Re: Data transfer methods

From: Marko Mäkelä (
Date: 2005-05-12 09:50:44

On Thu, May 12, 2005 at 02:06:33AM -0500, Jim Brain wrote:
> If an 0xe5 is needed, you can use 0x05, which is interpreted as an 
> escaped e5. 
> 0xe5 cannot be used (use 0x05 instead)

So, 0x05 cannot be used.

> As for the metacharacters, I'm not sure you need to stay away from them 
> anymore.

I think using them in a FAT filesystem is asking for trouble.  You know,
if someone still uses Commodore computers, he might also use some weird
MS-DOS 2.11 based computer. :-)

> >Yesterday I noticed that Microchip's PIC family of microcontrollers has 
> >been
> >extended by some USB capable ones, such as the 18F2455.  The chips in that
> >family should be sufficient for a combined USB to IEEE-488 and serial bus
> >interface (and maybe cassette as well).  Any takers?  The same chip could
> >also be used for adapting Commodore keyboards to USB HID.  The only open
> >question is: how do you flash the firmware over the USB?  I didn't find any
> >Linux-related documentation for that.
> > 
> >
> I would think it would be tough to do, as you need a simple enough USB 
> protocol so the bootstrap loader/programmer code can run it, and USB is 
> just not that simple.

If I understood correctly, the controller might have some boot monitor code
loaded at the factory.  After all, it has 24 kilobytes of program flash.

> No taker here.  at least not yet.  USB is not nearly as easy to 
> implement, and unless you can shoehorn your project into a 
> well-supported USB family like HID, you're into writing device drivers 
> for each OS you intend to support.

True.  It's a pity that there is no predefined class for data transfer or
even digital cameras.

> My plan is still RS232, and maybe integrate the FDTI chipset for USB
> support, as drivers exist for that USB device that makes it look like
> a serial port to the system.

My advice is to stay away from FTDI.  Their Windows drivers are buggy,
and Linux support is lacking as well (it doesn't support XON/XOFF
handshaking, although the hardware does).

The Keyspan USB to serial adapters, which have been proven to work with
the C2N232 on Mac OS X, are based on the EzUSB microcontroller.  That
controller only has RAM, and you will have to download the firmware over USB
every time before using it.

> You might be able to masquerade the IEEE/IEC interface as a USB drive if
> you only wanted to support talking to drives

Oh yes, that would be elegant, although you'd need to write file system
drivers (such as Linux cbmfs) in order to do anything else than copying
disk images.

> but supporting a C64/128 talking to the PC via USB I can't 
> think of a USB fmaily that would fit into.

USB HID with custom software on the PC, perhaps?  Nah, it would be too slow.
Maybe something with libusb?


       Message was sent through the cbm-hackers mailing list

Archive generated by hypermail pre-2.1.8.