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CCS C Compiler for Microchip PIC micros

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C sample code for PIC micros and Hi-Tech C

Sample projects for the Microchip PIC micro series of microcontrollers, including the PIC12x, PIC16x, PIC18x, PIC24x, and dsPICx microcontrollers.

Code is targeted at the Hi-Tech C compiler, from, the C18 or C30 compiler from, or CCS C.

We want to publish your embedded source code for the benefit on the PIC community. Send it to support@microchipc.comand I will post it on the site, together with recognition of your name and website.

Sample C Code (set A)

Types for Hi-Tech C

  • Data Types for Hi-Tech C, from Eduardo Rosso. Reasonably well known code, makes handling of data easier.

    Data types for Hi-Tech C.

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Delay and Timeout Routines for Hi-Tech C (PIC16Fx core)

  • Example project illustrating delay and timeout routines.

    Unlike the routines available from the Hi-Tech C site, these are written in in-line assembler and thus give precise timing.  Remember to match the actual microprocessor clock speed to the setting for PIC_CLK.

  • Delay routines v7.1 for Hi-Tech C and PIC16x core.

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Delay and Timeout Routines for Hi-Tech C (PIC18Fx core)

  • Example project illustrating delay and timeout routines.

    Unlike the routines available from the Hi-Tech C site, these are written in in-line assembler and thus give precise timing.  Remember to match the actual microprocessor clock speed to the setting for PIC_CLK.

    Note: these routines could cause problems if Hi-Tech C banks the assembly variables in the incorrect bank; the problem would only surface on a large project with high RAM usage. See file "Warning_deprecated_routines.txt" within the archive for an alternative solution.

  • Delay routines v2.2 for Hi-Tech C and PIC18x core.

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RS232 Serial port

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USB Serial port on PIC18F4550

  • USB example for PIC18F4550. Plug your PIC18F4550 into your PC using a USB cable. A virtual RS232 COM port is created, allowing your application to print RS232 messages into HyperTerminal. Allows porting of legacy code that used RS232 comms.

    This project is a modified form of the CDC (Communications Class Driver) available from The forum has some discussion on this code.

    Note: ensure that you read "readme (including install notes).txt" after download.

    Schematics: this code runs on the PICDEM-FS board from Microchip. To make your own schematic, place a PIC18F4550 on a breadboard, ensure that you are using a 20Mhz crystal, place a 470nF capacitor on port Vusb, and hook the USB directly to the chip. It should start to work straight away. Download the PICDEM-FS datasheet for the exact schematic to use with this code.

    Result: start up HyperTerminal or putty, find the new COMx port that has been enumerated. Set it to 115200,N,8,1. The actual COM port speed doesn't matter, as its a virtual comm port. You will see "[alive]" being continuously generated on virtual com port X over USB. You can find the exact number of the virtual COM port by going into "Control Panel", then "System", then selecting the "Hardware" then "Device Manager", there will be a new COM port under "Ports (COM & LPT). You can change the number of the virtual comm port by going into properties, and selecting the new COM port.

    11th Nov 2007 - tried it on Hi-Tech C v9.62, it worked. Had reports that it does not work on Hi-Tech C v9.51.
    2nd Feb 2009 - customer got it working with Hi-Tech C v9.51, it worked after some tweaks. Added instructions to v1.10 of the download.

    PIC18F4550 USB serial port example:
    Download from GitHub.

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Bootloaders for PIC Microcontrollers

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dsPIC bootloader from Ingenia

This is the source code of the Ingenia dsPIC bootloader.

The bootloader consists of:

  • Open source firmware code, written in assembler. Can be adapted for generic for all dsPIC devices.
  • A Windows based Graphical User Interface. Comes with user's guide, algorithm flow, etc.

The main features of the firmware are:

  • Auto-Baud rate detection. This allows one to use any speed of crystal.
  • Ability to read/write program memory.
  • Ability to read/write EEPROM Memory
  • Ability to read/write configuration registers.
  • Easily add new dsPIC devices. By default comes only with dsPIC30F4011 and dsPIC30F3011. Define and protect memory zones through a XML configuration file.

Forum devoted to the Ingenia bootloader. See feedback from other users of this bootloader.

Or browse directly to the Ingenia bootloader homepage or the Ingenia company homepage.


Download firmware and Windows installer (3.8MB).
Download user manual (442KB).

If you wish to contribute configuration files for this bootloader, for different dsPIC devices, email

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Sample Projects in MPLab for Hi-Tech

  • Example project in MPLab for PIC16F876 and Hi-Tech C 7.86pl2, showing how to output decimals using putch().

