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Avr-Microcontrollers-in-Linux-Howto
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Avr-Microcontrollers-in-Linux-Howto
Revision History
Revision 44 2009-04-20 17:13:07 Revised by: jdd
obfuscate e-mail at the author demand
Revision 43 2009-03-29 20:49:12 Revised by: ranjeeth
Revision 42 2009-03-29 20:45:09 Revised by: jdd
reverting after publication
Revision 41 2009-03-29 20:41:59 Revised by: jdd
edit to export docbook
Revision 40 2009-03-28 21:07:57 Revised by: RickMoen
Adjust style of mailto link to author's original preference.
Revision 39 2009-03-28 21:05:45 Revised by: RickMoen
Revert e-mail obfuscation, supply some missing punctuation, [re-]fix
capitalisation, fix and clarify new run-on sentence.
Revision 38 2009-03-23 18:21:24 Revised by: ranjeeth
Revision 37 2009-03-23 18:19:51 Revised by: ranjeeth
Revision 36 2009-03-23 17:20:32 Revised by: ranjeeth
Revision 35 2009-03-23 17:19:47 Revised by: ranjeeth
Revision 34 2009-03-23 10:26:00 Revised by: jdd
publishing tests
Revision 33 2009-03-23 10:25:06 Revised by: jdd
Revision 32 2009-03-23 10:24:24 Revised by: jdd
use of macro to obfuscate e-mail
Revision 31 2009-03-23 10:11:47 Revised by: jdd
change was only to export docbook without admonitions
Revision 30 2009-03-23 10:09:15 Revised by: jdd
Revision 29 2009-03-23 10:05:07 Revised by: jdd
Revision 28 2009-03-23 09:58:40 Revised by: jdd
adding the wiki as link
Revision 27 2009-03-23 09:53:28 Revised by: RickMoen
Insert needed space characters into "pin9", "pin10", "pin25" constructs
Revision 26 2009-03-23 09:49:05 Revised by: RickMoen
Make markup of all the software items mentioned be consistent
Revision 25 2009-03-23 09:43:40 Revised by: RickMoen
Remove a couple of stray commas.
Revision 24 2009-03-23 09:41:30 Revised by: RickMoen
Polishing up a few last bits of punctuation
Revision 23 2009-03-23 04:11:31 Revised by: ranjeeth
Revision 22 2009-03-23 04:10:34 Revised by: ranjeeth
Revision 21 2009-03-23 04:09:07 Revised by: ranjeeth
Revision 20 2009-03-17 16:20:27 Revised by: ranjeeth
Revision 19 2009-03-17 16:18:33 Revised by: ranjeeth
Revision 18 2009-03-16 19:10:30 Revised by: RickMoen
Fix hyperlink, fix English diction of new sentence.
Revision 17 2009-03-16 18:50:19 Revised by: ranjeeth
Revision 16 2009-03-16 11:36:49 Revised by: RickMoen
A couple of punctuation nits
Revision 15 2009-03-16 11:21:14 Revised by: RickMoen
Corrected numerous run-on sentences, punctuation and grammar errors, and
questionable idiom.
