Tuxgraphics Digital DC Power Supply Unit
Software for the version 3 hardware.
Compiling the software and programming
the microcontroller (atmega8 or atmega8a):
==========================================
1) edit and adapt the file hardware_settings.h
(calibration and selection of the right hardware type).
You can as well just copy one of the pre-set versions
on top of hardware_settings.h.
Example: cp hardware_settings.h-22V hardware_settings.h
2) load and compile:
make
make load
3) set the fuse bytes to 8MHz internal with BOD:
make fuse
This should result in the following settings:
Device signature = 0x1e9307
lfuse reads as A4
hfuse reads as D9
Fuse Low Byte details
BODLEVEL Brown out detector trigger level = 1
BODEN Brown out detector, 0=enable = 0
SUT1 Select start-up time = 1
SUT0 Select start-up time = 0
CKSEL3 Select Clock source = 0
CKSEL2 Select Clock source = 1
CKSEL1 Select Clock source = 0
CKSEL0 Select Clock source = 0
The "make fuse" needs to be done only once
unless you change the Atmega8/Atmega8a chip. make/make load
need to be repeated everytime you change something
in the software (e.g update of hardware_settings.h).
The poweresupply must be powered up during programming
but nothing should be connected on the output. Make
sure that you do not accidently press any button
during the programming (while loading the software into the uC).
Compile under windows
=====================
Please use the provided Makefile.
There are as well 3 batch files which you can use
to run the makefile. To use them edit them and change
the path as per your avr-gcc installation on your PC.
After that run them by double-clicking on them in the
file manager.
winmake.bat -- comile, this is mandatory to use
winclean.bat -- delete all files generated during compilation
winload.bat -- load software using avrdude, may also use
some other means of loading the softare. In that
case you do not need to use this batch file.
winsetfuse.bat -- set fuse bytes using avrdude. You may as well use
some other means of changing the fuse bytes. In that
case you do not need to use this batch file.
Calibration
===========
To calibrate the display edit the file hardware_settings.h
Here you can change also the settings between the 30V and the 22V version.
In general you should only need to change
U_DIVIDER and I_RESISTOR by very small amounts.
Overview
========
This is the software for the tuxgraphics.org electronic digital DC power supply.
A microncontroller controlled bench DC power supply unit.
All of the control logic is implemented in software. This
saves a lot of parts compared to conventional lab-power
supplies and means it is cheaper, easier to build and
offers more functionallity.
Note however that this means also that the short circuit
protection is implemented in software. Be careful when
you change something in the software. If the microcontroller
is not running properly due to a software fault then there
might not be any short circuit protection.
The software is prepared for 2 versions:
- 0-22V 0-2.5A
- 0-30V 0-2A
If you want to build a version that has a smaller output
range than any of the two version then you can just
modify the file hardware_settings.h.
Remote control from your PC
===========================
The unit can be controlled remotely from a computer using
a USB serial interface. An add-on card is available from
http://shop.tuxgraphics.org which offers galvanic separation
such that you can use this power supply relative to
any reference point (e.g build two power supplies and use
one as negative and one as positive power supply).
Terminal settings for remote control via your computer
======================================================
You can e.g use putty under windows
http://www.chiark.greenend.org.uk/~sgtatham/putty/
Putty supports as serial connections. The other common
option under windows is HyperTerminal but it is more complicated
to use than putty.
For Linux I can recommend picocom
http://code.google.com/p/picocom/
(use command picocom -l -b 9600 /dev/ttyUSB0)
Another good serial terminal for linux is gtkterm
http://www.jls-info.com/julien/linux/
Serial port settings for the terminal:
port : Virtual com port (e.g /dev/ttyUSB1 or /dev/ttyUSB0
or COM5 under windows or ... whatever port the
virtual com-port maps to)
Under linux or Mac you can use the command dmesg
after you have plugged in the USB cable to see to
which com-port/device the new virtual com port maps to.
Under windows you look at Control Panel->Hardware->Devices
and click on FT232R USB UART->Hardware to see the COM
port.
baudrate : 9600
parity : none
flowcontrol: none
stopbits : 1
databits : 8
Controling the power supply with scriptable commands
====================================================
You can control the digital power supply by commands. A number
of commands are provided for this purpose. They are at the moment
available for Linux, Mac and Windows:
ddcp-script-ttyinit - initialize the COM port (run this once at
at the beginning)
ddcp-script-getval - get current values (same as you see on the LCD)
ddcp-script-setval - send a command to the power supply
ddcp-script-example.sh - an example unix shell script showing how to use
the above commands
To compile the ddcp-script commands under linux and on the mac
use the command:
make ddcp-script
The windows versions of those commands are available in the
sub-directory "ddcp-script-windows". The windows versions
are compiled in that sub-directory with the command:
make
Pre-compiled binaries are available for winXP.
-------------------------------------------------------------------
Software License:
Copyright: GPL V2 (see http://www.gnu.org/licenses/old-licenses/gpl-2.0.html )
Author: Guido Socher (guidosocher@gmail.com)
Homepage: http://www.tuxgraphics.org/electronics/
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Change history:
digitaldcpower-0.6.0 -- 2010-05-22 first version of the new power V3.
This version is made for a new type of hardware
and will not run on any previous hardware version.
digitaldcpower-0.6.1 -- 2010-06-06 Number conversion to display string
improved.
Basic uart interface prompt, no remote control yet
digitaldcpower-0.6.2 -- 2010-06-26 Full UART command interface
digitaldcpower-0.6.3 -- 2010-07-03 Accelerate UART command polling to
not loose characters when copied/pasted at high speed.
Line editing with backspace if terminal supports it.
Set BOD (brown out detector enable) fuse.
Script interface (ddcp-script)
digitaldcpower-0.6.4 -- 2010-07-11 added ddcp-script interface
commands for windows.
digitaldcpower-0.6.5 -- 2012-04-14 There was a fault in the range setting
for the PWM (ICR1L in dac.c). Thanks to Weitao Li (james)
for reporting this. This fault reduced the precision
a bit.
-- 2012-04-14 some minor improvemnents in main.c and analog.c to
regulate the voltage drop over the current measuremtns shunts
faster.
digitaldcpower-0.6.6 -- 2012-07-17 Adapt the code to compile clean with the latest
avr-libc (http://www.nongnu.org/avr-libc/changes-1.8.html)
prog_char is now depricated.
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