  • Extremely simple example of how to efficiently count bits in an integer.

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  • Example Hi-Tech C code for I2C, interfacing to Microchip 24LC01B non-volatile EEPROM and Dallas Temperature sensors DS1775 and DS1721.
    Download (4KB).

  • By Mike Pearce. From readme.txt: "A complete set of bit banged, software driven I2C routines I created for any PIC device - and they work!! These functions are single master only functions, and are ideal for communicating with things like EEPROMs, LCD Drivers, ADC Converters etc.". Intel enquired about using this code in one of their products.

    Download (51KB).

    See Mike Pearces projects below for more.

  • Example code for I2C, routines for PIC16F877 to write to the 24LC01B EEPROM, using the PICDEM 2 demo board from Microchip. By Michael Alon.
    Download (5KB).

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  • Excellent CRC code.

    // Update the CRC for transmitted and received data using
    // the CCITT 16bit algorithm (X^16 + X^12 + X^5 + 1).
    unsigned char ser_data;
    static unsigned int crc;
    crc = (unsigned char)(crc >> 8) | (crc << 8);
    crc ^= ser_data;
    crc ^= (unsigned char)(crc & 0xff) >> 4;
    crc ^= (crc << 8) << 4;
    crc ^= ((crc & 0xff) << 4) << 1;

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    Hi Shane,

    I appreciate the time and effort you spent to make this page, well done !!

    I've been involved with PIC micros since 1996 and programming in
    C (CCS Compiler) for the last two years.

    I want to send you my best regards from Argentina.

    - Humberto

Interfacing to miscellaneous hardware with Hi-Tech C

  • PIC16F876 to PC comms via RS232 with sample Hi-Tech C code and VB 6 code. Link.

  • By Mike Pearce. From readme.txt: Dallas DS1820 Digital Temperature Probe routines for the PIC12Fx and PIC16Fx series. Includes CRC checking routines. Download (19KB). See Mike Pearces projects below for more.

  • PIC and SPI bus for a Linear Tech LTC2404 24 bit A/D module, from Scott Douglas, Project Engineer, Blodgett Combi. Heavily commented implementation. Download (6KB).

  • How to use EEPROM on 12CE673/4. Download (1KB).

  • For a PIC16F87x, how to initialize the built-in 256 bytes of EEPROM at compile time. Download.

  • How to use EEPROM under CCS C for 24LC256. Link.

  • How to use EEPROM under Hi-Tech C for 24LC01. Link.

  • Example A/D code for 12-bit Texas Instruments TLC2543.  Download.

  • Example D/A code for 12-bit Analogue Devices AD7390.  Download.

  • How to use the 93XXX EEPROM chip utilizing built-in hardware SPI for 16X and 17X series micros. Download.

  • Example A/D code for inbuilt ports on PIC16F876/7.  Download.

  • Example C code for SPI to access the following chips.

    • A/D chip, the MAX186 12 bit 8-channel micro-wire and D/A chip, the LTC1446 12 bit 2-channel micro-wire. Download.

  • Example Hi-Tech C code for RS232, Dallas DS1821 temperature probe, I2C, A/D, LCD, keypad, see sample projects below by Mike Pearce.

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Complete Design for Giant 8-foot LCD Counter

This is the complete design for a giant 8 foot money counter for student debt. It is still working beautifully to this day, counting up student debt in the main library at Canterbury University of New Zealand.

Download the complete design, including sample PIC code in C (for PIC16F876 or pIC16F877), Visual Basic code, Protel 99 .pcb files, plans and photos.
Download (1080KB).

Explanation of the time-sliced multitasking used in this project.

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Multitasking on a PIC in Hi-Tech C

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USB to IBM-PC communications using PIC16F876

See the following link for Hi-Tech C source code for interfacing a 16F876 to a PC using a Philips PDIUSBD11 chip. Many thanks to Craig Peacock.

Browse to

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Mechanically scanned display source code in Hi-Tech C

From Rickard Gunée in Norway, the design for a rotor with a row of LEDs on the end. As it spins, it forms pictures. The photo to the right shows a game of tetris implemented on the spinning led rotor! See

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  • Sample projects that come with Hi-Tech C compiler.  Look in directory c:\ht-pic\samples for a/d routines, delay, i2c, interrupt, interrupt serial, software serial, LCD, SCI, timer0 and more.

  • Sample routines that come with the Hi-Tech C compiler.  Look in directory c:\ht-pic\sources for many math, string, and variable routines.

