Re: Data transfer methods

From: Jim Brain (
Date: 2005-05-12 09:06:33

Marko Mäkelä wrote:

>On Wed, May 11, 2005 at 06:55:10PM -0500, Jim Brain wrote:
>>From my work with FAT, it appears only the space char is illegal in a 
>>FAT filename.
>Didn't you forget about other metacharacters [<>*?/] and
>the colon?  Also, deleted file names are marked with 0xe5 or something
>like that in the first character of the file name.
If an 0xe5 is needed, you can use 0x05, which is interpreted as an 
escaped e5. 

0xe5 cannot be used (use 0x05 instead)
space can not be used, as it marks the end of the name and the extension
00 cannot be used, as it indicates a empty dir entry.

As for the metacharacters, I'm not sure you need to stay away from them 
anymore.  I would think puting quotes around them would escape them from  Windows does not let you create entries with them, 
but I think that is just to support older apps that don't understand 
quoting.  One of these days, I'll create a FAT entry with the invalid 
chars and see what happens in Windows.

>Have you set up a project page that could be linked to?
In time :-)  I just got the code working last week.

>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.

Atmel also has USB devices as well. 

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.  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.  The USB 
HID CBM keyboard might be doable, though, as plenty of code exists for 
HID support for both uC and Atmel.  You might be able to masquerade the 
IEEE/IEC interface as a USB drive if you only wanted to support talking 
to drives, but supporting a C64/128 talking to the PC via USB I can't 
think of a USB fmaily that would fit into.


Jim Brain, Brain Innovations                      
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!

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