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16  Using Arduino / Project Guidance / Re: MAX voltage level for 5v arduino question on: March 10, 2013, 09:02:36 am
I have used 4xAA rechargeble batterys before, measured at about 5,5v, and did not have any problems with that so far
i even use them to connect through the arduino connector, but passing through the on board regulator means you lose about 1 volt (tested on my mega1280)

hope this helps
17  Using Arduino / Project Guidance / Re: Arduino 2560: ISP for ATMEGA2560 on: March 10, 2013, 08:52:46 am
I think the basic principles apply to an atmega 1280 or atmega 2560
if it is a arduino board, it has a icsp connector you can use
if not - look in the datasheet to find out what pins to connecto to 5v, gnd, miso, mosi, clk, and off course reset
and off course connect a crystal

maybe post pictures, more information if the target is a bare ic or a board, will get you some more help ?
18  Using Arduino / Project Guidance / Re: ArduinoISP on serial rs232 on: March 09, 2013, 09:29:42 pm
I was wondering if you have a spare pcb for that programmer you built?
Only thing that is missing for what I have in mind is a zif socket to program bare chips smiley
I also wonder - if there is no sd card - can you upload a sketch like you do with the arduino/avrdude ? Like if you want to test and find out you need to change things, do you have to compile and put the new hex file on the sd card first?

If you plan on adding an lcd - consider using a touch screen - that would make an awesome interface, but would probably force you to use a mega (for extra pins and memory)


update: still no joy - but I have to admit I got a bit distracted and didn't spend much time on it these last days
I am uncertain about a reset line on the programmer though - from what I learnt so far I don't need to reset the programmer when the serial communication starts
using the uno as a programmer I disable the reset signal using the cap, right?
and the arduinoISP sketch resets the target when it needs to, right?
Just double checking the obvious things - correct me if i'm wrong

so far I think the serial connection is not working right - but I'm still not sure. maybe the arduino/avrdude doesnt like the usb to serial pl2303? I'm going to try and verify that when I find some more time - use the uno but connect the max232 to the tx/rx pins and see if that works


19  Using Arduino / Project Guidance / Re: ArduinoISP on serial rs232 on: March 08, 2013, 06:45:05 am
Yes, a standalone programmer would be very nice for the 'hidden' modules, and I probably will end up building me one of those in the end
I did come across your site in an early search how to make a standalone 328p, and how to set the fuses correctly. Is it my idea or has your project actually evolved a lot in the last half year or so? I am definately going to have to reread all your information. Thanks for sharing and documenting your ideas! (btw - the arduinoISP adafruit version uses the exact 8Mhz pin 9 idea - one of the reasons I use that version)

but for now I want to try and get this experiment running, learning along the way how everything works, get a better understanding of the whole process. This evening I hope to continue and find out what is going wrong exactly

And as I'm also still learning to program, I do feel I need a direct link between the computer and the module, as I seem to need a lot of debugging and testing to get things working

Right now struggling with a test setup of a wireless module and pointers in C - which is actually the direct motivation of trying to build this programmer - I was fed up with the Uno's flaky behaviour as an isp, and swapping the 328p in and out of the module to test things

(the uno totally dislikes being unplugged from my usb and plugged back in - it flashes the pin13 led fast and is totally unresponsive - I have to reprogram the sketch to get it working again - I have not been able to find more info on this weird behaviour - but I figure it has to do with the usb connection in some way)
20  Using Arduino / Project Guidance / Re: ArduinoISP on serial rs232 on: March 07, 2013, 09:43:38 pm
almost ...

the isp is not permanent (to save costs - I plan on having several 'targets')

the target is 'hidden', but I would have a connector that can be reached - and would allow to reprogram and debug
the isp would be hooked up to this connector to allow reprogramming fuses/sketch - maybe even serial communication to allow debugging
so basicaly - a icsp header with added tx/rx - would cover everything I think

so far not much joy on my breadboard experiment - but i'm pretty sure it can be done
I must be overlooking something obvious and simple - right now I'm having trouble using my Uno as isp too

Ah - it is very late and sleep deprivation doesnt help with this sort of thing smiley-sad
Thanks for your insights, they really help a lot!

quick update:
using usb and the uno as isp - i can program a target on the breadboard
but using rs232 and a 328p i keep getting an error 'avrdude: stk500_recv(): programmer is not responding'

tomorrow I'm going to double check that serial communication is working, and I'm going to try serial communication with the uno as isp
Any other trouble shooting tips are welcome

btw - using the uno as isp is problematic, to say the least - i'm not even going into that as I don't think it is related, or relevant to this experiment


21  Using Arduino / Project Guidance / Re: ArduinoISP on serial rs232 on: March 07, 2013, 08:30:57 pm
mmm - yeah - I guess it gets confusing
first want to thank you for your info - I came across it in my search for breadboarding up a 328p, and reprogram the fuses, and it helped me a lot!