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Sample Hi-Tech C projects by Mike Pearce (set B)

These sample Hi-Tech C projects were supplied by Mike Pearce while he was working at the University of Canterbury, New Zealand. He is an excellent programmer for PIC micros, and manages to make them do things that I barely thought were possible. These projects partially cover the 8+ years of work he performed in the Chemistry Department and as a hobby. They give a window into the way he does his code, and perhaps you will learn a few tricks from him :) Enjoy!

PIC16F84 based pulse monitor with date/time output to an RS232 serial port by Mike Pearce

Here's the scenario: at University of Canterbury, New Zealand, they operate a hugely expensive X-ray crystallography machine. It was water cooled, and each run would take 24 hours and cost the client a lot. Unfortunately, as the story goes, there was a problem with the water supply controller, and it would periodically drop pressure and the machine would shut down. This means the run would have to be started again.

So, Mike Pearce designed a water-monitor. It would measure the flow, based on pulses from a flow meter. If the pulses dropped below a pre-determined threshold, it would log the date and time out to a serial port. They set up a PC with a serial program, and came back the next day to see exactly when the flow had dropped.

Mike tracked down the problem and had the system adapted to counter for the glitches, due to this nice piece of design work.

Download from GitHub.

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PIC16F84 based TRIAC / IGBT phase controller for 50/60Hz brightness control by Mike Pearce

From readme.txt: A single channel phase controller for a PIC16x84 @ 10Mhz. RB0/INT is used for the zero cross detection. RA0 is an active LOW output to an opto isolator to drive a TRIAC or IGBT circuit. Phase control is a simple even time-slice method, with 255 levels of output. This has samples of how to use the interrupt routine for TMR0 and INT. Timing for 50Hz and 60Hz has been included - selectable by commenting out the unwanted option. Also TRIAC or IGBT output is available by commenting out the unwanted option.There is more info in the .c file pertaining to TRIAC/IGBTS and EMI standards.

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PIC12C509 logic gate replacement for nitrogen filler by Mike Pearce

From readme.txt: This project was a really quick replacement for an old logic gate that had faulted and could not be fixed. It is a simple program that uses nested if{}else{} statements to do a BETTER job than the original logic did, by the addition of some error trapping and a timeout delay for safety reasons (and to save money because Liquid Nitrogen is not cheap).

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Demo Board by Mike Pearce

This code was used to drive a demo board that I made for a University of Canterbury demonstration day.

From readme.txt: The demo board consisted of a 16F84, five 240V 3A solid state relays, an RS-232 port, a Dallas 1-wire interface port (using a RJ-11/12 connector), and a number of LEDs ...

The archive contains the Hi-Tech C source code, Protel 99 schematic and pcb files, and .jpg schematic.

  • Schematic for demo board. View.

  • Entire archive. Download (180KB).

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Heater Project by Mike Pearce

From readme.txt: The Heater 3 project is used to control waterbath heaters and other specialist temperature controlled equipment within the Chemistry Department.

This project combines the use of the 1-wire routines, serial routines, a P.I.D (Proportional, Integral, Derivative) calculation, ADC, and a interrupt driven burst mode heater control.

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Phase Controller for 2kW heater by Mike Pearce

From readme.txt: One of the projects I did need accurate control of a 2KW heater element ... with quite a bit of thought and some help with some math to work out "Even Power" steps for a sign wave, I sat down and wrote this simple, soft timed program that controls a single output and is set but 4 input pins. Uses 12C508. Note: this is an assembly language project, not a Hi-Tech C based project.

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Dear Shane Tolmie,

This site is great. It helped me a lot to start with c development on PIC.
Thank you for this great work.

Parag Panchal

Disco Light Controller by Mike Pearce

From readme.txt: I wanted to make up a simple disco light controller that went through a pre-programmed sequence, and I had not had HT-PIC C for long, so it was a good opportunity to have a play. Included are a couple of DOS programs that I used to generate the patterns and convert to an array ready to be pasted into the PIC's C file. I took this software one step further and had it output to the PC Parallel port so with a patch cable I could simulate the PIC's output on the actual circuit board I used, hence I was able to preview the lights outputs. Included is an image of the Lighting Box I built up.

