Re: c2n232 question (PET 8032/8296)

From: Marko Mäkelä <>
Date: Sun, 8 Aug 2010 19:56:47 +0300
Message-ID: <20100808165647.GB3218@x60s>
On Sun, Aug 08, 2010 at 02:44:38PM +0200, Nils Eilers wrote:
>Did somebody try to connect a FT232RL USB-serial-adapter-chip directly 
>to the ATtiny2313?

In 2003, I had trouble with the FTDI drivers. Bit-banging did not work 
(not that the C2N232 requires it), and neither did XON/XOFF or CTS/RTS 
handshaking. I tried it both on Windows XP and Linux, and FTDI technical 
support was not helpful.

I guess that most RS-232 applications are receiving data to the USB 
host, and there this buggy handshaking does not matter, because the USB 
host typically has enough processing power to handle all the incoming 
data. In the C2N232, the data flow is the other way around. The C2N232 
does have a 124-byte receive buffer, and it does handshaking when the 
buffer is 3/4 or 1/4 full, but that didn't work.

I believe that PL2303 is one of the least worst choices on Linux. It is 
one of the first supported USB RS-232 adapters, and the driver was 
implemented by Greg Kroah-Hartman himself, if I understood correctly.  
Nowadays it could make sense to implement a C2NUSB that talks USB 
CDC-ACM directly, if someone likes a challenge or has too much time in 
their hands. :-)

My PL2303 based adapter once worked in Windows XP. Next time I tried, it 
didn't work. I have booted Windows XP on that computer probably less 
than 20 times in about 3 years, and I have installed some updates in 

On Linux, I have recently had some difficulties ("unexpected response 
from C2N232").  That could be due to failing USB connectors on my 
laptop. My USB-based CompactFlash card reader often resets the USB 
connection while transferring less than 100 megabytes of photos at USB 
2.0 speed (480 Mb/s), no matter which connector I use on my laptop. I 
have resoldered the connector on the CF card reader a couple of times, 
but it did not help this time.

I guess that today's computers are not meant to last longer than 3 years. :-(

Best regards,


       Message was sent through the cbm-hackers mailing list
Received on 2010-08-08 17:00:03

Archive generated by hypermail 2.2.0.