Erratic operation / Setting expanded mode on a fast PC

[J. Davis]

I have a couple of your 100mm squared 68hc11 boards.
The main one I use has a PRU unit and runs in the expanded mode with Buffalo in eprom, and 2- 8K ram chips.

For the most part the unit works great. When I connect
a ribbon cable from the header pins to a I/O board the unit becomes unstable. This connection would be for ports C,D,E. With just port A and B connected there is no problem at all. It seems related to port E. Sometime
I can get the unit to boot and load code with port E connected but soon as I execute the code I cant ever get a reset to Buffalo and the unit starts making erratic outputs to port A and B.

Do I need any pull up resistors on port C,D,or E if I have a PRU installed?

I do have a spare 68HC11 on the second unit I have that I could try in the main board, but I have lost the information on how to configure the F1 forth chip to expanded mode with the I/O base set to $1000.

Any help would be appreciated,

Jeff Davis

[RMDumse]

I don't have any reference material here to work from, but just from memory, I recall Buffalo looks at a pin when booting to decide whether to run Buffalo, or try to boot a user program. I'd guess that pin is PE0. Further I don't remember if you pull it up (probably) or pull it down to run Buffalo. But you could try each way, and you should be able to figure it out pretty quickly. If it isn't PE0, it's likely one of those pins up there, but I'm fairly certain it's PE0. Try it first at least. You can check this without the ribbon cable attached. Pull it up, hit reset, pull it down, hit reset. The way that gives you Buffalo will be consistent.

As far as Forth on an F1, there might be some confusion, because there is a processor which is an F1 but it doesn't have Forth on it. The Forth is on the E9 or A8. But it can be turned off with a utility called WIPE or WIPE35, which you probably already got from us.

HTH

[J. Davis]

Thanks for the quick response:) I purchased these units
several years ago and it would seem my wife has misplaced the floppy with all the tools that you sent me.... If possible could you email me the standard floppy files for the boards?

After posting, I found another fellow who was having trouble with the PE port using Buff as well so it seems to make sense, Will try your recommendations.

Thanks again,

Jeff Davis

[RMDumse]

I don't have the disks here. Perhaps you could email NMI Technical Dept. [nmitech@newmicros.com] and ask LC to send them to you. (I'll email him to let him know of this thread, but it would be easier if he could just reply to your email in the morning.)

When you find out for sure which pin (PE0?) and which way (up or down) maybe you could post here, so anyone else following this reply would have the answer too. In fact, it might already be on here, I just don't know off hand.

[nmitech]

Yes, The very first thing on power up, Buffalo senses PE0 to run the user application program if PE0 is pulled high. On the other hand, if PE0 pulls low, the Buffalo prompt will sign on and display the buffalo commands on screen. Just make sure you pull down PE0 with a 10K resistor to avoid floating input condition and that can cause the Buffalo to lock itself in the $B600, eeprom when it tried to execute the user application program.

Sound to me J. Davis has a NMIX/T-0021/2(F68HC11FN V3.3 or V3.5 FORTH based) board(s) not a NMIS-0024 (HC11F1 based). Please verify if i am wrong.

I need your email address to email you the WIPE35 program so that you can turn off the Max-FORTH on chip in order to get the default I/O register at $1000 also to be able to run with the buffalo monitor. I could not contact you since you did not have your email address in your profile on the forum.

nmitech@newmicros.com