PIC18F47Q10 Using TMR0 in 8-bit Mode with Periodic Interrupt

Objective

This repository contains an example of bare-metal source code for TMR0 as described in TB3285 - Getting Started with Timers/Counters on PIC18 document from Microchip.

This example describes how to configure Timer0 in 8-bit mode and to generate a compare interrupt every 100 ms using LFINTOSC as clock source.
A GPIO pin (the development board’s on-board LED) will be configured as output and toggled each time the interrupt occurs.
Additionally, the main clock will use a separate clock source (HFINTOSC) and Timer0 will run asynchronously from the main clock.

Related Documentation

• TB3285 - Getting Started with Timers/Counters on PIC18
• PIC18-Q10 Product Family Page
• PIC18F47Q10 Data Sheet
• PIC18F47Q10 Code Examples on GitHub

Software Used

• MPLAB® X IDE 5.30 or newer (microchip.com/mplab/mplab-x-ide)
• MPLAB® XC8 2.10 or newer (microchip.com/mplab/compilers)
• Microchip PIC18F-Q Series Device Support 1.3.89 or newer (packs.download.microchip.com/)

Hardware Used

• PIC18F47Q10 Curiosity Nano (DM182029)

Setup

The PIC18F47Q10 Curiosity Nano Development Board is used as the test platform.

The following configurations must be made for this project:

• Clock – Oscillator Select: HFINTOSC – HF Internal Clock: 1 MHz – Clock Divider: 1
• TMR0
  • TMR0 Enabled
  • Clock Prescaler: 1:16
  • Postscaler: 1:1
  • Timer mode: 8-bit
  • Clock Source: LFINTOSC
  • Synchronization: disabled
  • Timer period: 100 ms
  • Timer interrupt: enabled
• Watchdog Timer: disabled
• Low-voltage Programming: enabled

Pin	Configuration
RE0 (LED0)	Digital Output

Operation

1. Connect the board to the PC.

2. Open the pic18f47q10-cnano-tmr0-8bit-cmp-int-bare.X project in MPLAB® X IDE.

3. Set pic18f47q10-cnano-tmr0-8bit-cmp-int-bare project as main project. Right click on the project in the Projects tab and click Set as Main Project:
   

4. Select the PIC18F47Q10 Curiosity Nano in the Hardware Tool section of the project settings:

• Right click on the project and click Properties;
• Select the PIC18F47Q10 Curiosity Nano (click on the SN) in the Hardware Tool tab and then click OK:
  

5. Program the project to the board: right click on the project and click Make and Program Device:
   

Demo:

Summary

This project is an illustration for a basic use case based around TMR0.