Nuts and Volts - September 2016

the pin assignments for the PIC32MM0064GLP028 peripherals that we have previously activated are displayed. The most recent pin assignment is AN0, which happens to be the pin we selected for our ADC analog input. The name of pin RA0 (AN0) is user selectable and is named within the pin module window shown in Screenshot 4.

Our SYSTEM_Initialize function list is growing with the addition of the ADC peripheral to our project mix:

void SYSTEM_Initialize(void)
{
 PIN_MANAGER_Initialize();
 OSCILLATOR_Initialize();
 INTERRUPT_Initialize();
 ADC1_Initialize();
 UART1_Initialize();
 INTERRUPT_GlobalEnable();
}

In addition, two new files — adc1.c and adc1.h — have been automatically added to our

■ SCREENSHOT 3. Setting up an ADC is just a couple of clicks of finger work. Once the ADC parameters are fed into the MPLAB Code Configurator GUI, an analog input pin can be selected from the Code Configurator pin module.

MPLAB X PIC32MM0064GLP028 project. A complement of ADC driver functions was also generated:

void ADC1_Initialize (void);
void ADC1_Start(void);
void ADC1_Stop(void);
uint16_t ADC1_ConversionResultBufferGet
  (uint16_t  *buffer);
uint16_t ADC1_ConversionResultGet(void);
bool ADC1_IsConversionComplete( void );
void ADC1_ChannelSelect( ADC1_CHANNEL
  channel );
void ADC1_Tasks(void);

As you would expect, the MPLAB Code Configurator kindly provided some example code. Here’s a generic ADC sample sequence

int conversion;
ADC1_Initialize();
ADC1_ChannelSelect(AN1_Channel);
ADC1_Start();
//Provide Delay
for(int i=0;i <1000;i++)
{
}

■ SCREENSHOT 4. The Pin Manager display is always accessible.

Once you select a pin in the Pin Manager or via a peripheral assignment, you can transition to the pin module window to configure the selected pin’s behavior and human-readable name.

 ADC1_Stop();
 while(!ADC1_IsConversionComplete())
 {
 ADC1_Tasks();
 }
 conversion = ADC1_ConversionResultGet();

void ADC1_Start(void)
 {
 AD1CON1bits.SAMP = 1;
 }
 void ADC1_Stop(void)
 {
 AD1CON1bits.SAMP = 0;
 }
 uint16_t ADC1_ConversionResultGet(void)
 {
 return ADC1BUF0;
 }