fpc-avr

A collection of Free Pascal AVR microcontroller code snippets, examples and libraries.

Structure

bin

A Linux-64 bit compiled gdb 8.0 for avr, includes patch for debugging program memory. Not really needed anymore, since fpdebug nowadays supports AVR debugging.

src folder

examples

Name	Description
HX711	Reads the value from a HX711 load cell amplifier over SPI.
IRCcapture	A timer based method for capturing infrared remote control signal pulse timings.
adc4809	A simple demonstration of using the analog to digital converter of the atmega4809 (avrxmega3).
blink1	A simple blink example using busy delay functions.
blink2	A simple timer interrupt driven blink example.
blink4809	A simple blink example using busy delays to test the megaAVR0 series code.
blinktiny10	A simple blink example using a timer interrupt, for the attiny10 controller.
blinktiny104	A simple blink example using a timer interrupt, for the attiny104 controller.
blinktiny15	A simple blink example using a timer interrupt, for the attiny15 controller which doesn't have any RAM.
dht_example	Reads a DHT11/21/22 or compatible humidity and temperature sensor and write values to serial.
dumptiny104flash	A program to dump flash contents to serial. Written to investigate a potential hardware bug
hello_world	Demonstrates how to redirect console I/O to UART.
i2c	Reads the time from a DS1307 real time clock over i2c.
i2c_BMP	Simple program to read values from a BMP085 or BMP180 pressure sensor over I2C.
i2cscan	An i2c address scanner.
i2cslave	A simle i2c slave demonstration.
intmath	Testing of assembler versions of integer division algorithms in the integermath library.
lcd1	A simple sliding text example for HD44780 compatible character LCDs.
lcd1_i2c	A simple sliding text example for HD44780 compatible character LCDs using an i2c backpack.
lcd2	Show bitmap and sliding text on PCD8544 compatible LCD.
lcd2-progmem	Show bitmap and sliding text on PCD8544 compatible LCD. Also shows how to load a glyph from flash memory.
light_tracker	A simple fun project that uses a light sensor mounted on a servo driven pan & tilt base to track a light source.
mpu6050-pan-tilt	A demonstration of driving a pan & tilt servo setup with an MPU6050 6 axis inertial measurement unit.
mpu6050	Reads the gyroscope and accelerometer values of an MPU6050 inertial measurement unit and write the values over serial.
ringbuffer	Demonstrates how to use the spsc_ringbuffer library. spsc_ringbuffer is a ring buffer which writes and reads, in such a way that mutual exclusion is not required (assumes one reader & one writer, hence the SPSC name a.k.a Single Producer / Single Consumer)
simavrtest	Demonstrates how to pass information to simavr using .mmcu section.
softserial	A simple demonstration of software serial typically for attiny controllers without USART.
sound	A sound (noise) generator using simple formulas. Demonstrated on an attiny10.
uart1	A simple serial test that reads a character and echos its ordinal value.
uart4809	A simple test written mostly to figure out how to read a button press, generate timer interrupts and send data over serial on the atmega4809.

scripts

A collection of scripts useful for debugging.

tests

This folder contains test cases for various changes to the rtl, bugs in the compiler, etc.

Compiling

AVR cross compiler

Refer to Building cross-compiler for tips.

Compiling examples

An easy way to compile an example is to open the lazarus project file in the lazarus subfolder in the example. This will open the example in Lazarus and all required options to compile the example will be configured, except the path to the AVR cross compiler. To configure Lazarus to use the cross compiler for the project, open Project Options (ctrl + shift + F11), go to Compiler Commands and enter path to cross compiler executable.

Another way that doesn't require Lazarus is to use a compile script, for example on Linux:

#!/bin/sh
~/fpc/3.3.1/compiler/ppcrossavr -Tembedded -Wpatmega328p -Cpavr5 -Pavr -O3 -g -al -XPavr- -Fu"../../library" -Sm -dF_CPU:=16000000 $1

This script needs to be executed from the base folder of an example, to ensure the relative path to the library is valid. The name of the example project should be passed to the script as a parameter e.g. sh compile.sh blink1.pp.

An equivalent batch file for Windows could be as follows (untested):

[substitute your path to fpc compiler folder here]\ppcrossavr.exe -Tembedded -Wpatmega328p -Cpavr5 -Pavr -O3 -g -al -XPavr- -Fu"..\..\library" -Sm -dF_CPU:=16000000 $1

Explanation of required and useful compiler options:

• -Sm - enable macro support, required to pass the -dF_CPU as command line parameter to the compiler.
• -dF_CPU - the clock frequency of the target mcu (by convention the F_CPU define is expected wherever the mcu clock speed is required.
• -Fu"../../library" - path to library folder.
• -O3 - optional optimization flag, usually results in smaller code (which is a good thing).
• -al - optional, list source code lines in assmebler file