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Dallas DS1821 three-pin digital thermostat by Mike Pearce

From readme.txt: The DALLAS DS1821 is a 3 pin digital thermostat that can have its trigger points programmed using the Dallas 1-wire interface. The need arose for this programmer when we had to replace the bi-metal thermostat controls from some fridges in the department for safety reasons. The DS1821 was the ideal replacement, the combination of small size, low operation voltage (3-5 volts) and operates to pre programmed settings that couldn't be changed unless you had a special programmer. Hence the birth of the DS1821 Programmer project. This project uses the 1-wire and I2C routines.The Turn On, Turn Off and Polarity values can be programmed using this code. There are 3 buttons, 'Menu', '+', and '-' to allow adjustments. The Data is displayed on a 4 digit I2C LCD controlled by a PCF8577 (Philips).

Archive includes Hi-Tech C source code, schematics, and more.

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Gym Timer by Mike Pearce

From readme.txt: For PIC12C509, this was a very simple timer and buzzer that I made for a client that wanted timer for doing gym circuits in his home gym. I made this one up on a piece of vera board, and it injects a signal into an audio line that was fed into an amplifier from his CD Player. This cut costs dramatically due to no extra amplifier/speakers needed. The time is set by the state of GP0,1,2,3 and is calculated by the binary value * 5 + 30 seconds. This allows the interval to be set from 30 seconds to 105 seconds in 5 second increments. This is only approximate!!GP5 was fed through a resistor and capacitor type set up into one channel of the audio and just does a short Buzz at the end of each interval.

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High Speed Pulse Generator (HSPG) by Mike Pearce

From readme.txt: I have included this code as an Example of using a 20x2 character LCD, I2C EEPROM and basic I/O Control, it also has a ascii to unsigned long function that I created to convert entered text into a useable number.The HSPG project is a specialized piece of hardware for accurately generating pulses on a rather large piece of equipment (it takes up a large room). This unit has a resolution of 20ns and a 24 bit counter (0 to approx. 0.335 sec in 20ns steps) and all the pulse outputs are fibre optic for noise reduction, earth loop elimination and speed. This is the only piece of equipment like it in the world that we know of, and hence it is restricted, so circuit diagrams will not be supplied. However, if you want to buy a complete unit (with updated firmware) ... not a problem if you have a spare US$10,000 ... but you still won't get the diagrams!!!

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LCD and Keypad project by Mike Pearce

From readme.txt: This project was for the first version of the High Speed Pulse Generator, but was scrapped due to technology restrictions of the time. But the board has been used for testing character LCDs and keypads, and does make a reasonable general purpose display and keypad type controller with a number of control lines available.

Hello Shane,

Congratulations on a truly excellent learning resource for PIC-C! I have learnt from your examples and refer many of our PIC customers to your site for additional design tips.

Please encourage contributions and grow the resource !

-Andrew Metcalfe
Field Applications Engineer,
Arrow Electronics

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Sample code from Mike Pearce

Miscellaneous code for reference, the projects above are a more complete and updated version of this archive.

  • Battery Charger for 8 Ni-Cad battery packs
  • Disco Light Driver For the PIC12C50x
  • Repeating Timer For Gym Circuits, switchable from 30 sec to 60 sec in 5 sec intervals
  • Program for using a PIC16C64 to control the heating/cooling for the PVC Reactor
  • Software to replace logic driving the Liquid Nitrogen Filler system, uses PIC12C508
  • Motor control software to drive UOC-MOTORCTRL-001 using PWM.
  • A program for the PIC12C50x to drive 4 solid state relays, uses RS232 and Dallas 1-wire system.
  • Program is a serial communication between Dallas Temp Probes PC and Phase Controller.
  • Basic code that turns the 16F84 into a EEPROM to get things up and running.

The entire archive is available. Download (213KB).

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Sample code from Ed Waugh (set C)


Sometimes it is useful to have access to a larger amount of non-volatile storage than is available onboard the PIC. A serial accessed eeprom can be the best way to do this but they are usually only available in sizes up to 512Kbits. The 24LC256 is a 256Kbit eeprom avaialble from microchip and is what these functions are designed to work with although they should work with any size and speed of eeprom with suitable modification of the loops. This is just the functions you need to get some code working and then drop these in.

The code has been tested on both a 16F876 using software and hardware I2C interfaces. Setting the pins to the hardware I2C port int the #use line at the top of the code enables the hardware I2C.

Basic read and write byte functions are provided as well as a set of functions for a contiguous read (by Tom Cook) that allows faster read out of a stream of data. There is also a function to write a string of any length to the eeprom. They should all be fairly self explanatory.

