3 Combinations of Analog Peripherals in PIC16F17146

This section describes the possible interconnections between intelligent analog peripherals of the PIC16F17146 family of microcontrollers and covers details on different analog peripheral combinations which are useful to develop various sensing and measurement applications.

Figure 3-1. Analog Peripheral Interconnections

The possible combinations of analog peripherals are depicted in Figure 3-1.

FVR:

  • Provides 1.024, 2.048 or 4.096V of output voltage.
  • The user can configure the FVR module as a positive voltage reference to the ADC module or DAC module based on the required dynamic range.
  • The FVR module output can be connected to either a positive or negative input channel of the CMP module or to the ADC input channel.

DAC:

  • The DAC module accepts either FVR (buffer 2) or VDD as the positive reference.
  • The 8-bit DAC with 1.024V reference voltage can provide an analog output resolution of 4 mV (1.024V/28).
  • The buffered DAC module output can source current and be configured to connect to the external port pin.
  • The DAC module output can be configured to internally connect to either the OPA module or CMP module or to the ADC input channels.

CMP:

  • The CMP module can be used for auto-triggering the ADC module to start conversion upon comparator output change event.
  • The DAC module or FVR module can be connected to the CMP module input channel and used as a voltage reference to compare external analog signals.

OPA:

  • The OPA module output can be connected to the ADC input channels.
  • Used in signal conditioning circuits. The OPA module can be used as a gain stage or high-impedance stage for an analog signal before connecting to the ADC input channel. It helps in measuring an analog signal with better voltage precision and a higher dynamic range.
  • The DAC module output can be connected to the non-inverting input of the OPA and provides an offset voltage.

ADC:

  • The ADC module accepts either VDD or FVR or an external reference voltage at the VREF+ pin as the reference voltage (VREF).
  • A lower voltage reference provides a higher precision but minimizes the dynamic range of the input signal. For example, with a maximum input voltage of 2.048V and 2.048V voltage reference (VREF), the step size of the 12-bit ADC module conversion result is approximately 500 µV (2.048V/ 212).
  • In ADC Differential mode operation, the DAC module can add an offset voltage to the analog input signal.