Revision 14 2009-03-15 10:27:24 Revised by: BordenRhodes
Cleaned up basic grammar and spelling
Revision 13 2009-03-15 09:52:41 Revised by: jdd
Revision 12 2009-03-15 09:51:37 Revised by: jdd
add link to the manual of avr-libc
Revision 11 2009-03-14 21:47:18 Revised by: jdd
end of basic conversion
Revision 10 2009-03-14 21:40:18 Revised by: jdd
Revision 9 2009-03-14 21:39:26 Revised by: jdd
Revision 8 2009-03-14 21:33:04 Revised by: jdd
add the image
Revision 7 2009-03-14 21:27:59 Revised by: jdd
Revision 6 2009-03-14 21:26:48 Revised by: jdd
Revision 5 2009-03-14 21:25:13 Revised by: jdd
Firts step - conversion fro html by jdd and basic format edition
Revision 4 2009-03-14 21:22:37 Revised by: jdd
Revision 3 2009-03-14 21:18:25 Revised by: jdd
Revision 2 2009-03-14 21:13:09 Revised by: jdd
Revision 1 2009-03-14 21:10:33 Revised by: jdd
------------------------------------------------------------------------
Table of Contents
1. HOWTO
2. AVR Microcontrollers in Linux HOWTO
2.1. Licence
2.2. What Is a Microcontroller?
2.3. Software Required
2.4. Hello World
2.5. Author
2.6. Last version
1. HOWTO
AVR Microcontrollers in Linux HOWTO, Copyright (C) 2009 Ranjeeth p t
(ranjeeth_gecmail[at]yahoo[dot]com)
This HOWTO is for readers wishing to program an AVR microcontroller
using a GNU/Linux machine. For burning your code, we will be using a
parallel port. You may need other electronics components (like a few
resistors, capacitors, parallel port connector, etc.), which can be
bought from any electronics shop.
------------------------------------------------------------------------
2. AVR Microcontrollers in Linux HOWTO
2.1. Licence
Permission is granted to copy, distribute, and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.2, or any later version published by the Free Software
Foundation; with no Invariant Sections, no Front-Cover Texts, and
no Back-Cover Texts. A copy of the license is included in the
section entitled "GNU Free Documentation License".
[http://wiki.tldp.org/LdpWikiDefaultLicence#GNUFreeDocumentationLicense]
GNU Free Documentation License
------------------------------------------------------------------------
2.2. What Is a Microcontroller?
A microcontroller is a single-chip computer. It has internal RAM, ROM,
timers, counters, interrupt circuitry, I/O ports, analog comparators,
serial USARTs, analog to digital converters, watchdog timers, and a RISC
architecture. When you are using a microprocessor, you cannot program it
alone. You need other components, like RAM, ROM, timers, etc. For
programming, you should know its architecture thoroughly: You must read
the datasheet for your microcontroller.
------------------------------------------------------------------------
2.3. Software Required
binutils: Tools like the assembler, linker, etc.
gcc-avr: The GNU C compiler (cross-compiler for avr).
avr-libc: Package for the AVR C library, containing many utility
functions.
uisp: A Micro In-System Programmer for Atmel's AVR MCUs (for burning
code to MCUs' memory).
The following Atmel microcontrollers are supported by avr-gcc in Linux:
at90s Type Devices
at90s2313, at90s2323, at90s2333, at90s2343, at90s4414, at90s4433,
at90s4434, at90s8515, at90s8515, at90s8515, at90s8535, at90s1200.
atmega Type Devices
atmega103, atmega603, atmega8, atmega48, atmega88, atmega8515,
atmega8535, atmega16, atmega161, atmega162, atmega163, atmega165,
atmega168, atmega169, atmega32, atmega323, atmega325, atmega3250,
atmega64, atmega645, atmega6450, atmega128.
attiny Type Devices
attiny22, attiny26, attiny26, attiny13, attiny13, attiny13, attiny13,
attiny2313, attiny11, attiny12, attiny15, attiny28.
Other AVR Devices
avr2, at90c8534, at86rf401, avr3, at43usb320, at43usb355, at76c711,
avr4, avr5, at90can128, at94k, avr1.
binutils: Programs to manipulate binary and object files that may have
been created for Atmel's AVR architecture. This package is primarily for
AVR developers and cross-compilers.
gcc-avr: The GNU C compiler, a fairly portable optimising compiler that
supports multiple languages. This package includes C language support.
avr-libc: Standard library used for developing C programs for Atmel AVR
microcontrollers. This package contains static libraries, as well as
needed header files.
uisp: Utility to program AVR chips with object code created by gcc-avr.
It supports in-system programming.
You download the above packages untar, configure, and install it. If you
are using Debian or Ubuntu, these packages are available in your
distribution: Install them using apt or synaptic package manager.
------------------------------------------------------------------------
2.4. Hello World
We are writing hello world for the atmega8 microcontroller, which has a
28-pin, 8-bit, RISC architecture.
Before proceeding, have a look at
[http://www.nongnu.org/avr-libc/user-manual/] this manual about
__avr-libc__, which will help you program better, and understand. Also,
refer to the datasheets for the various AVR microcontrollers.
