Objective Development Forums

Getting started with AVR-USB

2007-08-02T14:20:12+02:00

No problem to mail you libhid.a, but I need your email address. Can you please get in contact with us through the support web form?

Statistics: Posted by christian — Thu Aug 02, 2007 2:20 pm

Same problem

2007-08-02T01:44:05+02:00

I have exactly the same problem as Rich. D you mind email me your libhid.a please.?

thank you

Statistics: Posted by Guest — Thu Aug 02, 2007 1:44 am

Getting started with AVR-USB

2007-03-26T20:54:36+02:00

yeah i see what you mean. i'll have it working quite nicely with hyper terminal one minute and then the terminal crashes. noteably its always the 4th time i go to send a text file it always seems to crash on the open file dialog box. however putting the baud rate down to 110 appears to give consistent behaviour...not ideal really.

Statistics: Posted by Guest — Mon Mar 26, 2007 8:54 pm

Getting started with AVR-USB

2007-03-23T19:36:47+02:00

AVR-CDC is a bit problematic because it goes somewhat beyond the USB specification. If you look at Osamu's documentation, you'll see that the device does not work with all PCs and operating systems.

I had good experiences with my hardware (an Apple iBook, a PC notebook running Windows XP and an Apple iBook running Linux), although I never implemented Osamu's original project. I used CDC in AVR-Doper, our AVR programmer. Others get consistent failures, sometimes after transferring several kB without error.

Statistics: Posted by christian — Fri Mar 23, 2007 7:36 pm

Getting started with AVR-USB

2007-03-23T18:51:03+02:00

adding the two zener's did the job, havnt had any enumeration problems since and the automator appears to work on all computers.

i've just been having a go with the AVR-CDC - a USB to Serial Converter, the device attaches to pc's fine but the instructions on the terminal seem a bit strange. i've got some LED's hooked up to port C of the circuit and am jus try to get them lit using a command such as:

FF PORTC = (as specified by the readme + website)

my understanding is that this should set portC high and my LED's should light.

Im using Docklight V1.6 as my terminal. Initially i could only get the "!" character out of it which upon inspecting the code was a good sign as its the error character. now as the error code was being returned i wasnt surprised that the LED's didnt appear to be working.

i tried flipping the command strings in the terminal (= CTROP FF). i now get a return off of every command, however the data at an address always takes the value 08 or 00??? even after setting it to something else which appears to work correctly an give the correct error code.

does this project work properly? i cant see in the code where the later following PORT is checked and used? can you suggest a better terminal to use on windows? and any hints for making this project work? i cant see any good reason why it shouldnt be straight forward to implement.

regards

Rich

Statistics: Posted by Guest — Fri Mar 23, 2007 6:51 pm

Getting started with AVR-USB

2007-03-21T12:01:26+02:00

Issue 2 is independent of the PC. The effect is that you store a sequence, everything works well and you leave the site. After two weeks you get a call that it stopped working. When you look at the contents of the EEPROM, parts of it have been overwritten with simple patterns.

This problem occurs with the supplied code. We have not yet identified the real cause, whether it's a hardware problem (brownout?) or whether it can be worked around in firmware (e.g. by parameter validation).

Statistics: Posted by christian — Wed Mar 21, 2007 12:01 pm

Getting started with AVR-USB

2007-03-20T23:25:09+02:00

ah right, will try attaching the zener diodes first.

with respect to issue 2:

would this stop the device from operating on all pc's? it currently works on one that we know of but not on others.

as we are using the supplied automator code could false USB packets occur?

regards

Rich

Statistics: Posted by Guest — Tue Mar 20, 2007 11:25 pm

Getting started with AVR-USB

2007-03-20T19:39:23+02:00

There are two issues with Automator:

The first version of the circuit did not have zener diodes on USB D+ and D-. On some PCs and hubs, this exceeds the common mode range of the input driver. Simply add 3.6 V zener diodes at D+ and D-, directly at the connector pins.
The firmware is not transient-safe. If a transient triggers a false USB packet, little checking is done and the EEPROM may be overwritten. More status checking is required in usbFunctionWrite().

It is also true that PCs store all devices which have been connected so far. Devices are identified by VID/PID pair. They can be removed in the Device Manager.

Statistics: Posted by christian — Tue Mar 20, 2007 7:39 pm

Getting started with AVR-USB

2007-03-20T18:13:32+02:00

Hi,

gave up on using Visual Studio's a while ago. We're encountering major problems with the automator. initially we had the device working to the extent we could write code to the eeprom and retrieve it. which is essentially what we are after for our application. no it randomly stopped working after a couple of weeks. we had swapped out all of the components in the circuit and had pretty much given up hope on it working again when it started working again a couple of nights ago. When in a lab earlier on it then stopped working again. We tested it on a couple of machines. However when returning home and plugging the device into another laptop it appeared to be working again. Is there any reason why the automator should enumerate on certain machines but not any others? and if so a way around it? we are basically getting the unrecognised usb device error when plugging the device in (what i mean by not working)

does the pc store a memory of previous devices maybe and could this be causing conflicts? if so can these be deleted?

regards

Rich

Statistics: Posted by Guest — Tue Mar 20, 2007 6:13 pm

Getting started with AVR-USB

2007-03-07T13:50:46+02:00

I have never tried MS Visual Studio myself, so I can't comment...

Statistics: Posted by christian — Wed Mar 07, 2007 1:50 pm