period Eg. ADC_TRIGGER_TIMER via RTOS Configure ADC to interrupt when ADC sample sequence is complete Eg. ADC_INT_SS0 Sample values from FIFO Register Read from SSFIFO3 Register Send values to PID or bang/bang algorithm Adjust motor duty cycle

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