Summary of Connect ADC with PIC16F877
The article describes an ADC library for PIC microcontrollers, enabling analog-to-digital conversion using internal RC clocks. It details three core routines: `ADC_Init` to configure the module, and `ADC_Get_Sample` or `ADC_Read` to acquire 10 or 12-bit values from specific channels. The library requires MCUs with built-in ADCs, proper TRISx pin configuration, and relies solely on internal voltage references rather than external ones.
Parts used in PIC MCU ADC Library:
- PIC Microcontroller Unit (MCU) with built-in ADC module
- Internal RC Clock
- Analog Input Channels
- TRISx Configuration Bits
- Internal Voltage Reference Source
ADC (Analog to Digital Converter) module is available with a number of PIC MCU modules. ADC is an electronic circuit that converts continuous signals to discrete digital numbers. ADC Library provides you a comfortable work with the module.
Library Routines
ADC_Init
| Prototype | void ADC_Init(); |
|---|---|
| Returns | Nothing. |
| Description | This routine initializes PIC’s internal ADC module to work with RC clock. Clock determines the time period necessary for performing AD conversion (min 12TAD). |
| Requires |
|
| Example |
ADC_Init(); // Initialize ADC module with default settings |
ADC_Get_Sample
| Prototype | unsigned ADC_Get_Sample(unsigned short channel); |
|---|---|
| Returns | 10 or 12-bit unsigned value read from the specified channel (MCU dependent). |
| Description | The function aquires analog value from the specified channel. Parameter channel represents the channel from which the analog value is to be acquired. Refer to the appropriate datasheet for channel-to-pin mapping.
 Note : This function doesn’t work with the external voltage reference source, only with the internal voltage reference. |
| Requires |
|
| Example |
unsigned adc_value; ... adc_value = ADC_Get_Sample(2); // read analog value from ADC module channel 2 |
ADC_Read
| Prototype | unsigned ADC_Read(unsigned short channel); |
|---|---|
| Returns | 10 or 12-bit unsigned value read from the specified channel (MCU dependent). |
| Description | Initializes PIC’s internal ADC module to work with RC clock. Clock determines the time period necessary for performing AD conversion (min 12TAD). Parameter channel represents the channel from which the analog value is to be acquired. Refer to the appropriate datasheet for channel-to-pin mapping.
Note : This function doesn’t work with the external voltage reference source, only with the internal voltage reference. |
| Requires |
|
| Example |
unsigned tmp; ... tmp = ADC_Read(2); // Read analog value from channel 2 |
For more detail: Connect ADC with PIC16F877
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What is the primary function of the ADC library?
The library provides routines to work comfortably with the ADC module that converts continuous signals to discrete digital numbers. -
How does the ADC_Init routine configure the module?
This routine initializes the internal ADC module to work with the RC clock, which determines the time period necessary for AD conversion. -
What data type does ADC_Get_Sample return?
It returns a 10 or 12-bit unsigned value read from the specified channel, depending on the MCU. -
Can ADC_Get_Sample use an external voltage reference source?
No, this function does not work with the external voltage reference source; it only works with the internal voltage reference. -
What must be done before using ADC_Get_Sample or ADC_Read?
You must ensure the ADC module is initialized and configure the appropriate TRISx bits to designate pins as inputs. -
Does ADC_Read perform initialization internally?
Yes, the description states that ADC_Read initializes the PIC internal ADC module to work with the RC clock. -
Where can I find information about channel-to-pin mapping?
You should refer to the appropriate datasheet for channel-to-pin mapping when specifying a channel parameter. -
What is the minimum time period required for AD conversion?
The clock determines the time period necessary for performing AD conversion, with a minimum requirement of 12TAD.
