Re: c2n232 question (PET 8032/8296)

From: André Fachat <>
Date: Sat, 07 Aug 2010 11:52:18 +0200
Message-ID: <>
Hi Anders,

thanks for the info.

-------- Original-Nachricht --------
> understood, the USB to RS232 adapter consists of at least two parts:
> * The RS232 emulating chip which can be a PL-2303, HL-340, Keyspan or some
> other design.
> * A chip to convert voltage levels to TTL. If I understood correctly, the
> USB port natively has -7V and +12V.

The USB port has GND, +5V, Data- and Data+ (it's a differential, timeshared-bidirectional signal), and that's it. (USB3.0 is different, it has additional wires)

So you have to create the RS232 voltages from the 5V.

> Now, some adapters have a solution to both these factors. Some adapters
> only emulate the RS232 signalling without bothering about signal levels.
> Some implement the TTL levels with a special chip that limits transfer
> speeds, while others don't. Sometimes an adapter that is known to work
> can be changed without notice by the manufacturer, and you will buy a
> different adapter than you thought you did.

So maybe if mine does not work, but has a PL2303, it could be the voltage converter, or the transfer speed?
The voltage I can probably measure, is there a way to adapt the transfer speed of the c2n232?

> I ended up using a built-in serial port, for which the C2N232 works fine.
> However I've had quite some issues running the cbmlink client software,
> both on 3032, 4032, 8032 and VIC-20. So far the only machine on which the
> cbmlink works reliably is the CBM-II line: 610 and 710, probabaly because
> the cassette port isn't normally used by the Kernel in those.

What problems do you have? I used cbmlink with the PC, but only occasionally for now, without problem. I'm using a 8296, using the "-m 8032-1" switch.

> Actually I have a serial port EPROM programmer which I connected to my two

My EPROM burner and my GALBLAST is for the LPT port, that the laptop still has, only the software is for windows only :-( 
Also the XILINX jtag cable works on the laptop's LPT port, but that runs on Linux too :-)


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Received on 2010-08-07 10:00:37

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