Objective Development Forums

Hello. I have some questions related to V-USB.
1. Does V-USB allowing "real time" communication of an uC with the computer via USB?
2.If so, what are the steps for a small application of this type? For example turning on and off a led, using Atmega8?
first..should i load the firmware on the uC..then write a code or something in a compiler? and which would that be? if you can explain it to me like for greenhorns.. thanks a lot guys .

Hi

raubercata wrote:1. Does V-USB allowing "real time" communication of an uC with the computer via USB?

That depends on what you mean by 'real time'. From a technical point of view the answer would be no, however from a user's perspective it could possibly be considered as such (think: keyboard/mouse). Read the spec for USB 1.1 for exact details.

raubercata wrote:2.If so, what are the steps for a small application of this type? For example turning on and off a led, using Atmega8?

If this is your very first MCU project then I suggest you begin with something much simpler, like flashing a LED (without USB). Once you are familiar with your chosen toolchain then try some of the provided examples that come with the driver (V-USB). One of them does exactly what you are asking for

As for compiler, if you are using Windows then you might want to look at WinAVR. It's free and works well with the equally free AVR Studio IDE.

Good luck.

This is not my first MCU project. I know pretty much about LCD, different types of motor interfacing... interrupts, ADC etc.
I just wanna know for example if i write a command line in avrdude or something, the uC will execute it immediately. Or V-USB is just some kind of programmer like USBASP? Is it possible to turn on a LED just by writing a command line on the PC and then via USB this command reaches the uC and it's been executed?

I wrote the hex file on the atmega8, and as from the description, i tried to type the command "make" in the directory commandline. it displays the following error:
gcc 'libusb-config --cflags' -O -Wall -I../common -c usb-led-fader.c
/bin/sh: libusb-config: command not found
/bin/sh: gcc: command not found
make: *** [usb-led-fader.o] error 127

i have though libusb installed...why this error?

i managed to compile the makefile using mingw, and i got the usb-led-fader.exe. the problem now is that when i plug the device in the usb port, windows shows me a "usb device not recognised" message, and in commandline when i type usb-led-fader status i get this error: "could not find usb device "usb-led-fader" with vid=... pid=... ". any suggestion? it might be because i didnt set the fuse bits? i thought that is only for new uC, which had never been programmed.

Well I have exact the same problem with switching on one of those exampale ;0 The same info that windows don't recognise the device. We set the fusbit for 16MHz Oscillator and generally that's all :/ And of course change the Config.h cause of difrent bit of portD usage.
I'm not really familiar with uC :d but know some basic basics

Delvier wrote:Well I have exact the same problem with switching on one of those exampale ;0 The same info that windows don't recognise the device. We set the fusbit for 16MHz Oscillator and generally that's all :/ And of course change the Config.h cause of difrent bit of portD usage.
I'm not really familiar with uC :d but know some basic basics

And how did you set the fusebits? because i used extreme burner avr...set the fuse bits as its says in the pdf and i've ruined my uC

The only thing what we have changed was the external oscillator and generally nothing more . Now I'm trying to run the Hid-Mouse exampale. I use the super make file to generate hex. And trying to load it into my cool Usb to I2C project. We see how it works. I wonder if I change make file right

OK . I run the hid mouse When i Checked by AvrOsp my fuse bit high and fuse bit low for external osci I found out that on make file I have a diffrent Copied from below exampale

now i use ! :
High: 0xD9
Low : 0xFF

And it works cool !

Delvier wrote:OK . I run the hid mouse When i Checked by AvrOsp my fuse bit high and fuse bit low for external osci I found out that on make file I have a diffrent Copied from below exampale

now i use ! :
High: 0xD9
Low : 0xFF

And it works cool !

well i dont quite understand. you set these fuse bits from above for a 16 mhz oscillator , thats right? well i need fuse bits for a 12 mhz oscillator. and if they are
High: 0xC9
Low: 0x9F
as the description of the project says ...then they're wrong, coz the uC is now locked.

well... i managed to 'unlock' the uC. i simply disconnected the ground from those two 22pF capacitors, and probably the XTAL1 took some kind of clock from the crystal , otherwise i cant explain it. then the question is remaining... why 0xC9 and 0x9F does not work for a 12Mhz crystal????

Problem solved. With those two capacitors removed i flashed once again the uC and wrote the fuse bits and everything works fine. Project done!

also having Driver Power State Failure

Mail a friend send me when I got this issue again

Related to amd_sata.sys AHCI 1.2 Device Driver from Advanced Micro Devices.

I would run a system file check (just to verify the OS) and go to the computer mfr and see if there is a newer driver. I would also see if there is a newer BIOS

To run a system file check (SFC)
Go to start>type CMD>right click and run as administrator> Type SFC /scannow

let us know what it says at the end.
You may have to run this up to 3 times.

http://www.deskdecode.com/driver-power-state-failure/