EEPROM source in CCS C

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MMC card

For applications where more storage is required I would definately reccomend MultiMediaCards (some times called SanDisk (SD) flash). The built in SPI interface only requires four data lines and they are available in sizes of up to 256MByte (at the moment). There are a few little quirks in making the cards work with a PIC but these are hopefully all sorted out within the code. The code is set to use the hardware SPI pins on the 16F876 and I haven't tried it any other way.

The MMC card has quite a large block size for writing, I think at the moment it is at least 512Bytes although I think I saw something about a new version of the specifcation that is more flexible. But at the moment this means that you need to buffer 512Bytes and write them all in one go, the eeprom code (above) is ideal for this. The write_block function just writes the lowest 512Bytes from the eeprom to the MMC. The same is true when reading the card and in my current application I only need to read the data to a PC so the read_block function just outputs every byte to RS232 although it wouldn't be hard to insert some processing or pass each byte to whatever function you wanted. This is just the functions you need to get some code working and then drop these in.

MMC source in CCS C

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C code samples for dsPIC by Mike Pearce (set D)

"Hello World" for dsPIC30F3011 on a KPIC-2840P prototyping board

From readme.txt: All my samples will be written for the dsPIC30F3011 40 pin DIP package that can work (with minor mods) on a KPIC-2840P prototyping board (available from Compiled with the C30 evaluation version of the C compiler from

This project is a simple "Hello World" sent out the serial port. Shows quick setup of the UART for TX only.

C source for Microchip C30 compiler for Hello World

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RC Pulse for dsPIC30F3011 on a KPIC-2840P prototyping board

From readme.txt: All my samples will be written for the dsPIC30F3011 40 pin DIP package that can work (with minor mods) on a KPIC-2840P prototyping board (available from Compiled with the C30 evaluation version of the C compiler from

RCPulse generates the 1 to 2ms pulse required for remote control servo control. Demonstrates the use of Timer and interrupts. Currently writing a multichannel version for a project. Compiled with the C30 evaluation version of the C compiler from

C source for Microchip C30 compiler for RC Pulse

Samsung KS0713 Graphical LCD Driver for Microchip PIC24 and dsPIC33 Microcontrolers

From readme.txt: Make sure you have the latest MPLAB and MPLAB C30 programs from before proceeding.

Original hardware obtained from Mike Pearce from

Click to enlarge

1. Create a new project.

2. Select PIC24 or dsPIC processor.

3. Select MPLAB-C30 compiler.

4. Add the following files and select "copy to project folder".

glcdtest.c (for demo code - otherwise your main c file )
pXXxxxx.gld (The gld file specifically for your micro-controller)
(Found in c:\Program files\Microchip\Mplab C30\Support\Gld\)

5. Once setup has completed open the glcd.h file for editing.
Change the I/O LAT, PORT, TRIS settings to match your design.
Change frequecy to match your design.
Change display resolution to match your LCD.
Save your changes.

6. Open main.c for editing (This is just a basic framework).

Fill in the gaps with the rest of your program.
Make sure any analog input ports that have been used for the LCD are set up as digital I/O.

7. Compile and hopefully it works.

C project for Microchip C30 compiler for Samsung KS0713 Graphical LCD Driver.

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C code samples for PIC18F4550 from John Leung (set E)

PIC18LF4550 with LCD and Temperature Sensor

"Attached is an example project to display real-time ambient temperature and relative humidity from SHT10 digital sensor on a 65k 1.8" color display. The microcontroller was PIC18LF4550. The result is shown in the jpeg file as well. All code with heavy comment."

Compiler: C18 compiler v2.40
Comaptible with SHT10 digital temperature and humidity sensor.
Compatible with CM50012ACT6 65k color Graphical LCD Display Driver (HYVIX HDC1600 controller).
Original hardware obtained from

Temperature sensor with LCD for PIC18LF4550.

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Joystick Demo

"Attached please find another application for using joystick commonly found in game pad, mobile phones, etc. It is nothing more than individual tactile keys. There is a .pdf explaining the source code as well. Working on a dev board for PIC24 series. It will come with a 2.2" TFT color LCD. Designed for the C18 compiler."

Original hardware obtained from

PIC sample project with JoyStick and I/O handling. Note: zip file includes documentation in .pdf format.

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MiniBasic Source Code in C (set F)

MiniBasic example peripheral source code in C

MniBasic is a full basic interpreteter for the PIC18, PIC24, and PIC32. It is written in C. By examining the source code, you can work out how to use almost any peripheral on the PIC18, PIC24 or PIC32. Example peripheral source code includes, but is not limited to, RS232, PWM, timers, LCD, port control, SPI, I2C, ethernet (under development), etc.


