Objective Development Forums 2013-04-13T10:41:57+02:00 https://forums.obdev.at/app.php/feed/topic/8377 2013-04-13T10:41:57+02:00 2013-04-13T10:41:57+02:00 https://forums.obdev.at/viewtopic.php?t=8377&p=25124#p25124 <![CDATA[Re: V-usb and serial communication]]> Are you using a MAX232 with ceramic capacitors as RS232 tranceiver?
Maybe you need a small (blocking) capacitor on your board between Vcc and GND.
The carge pumps of MAX232 seems to generate lots of noise, which ripples you have to smooth.

Best regards,

Statistics: Posted by Guest — Sat Apr 13, 2013 10:41 am

]]> 2013-04-02T00:34:10+02:00 2013-04-02T00:34:10+02:00 https://forums.obdev.at/viewtopic.php?t=8377&p=25050#p25050 <![CDATA[V-usb and serial communication]]>
My english is not the best so i apolagyse :)

I'm trying to do something new with the HID keys. I grabbed the hid keys project and changed to receive data through serial port instead of pressing buttons but a problem appears.

I did a little program that receive data and do echo. The problem is the echo is not the same that i sent to avr microcontroler. I already deleted and changed the part of the code of v-usb that makes the degub for i can use the usart.

I'm using a crystal of 16Mhz and configured the usart to work with a 19200 baud rate.

The problem seems to be about speed because when i change de baud rate to a lower value the data that appears in echo is more like the data that i have sent.

I also test the receive/transmit data program in the same circuit but without the hid keys program and it works fine. I change the fuse bit's of atmega8 for he can work at this frequency.

If someone can help me i'll be grateful :)

Statistics: Posted by Trindade — Tue Apr 02, 2013 12:34 am

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