pbFORTH : 309


Robotics / RCX / pbFORTH / 309	308 \| 310

Subject:	Re: Which terminal on Linux? plus random thoughts.
Newsgroups:	lugnet.robotics.rcx.pbforth
Date:	Thu, 4 May 2000 20:32:01 GMT
Reply-To:	SJM@saynotospamJUDGEMENT.COM
Viewed:	1158 times

Ralph Hempel wrote: > I think that the likelyhood of collisions during a debug session makes > it imperative that the bot's are simply covered when talking to the tower. > > Keep it simple, right :-) I missed that. What do you mean by simply covered. > The protocol you described is shockingly similar to XMODEM, which is tried > and true. No surprise there. I implemented XMODEM a long time ago on a spectrometer. I don't remember the details but obviously it stayed with me. Besides all protocols tend to look the same at the lowest level, especially with the constraing of using 8 bit asynchronous serial data as implemented in common OS'es. Your hands are pretty much tied. You have a framing part that specifies where frames start and end and an error detection part. XMODEM is OK for unidirectional transfer like file upload but is not as strong for bidirectional links. It totally ignores turnaround for example. I might be tempted to use XMODEM as the low level packet format but replace the ACK/NAK with a more useful response, probably a packet with the same low level XMODEM format. Add my address and command bytes in the data section and we are right back to my proposal. > Sergey Udovenko was kind enough to supply XMODEM words > for the last release of pbForth. I missed that. I thought that was going to be in the upcoming release. I guess I got it mixed up with Ernst de Ridder's stuff for code download. Does that use XMODEM? In xsend.txt right? I'll check it out. There's nothing quite as good as code that is already written and tested.

Message has 1 Reply:

		RE: Which terminal on Linux? plus random thoughts.
(...) Umm, I mean cover the tower and the RCX with a box.... :-) (...) No, Ernst's idea has a preamble byte for the transfer, and then the RCX grabs all of the chars and sums them. If the sum is wrong, then it NAKs the packet and the host sends it (...) (24 years ago, 4-May-00, to lugnet.robotics.rcx.pbforth)

Message is in Reply To:

		RE: Which terminal on Linux? plus random thoughts.
(...) I have beta quality Tcl code that sends an SRECORD firmware imge up to the RCX (fast or slow) and has basic terminal capabilities. It also strips comments and whitespace out of files as they are uploaded to reduce the time. I'd like to put a (...) (24 years ago, 4-May-00, to lugnet.robotics.rcx.pbforth)

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