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Source Code from Regulus Berdin (set G)

Interrupt Driven Serial Routines with Circular FIFO for PIC16x Micro

This is another routine that I want to share. This is the interrupt driven serial routine with circular FIFO for any PIC16x micro with a hardware UART. Compiled with Hi-Tech C. Since this is unbuffered, so I added a software FIFO. The FIFO management is quite lean and fast but required the size of the buffer to be power of 2 (2^x). This is because FIFO roll-over uses bit-wise AND of (buffer_size - 1). This reduces code size due to that no more conditionals to test pointers overflowing the buffer.

Interrupt driven serial routine with circular FIFO for PIC micro.

Tiny Threads - Tiny Multitasking Threads for Microcontrollers

For the efficiency and performance conscious C programmers, here is my tiny cooperative multitasking engine.

by Regulus Berdin

  • Maximum 254 lines per thread.
  • Thread context switching will not work within a switch block.

tthread.h. Header file for Tiny Threads. This is the only file needed to use Tiny Threads. Sample application using tthread. Compiles with PICC compiler from

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Source code from Shane Tolmie (set H)

InnoSetupAV v1.00, a sample installer script for any Windows based support programs for any embedded work.

UVa Tutorial

You can easily rank your programming aptitude compared to others - over 80,000 others, to be precise.

Read more on the UVa Online Judge tutorial.

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The Dot Factory: An LCD Font and Image Generator

From The Dot Factory is a small, GPL, open source tool intended to generate the required C language information to store many fonts and images, as efficiently as possible, on a microcontroller. These fonts are then uploaded via the LCD driver (see the Drivers and Modules page for a few) to the actual dot matrix LCD. Compatible with numerous PIC micros, more micros can easily be added by writing a simple driver.

Read more.

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Embedded PIC Programmer

From Hi Shane, I'm the author of The Dot Factory, the free LCD font generator you so gracefully link to on microchipc. I was recently contracted to implement lpicp, a PIC programmer that works on embedded Linux platforms. It allows any embedded platform running Linux to effectively become a PIC programmer. I haven't seen such an implementation before so I released it as GPL, for anyone to use or reference.

If you feel it is relevant for microchipc, please feel free to link to the project page:

Read more.

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Portable LCD driver

From Pallav Aggarwal:

Following link contains code for Character LCD interface Driver for 16x2 Size (8bit/4bit configurable), this is fully portable code for any MCU.

Requesting you to please add my code for the benefit of all engineers and students.

If you feel it is relevant for microchipc, please feel free to link to the project page:

Portable LCD driver.

Read more.


Published in response to an email sent the admin at MicrochipC. This website also has a good range of other sample code, its worth checking out.

Dear All,

I just published a new version of my "toy" RTOS in my personal pages at PICList. Just it is not a "toy" anymore, it is really useful and I'm using it already in new projects.

For now the ports for dsPIC/PIC24 and PIC32MX are already working, but I published only the PIC32MX port because it is already tested.

The link is

My main page is

I plan to port it also to ARM Cortex-M3 and M4 because I use Atmel's SAM3 and SAM4 devices, but those ports may take some time to be finished.

My original RTOS was just a proof-of-concept cooperative RTOS for
PIC16F, but could be used in some simple applications.

My main motivation to rewrite it for bigger MCUs was that FreeRTOS uses too much memory and it doesn't fit even in some PIC32MX devices's (PIC32MX210F016B) RAM or FLASH. My RTOS uses just a fraction of the memory needed by FreeRTOS and I expect it to be somewhat faster.

The sample application which has six tasks, each one with a 256-bytes stack, when compiled with optimization level -O3 uses just 3685 instruction words and 2956 bytes of RAM. It fits easily in a PIC32MX210F016B.

I know that it cannot compete with FreeRTOS in general, but for some simple applications or very constrained devices it may fit while FreeRTOS won't.

Comments are welcome.

Best regards,










This site is non-profit. Ad revenue almost covers hosting costs.

We welcome any suggesions or comments! Send them to Shane Tolmie on This site is a completely separate site to, and is maintained independently of Microchip Ltd., manufacturers of the PIC micro. All code on this site is free for non-commercial use, unless stated otherwise. Commercial use normally free, however, it is prohibited without contacting for permission. All content on this site created by Shane Tolmie is copyrighted by Shane Tolmie 1999-2009. Click to advertise on this website - $29.90 for a banner ad which will reach 55,000 user sessions per month. One months free trial!