[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [N8VEM-S100:5901] Propeller Console I/O

Josh, what baud rate is your UART com port running at?

A 33% increase in speed by dropping the communications to/from the serial terminal doesn’t sound like much over, say, 9600 baud. 

But if you are already running it pretty fast (like 57,600), then a 33% increase is significant.


A couple of years ago, I modified my CPM2.2 BIOS (and boot loader and monitor ROM) to work just as you describe – with at least one, but possibly two consoles, both working in parallel.  My motivation was so I would continue to have access to my system in the event that the Fulcrum Computer Intelligent Video Interface (IVI), which is an S-100 terminal on a board, and which runs very fast – about the equivalent of 100,000 baud, would die.


I’m guessing that the Propeller board is similar is speed and function to my IVI, just modern design and hardware as opposed to the 8085 and 8275 components of my board.




Bob Bell



From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Crusty OMO
Sent: Sunday, December 28, 2014 3:58 PM
To: n8vem...@googlegroups.com
Subject: RE: [N8VEM-S100:5901] Propeller Console I/O


Hi Guys,

Ok, I fixed a small "oops" in the version 2.0 firmware.  You can now find v2.1 in the wiki pages at:


I was sending characters to both the UART Com-Port and the Propeller Board to give dual support.
The sending process was being governed by the UART... I figured if the UART was empty and ready for the next character, then why shouldn't the Propeller board?  Well, I was wrong, the propeller's ready signal must always be checked, not only for flow control, but because it might be in the middle of a refresh cycle.

Version 2.1 corrects this.  The good thing here, is you need only copy the BIOS-v21.HEX file to the SD card as 'BIOS.HEX' and use the same v2.0 boot loader.

Just for fun, I thought it would be nice to see how fast the Propeller I/O board can work without the dual support to the UART Com-Port.  So, I created a version 2.2 (uploaded as a supplemental) that talks ONLY to the Propeller board.  Result is a 33% increase in console output speed.

If you like, you can copy both BIOS hex files to the SD card.  The system will automatically boot from the "BIOS.HEX" file, but if you like, you can press "D" during the boot loader menu and enter the name of the other BIOS-vXX.HEX file.  Yes, you can eat your cake and have it too!

Josh Bensadon

You received this message because you are subscribed to the Google Groups "N8VEM-S100" group.
To unsubscribe from this group and stop receiving emails from it, send an email to n8vem-s100+...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.