GP2X Zmodem For Gp2x

[bjimba]

Just in case this is of some use to anyone else -- I've ported lrzsz to the GP2X, using ooPo's excellent toolchain. This is only useful to those of us connecting to the GP2X via serial or USB gadget interfaces, so I'm just posting it here in the Developers' section. It's working for me for both send and receive, and beats moving the SD card back and forth just because I forgot a config file.

http://bjimba.blogspot.com/2006/02/zmodem-for-gp2x.html

 

[Vimacs]

pf, been there, done that, about one or two months ago
well, great wok anyway.

 

[gfoot]

Are you doing this over the USB gadget serial link, or a real serial line? If the USB one:

• What kind of transfer rates do you get?
• Are you using ACM (null modem) mode, or bulk mode?
• What OS is the host running?

So far using custom code I've only managed about 50 Kbytes per second over a bulk gadget serial link, I'd be interested to know if you're seeing better rates than that!

 

[jan_europa]

USB gadget serial link

I think more or less: 5k/s

windows XP hots

¿where is your custom code boy, I need it?

 

[DijiTao]

Zmodem Wow does that take me back. Wasn't Zmodem the protocal were you could upload and download to the server simulataniously? I seem to remember using it on BBS with file download ratios.

 

[reaper79]

Zmodem Wow does that take me back. Wasn't Zmodem the protocal were you could upload and download to the server simulataniously? I seem to remember using it on BBS with file download ratios.

​

I though Zmodem had error detection/correction on transfers? Been a while since them BBS days. Anyone remember Kermit protocal or Night Owl?

Cheers!

 

[bjimba]

Are you doing this over the USB gadget serial link, or a real serial line? If the USB one:

• What kind of transfer rates do you get?
  
• Are you using ACM (null modem) mode, or bulk mode?
  
• What OS is the host running?
  

So far using custom code I've only managed about 50 Kbytes per second over a bulk gadget serial link, I'd be interested to know if you're seeing better rates than that!

​

I'm using the USB gadget link, thanks to you, gfoot!

Transfer rates: 35Kbps when going from GP2X to host. When going host to GP2X, I get transient rates about the same, but then it stops to think it over every 100kb or so, so I end up with an effective rate of 4 or 5Kbps. It's not really a big concern to me, because for large file transfers, I'm happy to swap the SD card to my host card reader. It was just the times when developing where I found I had forgotten to place one file or another on the SD that I wished I could just upload it to the GP2X without shutting down the USB gadget driver.

I'm using ACM mode on a Debian Linux host.

 

[luteijn]

you can't just umount the sd-card, without shutting down the gp2x? afaik that works fine for me... so I never bothered to build sz etc.

P.

 

[DijiTao]

I just remember using Ice Zmodem -- and it kicked ass... I did some googling trying to remember thoese bbs days – came across Bi-Modem which sounds like what I remember... Does anybody remember this stuff it's bugging me that I can't...

 

[bjimba]

you can't just umount the sd-card, without shutting down the gp2x? afaik that works fine for me... so I never bothered to build sz etc.

​

Well, yeah, I can, but the Zmodem transfer saves me a few steps. Different strokes for different folks.

 

[gfoot]

OK, I guess that all sounds about par for the course. To get 50 Kbytes/second I had to send 512 byte packets at short regular intervals (every 12ms or so). Bigger packets or more frequent packets caused corruption - presumably due to overwriting the data before it was properly received.

I'll try to put some stuff in a zip sometime - it might not be much use though.

 

[techFreak]

I got my USB serial connection working with HyperTerminal. I try to send and receive files with ZModem but it takes ages. Transferring 8Kb from PC to GP2X took 2 mins. Isn't it way to long? Am I doing something wrong?

 

[Dr Cain]

I just remember using Ice Zmodem -- and it kicked ass... I did some googling trying to remember thoese bbs days – came across Bi-Modem which sounds like what I remember... Does anybody remember this stuff it's bugging me that I can't...

​

Bi-modem kicked ass when sending files to your friend.. he could also send you files at the same time.. and you could chat during the sending session Those were the days.

 

[bjimba]

I got my USB serial connection working with HyperTerminal. I try to send and receive files with ZModem but it takes ages. Transferring 8Kb from PC to GP2X took 2 mins. Isn't it way to long? Am I doing something wrong?

​

Yes, that's way too long. Even in the worst cases we're talking about, it should a matter of a few seconds. Unfortunately, I don't have a Windows box to test with. I'll see if I can scrounge one up.