AVR
This article applies to Arduino boards only.
See also: Multiplatform Programming Guide
General information
The FPC-AVR port is currently experimental and non working. It uses the GCC AVR tool chain and will be compatible with GCC regarding calling conventions etc.
Implementation details
FPC considers AVR being a 16 bit CPU. So the type tregister actually describes a register pair being the second register implicitly named.
Building Cross compiler
There are some requirements, you should know about
- You should use the latest Free Pascal sources as there is the most recent support for more controllers.
- Binutils for avr target
- Atmel provides bintuils binaries for Linux, Mac OS X and Windows. Please visit http://distribute.atmel.no/tools/opensource/Atmel-AVR-GNU-Toolchain/3.5.0/ (registration required) and follow the appropriate link for your operating system.
- On Linux host, you may either install bintuils for avr target from your distribution or use also the binaries provided by Atmel.
- You may also use the bintuils distributed with the Arduino IDE; on Windows they are installed to e.g. C:\Program Files (x86)\Arduino\hardware\tools\avr\avr\bin
- Keep in mind, the Free Pacal Compiler will search for e.g. avr-embedded-as. So you must either rename the binary files, create symlinks (on Linux only) or adjust command line switch -XP<prefix> for FPC.
- You may need to set FPC's command line switch -FD<directory with binutils>
- Latest stable Free Pascal Compiler
Then you can build your cross compiler. Please choose SUBARCH according to your Arduino board / AVR microprocessor.
make buildbase installbase CPU_TARGET=avr OS_TARGET=embedded SUBARCH=avr5 CROSSINSTALL=1 INSTALL_PREFIX=~/fpc NOGDB=1 PP=/usr/bin/fpc CROSSBINDIR=/usr/avr/bin
You may also set the bintuils prefix for this (equivialent to -XP switch)
make buildbase installbase CPU_TARGET=avr OS_TARGET=embedded SUBARCH=avr5 CROSSINSTALL=1 INSTALL_PREFIX=~/fpc NOGDB=1 PP=/usr/bin/fpc CROSSBINDIR=/usr/avr/bin BINUTILSPREFIX=avr-
Subarchitecture
The operating system target embedded requires you to specify a aubarchicture when building a cross compiler. The subarchitectures are compatible to the ones used by gcc.
There is a list at: http://www.nongnu.org/avr-libc/user-manual/using_tools.html
Resources
- General information: http://en.wikipedia.org/wiki/Atmel_AVR
- Atmel site: http://www.atmel.com/products/microcontrollers/avr/default.aspx
- Calling conventions: http://www.nongnu.org/avr-libc/user-manual/FAQ.html#faq_reg_usage
- Discussion on: http://www.lazarusforum.de/viewtopic.php?f=9&t=5444&start=30 (German)