AVR web server with remote equipment control, temperature sensors and temperature graphs

!! READ THIS FIRST !!
---------------------
The mac address has to be unique within your own network.
If you connect more than one board to the same LAN
you will need to change the mac address to something else.
Edit the file main.c and change the last digit in this line:

static uint8_t mymac[6] = {0x54,0x55,0x58,0x10,0x00,0x29};

It does not matter to what value you change it as long as
there is no other ethernet board with the same value on your
lan. Your neighbor could re-use the same address.

Check the file "Makefile" and make sure the MCU is set correctly:

MCU=atmega168
DUDECPUTYPE=m168
or
MCU=atmega328p
DUDECPUTYPE=m328p

More information about Makefiles can be found at:
http://tuxgraphics.org/electronics/200912/makefiles.shtml

This software has a fixed IP address which is set at compile time in 
file main.c:
static uint8_t myip[4] = {10,0,0,29};

myip must be a free address from the address range in your network.

There is a range of private addresses (not routed on the public internet)
which you can use:
Netmask          Network Addresses
255.0.0.0         10.0.0.0 - 10.255.255.255
255.255.0.0       172.16.0.0 - 172.31.255.255
255.255.255.0     192.168.0.0 - 192.168.255.255

Example: you wlan router might have 192.168.1.1, your PC might have
192.168.1.2. This means you could e.g use 192.168.1.10 and leave some
room for more PCs. If you use DHCP then make sure that the address it not
double allocated (exclude it from the DHCP range).

You need an avr-gcc development environment in order to compile this.

To change the state of the switch or to see the debug page (if enabled in
via DEBUG_SENSORS in main.c) you need a password.
The default password is: secret
It is defined in main.c on this line:
static char password[]="secret";

To compile the software use the command:
make

Note: windows users may use and modify the supplied winmake.bat to setup the
environment correctly.

The command
make load

will execute the avrdude command to load the software.
E.g something like: 
   avrdude -p m168 -c stk500v2 -e -U flash:w:main.hex

! Note: your programmer might interfere with the enc28j60! For the avrusb500
! with 30cm cable you can normally leave the cable on. For all other programmers
! it is however saver to remove the programmer cable and power down/up the device.
! This is because the SPI interface is used for loading of the software and 
! communication to the enc28j60.

To see a list of all possible build targets run the command:
make help

Selecting the right clock source
--------------------------------
Tuxgraphics hardware sold as of march 2007 is prepared to use the clock
signal from the enc28j60. To use this you need to change the 
low fuse byte once from 0x62 to 0x60:
avrdude -p m168 -c stk500v2 -u -v -U lfuse:w:0x60:m

Note: first load the code then change the fuse.

or just type in your Linux shell:
make fuse

After programming the fuse settings of atmega168 and atmega88 should be:
 low fuse:  0x60
 high fuse: 0xdf
 ext. fuse: 0x01

For the atmega328p the hfuse and efuse bytes look slightly different.
The idea is however the same. Just change the lfuse from factory default
to 0x60. The fuse settings of the atmega328 are after programming:
 lfuse reads as 0x60
 hfuse reads as 0xD9
 efuse reads as 0x07

details of the lfuse bits:
  CKDIV8 = 0
  CKOUT  = 1
  SUT1   = 1
  SUT0   = 0
  CKSEL3 = 0
  CKSEL2 = 0
  CKSEL1 = 0
  CKSEL0 = 0

If you are unsure what the current fuse setting are on the atmega
then you can read the fuse settings with a command like: 
          avrdude -p m168 -c stk500v2 -v -q
The result should be this (default factory settings for atmega168):
          avrdude: safemode: lfuse reads as 62
          avrdude: safemode: hfuse reads as DF
          avrdude: safemode: efuse reads as 1

The result should be this (default factory settings for atmega328p):
          avrdude: safemode: lfuse reads as 62
          avrdude: safemode: hfuse reads as D9
          avrdude: safemode: efuse reads as 7

For a new virgin microcontroller: First load the code then change the fuse
--------------------------------------------------------------------------
The atmega gets it's clock from the enc28j60 once the fuse is changed.
The enc28j60 can however supply several clock speeds and the software
in the atmega tells the enc28j60 which speed to use. If you do
not load the atmega code first then enc28j60 will not get any commands
and supply a very low clock speed. 
This can mean that you can not program the atmega at normal
speeds. In other words if you did it by mistake the wrong way round then
add the -B option with 3 (or higher values) as argument to lower the programmer
speed:

avrdude  -B 3 -p m168 -c stk500v2 -e -U flash:w:main.hex

Note that this only relevant the very first time you load the ethernet software.
After that the microcontroller will always set at startup the right clock speed
in the enc28j60 chip. You don't have to worry about it.

Note also that the fuse is changed only once. If you update the software
at a later point in time then you do NOT need worry about it.

Compiling on non-Unix systems
-----------------------------
Please use the provided Makefile !!!

It will also work under Windows.

Take also a look at the supplied winmake.bat file. This bat script
might be needed to set the environment correctly.

Edit the Makefile to make the needed adjustments at the top
of the file.

More information about Makefiles can be found at:
http://tuxgraphics.org/electronics/200912/makefiles.shtml

Using the web server
--------------------
Point your web browser to
http://10.0.0.29   (or what ever IP address you have given your hardware)

You should see a page like this:

------------------------------------------
[refresh] [switch] [graph] [dbg sensor]

Temperature

sensor 0: 23.6'C [74'F]
sensor 1: 22.8'C [73'F]
------------------------------------------

The temperature history graphs use javascript. You need a javascript
capable web browser to see them. Even web browsers inside mobile phone
are these days javascript capable.

Authors/Copyright
-----------------
Most of the software was written by Guido Socher.
The ds18x20 and onewire code is taken from 
http://www.siwawi.arubi.uni-kl.de/avr_projects/tempsensor/index.html
It was written by Martin Thomas and based on code of Peter Dannegger,
Colin O'Flynn and others.

Guido Socher modified the ds18x20 and one-wire code to fit to this
application.

The enc28j60 driver is based on code from Pascal Stang and updated
by Guido Socher.

All code is copyright GPL V2.

Revision history
----------------
2009-06-08: version 0.2 -- first public version
2009-06-12: version 0.3 -- - amplify differences in graph height more
                           - correct small depenency error in Makefile
                           - add favicon.ico 
2009-09-20: version 0.4 -- - prevent blocking of eeprom routines
                           - initialize graphdat
                           - security length check after GET
                           - minimum graph width
2009-12-30: version 0.5 -- - improvements to the makefile