General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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Guest
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by Guest » Fri Jun 13, 2008 1:29 am
Would it be possible to implement a USB serial port device with AVR USB? That is, when plugged in, I want the AVR USB device to appear to the host as a COM port.
High speed communication is not important - I just want users to be able to open up Hyperterm and interact with the device.
I know I could do it by using a USB UART chip like a FT232, but I'm just wondering if it could all be done in software.
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Guest
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by Guest » Fri Jun 13, 2008 6:12 pm
Thanks! I missed that project.
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christian
- Objective Development
- Posts: 1443
- Joined: Thu Nov 09, 2006 11:46 am
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by christian » Sun Jun 15, 2008 8:15 pm
I want to add a note: Projects based on AVR-CDC don't work on all operating systems and they may fail on some hosts. If you want a device which you can sell to others, please find a different solution. If you want something which works for you, then just build it.
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bassai
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by bassai » Sun Jun 29, 2008 12:04 am
I tried to implement a AVR-USB device with USART interface to another AVR.
But I get USB timeouts and my USART doesn'T work.
dmesg: usbfs: USBDEVFS_CONTROL failed cmd usbtest rqt 64 rq 1 len 4 ret -110
Any ideas? I have DEBUG_LEVEL=0...
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christian
- Objective Development
- Posts: 1443
- Joined: Thu Nov 09, 2006 11:46 am
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by christian » Mon Jul 07, 2008 5:24 pm
If you use interrupts for the UART, you must declare them so that the USB interrupt can interrupt the UART interrupt.