So let me try and explain what I want to do exactly:

the mac is running arduino ide - it has a prolific 2303 usb to rs232 converter
-
(long) rs232 cable
-
a max232 chip converts the signal to ttl and is part of the (battery fed) programmer - which is basically a 328p running the arduinoISP sketch
-
which programs the target, a 328p low voltage module which is in a difficult to reach place


my motivations?
why rs232? is an easy way to bridge quite a long distance - and I have the parts on hand
why not program the target through a ftdi/bootloader? usb cables are limited in length - ftdi does ttl serial - also limited in cable length I'd think
why the more complex programmer approach? I need one anyway to reprogram the fuses - so i figured to make it multi functional - and I'm fed up with having to pull my uno from other projects any time I need to program a 328p. And I have a couple of 328p to spare smiley

alternatives I have considered?
rs232 cable and reset the 328p using the rts signal - using a standard optiboot bootloader - which is something I will try too. Main disadvantage: you can't program the fuses or bootloader
ethernet or internet programmable modules ... some people are working on a bootloader that allows programming the 328p over the internet - but it is far from ready yet

my goal? design a module that can be permanently integrated in my house. figure out what connections the target has to have so I can reprogram it later without having to redesign it. So far I figure, if I have a icsp connector - and maybe add the tx/rx combo, I can reprogram the fuses and the sketch without having to remove the module
22  Using Arduino / Project Guidance / Re: ArduinoISP on serial rs232 on: March 07, 2013, 06:22:34 pm
i don't think so ...
I am using a 328p with the arduinoISP sketch as a programmer - to program a module based on a 328p

When I use a arduino Uno as the programmer, I have to use a capacitor to prevent the uno to reset when the ide starts sending code
it is the programmer that resets the target, using pin 10 wired to the reset of the target

But please correct me if I'm wrong on this

I understand that programming an arduino directly with rs232 would need this functionality.
I do plan to try this approach too, but for now I need a programmer anyway as I reprogram the fuses too on the target. I have done this using a arduino Uno as a programmer so far, but now I want to make a dedicated programmer
23  Using Arduino / Project Guidance / Re: ArduinoISP on serial rs232 on: March 07, 2013, 05:16:33 pm
I think my setup is not too far off from this ...

On the mac side I use a usb to serial converter based on the prolific 2303 chipset - this is true rs232

On the arduino programmer side I use a max232 chip to convert to ttl level

So far I have not figured out the reset trick with rts - (My max232 chip doesnt have the connection for that) - but I don't think I need to in my case?

As the arduino/328p modules are low level battery powered, and I don't want to risk damaging components (nRF24l01 wireless module - to name one) that are not meant for 5v, I want to use a programmer to (re)program. I plan to make the programmer battery powered and switchable between 3,3v and 5v. This way I can have a long cable run. (tested 20m between this pl2303 and a siemens logo and that worked flawless)

There is more coming, but for now, I want to get the basics working.
I am going to go over everything again, double check connections, probably some minor detail.

But from what I read here, I'm pretty certain my idea is feasable
thank you for the feedback

If anyone is interested in my progress, I'm happy to share
24  Using Arduino / Project Guidance / ArduinoISP on serial rs232 on: March 06, 2013, 09:24:50 pm
I want to build my own programmer using a 328P running the arduinoISP sketch, and rs232 to hook it up to the computer
I want to use the arduino IDE to program the target (using the menu entry "upload with programmer")

I gave this idea a try on a breadboard and it doesnt seem to work - "avrdude: usbdev_open(): did not find any USB device "usb"

Did anyone try this idea, and get good results? Or does the arduinoISP sketch only work via usb?