Here is our first program:
/* ledblink.c, an LED blinking program */
#include<avr/io.h>
#include<util/delay.h>
void sleep(uint8_t millisec)
{
while(millisec)
{
_delay_ms(1);/* 1 ms delay */
millisec--;
}
}
main()
{
DDRC |=1<<PC2; /* PC2 will now be the output pin */
while(1)
{
PORTC &= ~(1<<PC2);/* PC2 LOW */
sleep(100);/* 100 ms delay */
PORTC |=(1<<PC2); /* PC2 HIGH */
sleep(100);/* 100 ms delay */
}
}
------------------------------------------------------------------------
2.4.1. Code Explanation
The GNU C compiler for the Atmel family identifies all functional units
within the microcontroller with meaningful names. Thus, writing
`PORTC=0xff' will result in the compiler generating machine code that
writes 0xff to I/O port C, which will set all port C pins to logic high.
Because ports are bidirectional, we must decide whether each pin should
act as input or output. If the i'th bit of a register called DDRC (data
direction register C) is 1, then the i'th pin of PORTC's i'th pin will
be an output. Otherwise, it will act as an input pin. (Note that pin and
bit numbers start at zero.) To make an LED blink, you have to make a pin
high, then low. (Here, we use PORTC's 2^nd port. That is, PC2 will be
the 25^th pin.) There should be a delay between the two. This is what
the rest of the code does. For the delay, we use built-in function
_delay_ms(1), which causes a 1 ms delay.
------------------------------------------------------------------------
2.4.2. Compilation
avr-gcc -mmcu=atmega8 Os ledblink.c o ledblink.o
which will result in object file ledblink.o. Now, we will covert it to
hex file, suitable for burning to the microcontroller's memory.
avr-objcopy -j .text -j .data -O ihex ledblink.o ledblink.hex
We are converting it to a hex file because, for burning the code to
atmega8, we will use uisp, whose input file must be a .hex file.
Notice that you can less the ledblink.hex file.
:1000000012C02BC02AC029C028C027C026C025C0C6
:1000100024C023C022C021C020C01FC01EC01DC0DC
:100020001CC01BC01AC011241FBECFE5D4E0DEBF28
:10003000CDBF10E0A0E6B0E0EAE8F0E002C0059035
:100040000D92A036B107D9F710E0A0E6B0E001C0EC
:100050001D92A036B107E1F70CC0D2CF282FE4ECF7
:10006000F9E004C0CF010197F1F721502223D1F725
:100070000895CFE5D4E0DEBFCDBFA29AAA9884E66A
:0A008000EDDFAA9A84E6EADFF9CF6B
:00000001FF
------------------------------------------------------------------------
2.4.3. Burning the Code
2.4.3.1. Hardware
We will be using the parallel port for burning. First, we have to
develop a burning circuit for it.
This is the circuit for the atmega8 microcontroller. Pin 9 & pin 10 are
connected by a 4 MHz crystal oscillator, which is the external clock.
The bottom right connector is for a parallel port.
If you are using any other microcontroller, as mentioned above, you
should change accordingly. }}}
You should watch for RESET,XTAL1,XTAL2,SCK,MISO,MOSI pins, and connect.
------------------------------------------------------------------------
2.4.3.2. Software
Now, we will burn ledblink.hex to the microcontroller.
uisp -dprog=dapa -dlpt=0x378
You should get message Atmega8 Found.
dprog is the programming method specifier, which in this case is dapa,
i.e., Direct AVR Parallel Access. dlpt is for the parallel device
setting, which is 0x378, the parallel port's device address.
uisp -dprog=dapa -dlpt=0x378 --erase
Will erase the microcontroller's code.
uisp -dprog=dapa -dlpt=0x378 --upload if=ledblink.hex
Will upload the Input File ledblink.hex
Notice that you can see the LED at pin 25 blinking.
------------------------------------------------------------------------
2.5. Author
Comments to: [mailto:ranjeeth_gecmail[at]yahoo[dot]com]
mailto:ranjeeth_gecmail[at]yahoo[dot]com
[http://ranjeethpt.wordpress.com] Ranjeeth Weblog
Govt Engg College Sreekrishnapuram,
Palakkad,Kerala India.
------------------------------------------------------------------------
2.6. Last version
You may find the last up-to-date version of this HOWTO
[http://wiki.tldp.org/Avr-Microcontrollers-in-Linux-Howto] on the LDP
wiki.