Some more details for those that are still reading:
Mac Running IDE 103, arduinoISP sketch is the adafruit version (works on an Uno board)
selected the correct board, selected the correct serial port, selected arduinoISP
I verified the serial communication is working (9600 baud with another sketch)
Hardware is shown on http://avrprogrammers.com/bld-avr-arduino-isp-232.php

Why do I want to do this?
rs232 allows for longer cables than usb, and you can easely solder the connectors yourself. I need to bridge some distance between the computer and the arduino/328P modules i want to (re)program
25  Development / Other Software Development / Re: _FILL(char c, int len) for Streaming library on: March 02, 2013, 06:27:04 pm
Hi, I'm looking into the streaming lib and found your link
would you mind explaining what some of this stuff does?
I'm trying to make some examples for myself for future reference
Thank you
26  Using Arduino / Project Guidance / Re: Uno Reference Voltage of 1.1v on: January 29, 2013, 10:05:32 am
Oh - it is not like I desperately need any of this - I'm just exploring the arduino platform and trying to figure out stuff to get a rough idea of the possibilities
and if anyone is that desperate for an extra pin - the price on mega2560 clones has dropped dramatically to the point where you can find them for nearly the same price as a uno clone. Just have a look on ebay!

The usb 1.1 hub is actually powered - and has given me years of trouble free use. I don't plan to get another one. I just have to keep in mind that vcc is below 5v when using my arduino. Which only seems an issue when I want to do analog measurements.

Those adc chips look tasty - I hope to get my hands on them one day and play around with them.

27  Using Arduino / Project Guidance / Re: Uno Reference Voltage of 1.1v on: January 28, 2013, 04:37:30 pm
way ahead of you there ...
when I use the computers usb ports all is fine!
just this usb 1.1 hub
I have not looked into it that much further - it doesnt bother me since I figured out a way to measure the vcc
which actually was a good idea since I need this when I want to run my arduino off batteries.

I just got fascinated by the whole bandgap idea because it doesnt involve sacrificing an analog pin.

thanks for your reply, and thanks for sharing your bandgap experiments
28  Using Arduino / Project Guidance / Re: Uno Reference Voltage of 1.1v on: January 28, 2013, 04:04:11 pm
just want to add my two cents - I am researching how to measure battery voltage through the bandgap method

if you connect the batterys to the vin barrel - you are not going to get the same voltage on vcc - far from it. The battery voltage goes through the voltage regulator. If at all possible - hook up your battery pack to vcc. (assuming it is not over 5.5 volts and not reversed!)
So the results you measure may actually be correct

hooking up an arduino to usb does bypass the voltage regulator
however - this does not garantuee a clean 5v vcc
when I hook my arduino up to a usb 1.1 hub - I get around 4,3 volts on vcc
it took me quite some time figuring out why analog temperature sensors would give bad results. I finally figured out a simple trick, measure the 3,3v line on an analog pin and use that to calculate the voltage on Aref. This did cost me an analog pin. I am looking into the bandgap method for future projects.

Thanks to coding badly and lefty for some great posts on the subject.

May I point to another great source on this subject?

http://jeelabs.org/2012/05/04/measuring-vcc-via-the-bandgap/
http://jeelabs.org/2012/05/12/improved-vcc-measurement/
29  Using Arduino / Networking, Protocols, and Devices / Re: ENC28J60 + Arduino = FAIL!!! on: December 27, 2012, 08:49:52 am
well - i did get the enc28j60 working with the ethershield v1.1 library - just that as a novice i did not find many examples for it

I managed to get the ethercard library working too, with a small fix for my particular setup. (it seems it expects the cs pin to be wired to pin 8 - on my setup I have it on pin 10) This library seems to produce bigger code than the ethershield library, but it includes more examples, and seems to be more widely used.

Arduino Uno R3, arduino 1.0.2, cheap enc28j60 board wired to pins 10 to 13

Thanks for your help, PaulS

I think I'm going to get a w5100 based ethernet shield, and learn more about the supported ethernet library first, I might come back to the enc later.
30  Using Arduino / Networking, Protocols, and Devices / Re: ENC28J60 + Arduino = FAIL!!! on: December 26, 2012, 03:08:07 pm
yes it does
i just moved the serial print commands to the right so i'd have a clear overview of where they were.
don't worry too much about it - i was just trying out the code I found in this thread.
Right now I'm looking into the ethercard library

I must say - it is so difficult for a beginner to find a working, up to date, and well documented library.
Having many librarys is good, but it really confuses the novice like me

Maybe i'd better get a w5100 based ethernet card?
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