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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9063

Posted: 01:11am 31 Dec 2014

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Hi. Playing around with some things tonight, and one of those was setting the console baudrate.

I set a working 150's baudrate to 115200 with the command OPTION BAUDRATE 115200 and pressed ENTER.

That done, the uM is dead. It will not respond no matter what baudrate I select, no matter how many times I cycle power.

It also will not respond if I short TXD and RXD and apply power - which should wipe any program in memory, and restore the default of 38k4, but it does not.

Anyone else seen this?

EDIT: OK, I reflashed the chip with version 4.5E, and the default of 38k4 baud is working fine, so I typed in the above again, and once again, the chip is inaccessable.

I will now reflash again, and try a slower baudrate.

EDIT: Nope - always locks up with a change in baudrate. Now, the interesting thing is that in the locked up state:

1) Power down
2) Short console TXD and RXD
3) Power up for about 2-3 seconds
4) Power down
5) Remove short and restore console connections

After doing THAT, it wants to talk at 115k2 baud, but with a cleared memory - odd.

Something else odd - does not matter WHAT baudrate I select in TeraTerm - the Micromite always works. So I can select 1200 baud or 115200 baud, and both settings work with the Micromite without any issue.

It should be noted at this point, that I am talking to the uM via a VT100 unit(it's the VideoMite 1A PCB, actually), so does the VT100 do some kind of fancy translation in the background or something?

EDIT: I think it is too late at night.

I still have my baud-rate solder-blobs in place for 38k4, so I am guessing this is the problem, yes? No matter what I set in the VT100 setup screen, with the hard-wired baudrate set to 38k4, it will always be 38k4 no matter what I try to change in the terminal setup screen.

...I only just noticed those blobs setting the baud-rate...

Therefore, setting the uM chip to 115k2, probably WOULD result in nothing at all on the terminal screen, as the baudrate between the uM and the VT100 are so far out, that you can't even seen garbage characters.

Sleepy time now - to be continued tomorrow...Edited by Grogster 2015-01-01

Smoke makes things work. When the smoke gets out, it stops!

Geoffg

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Joined: 06/06/2011
Location: Australia
Posts: 3165

Posted: 04:59pm 31 Dec 2014

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You must have been having a good New Year's eve Grogs !!

The baud rate in the VT100 Terminal is set by the jumpers (A, B and C), not Tera Term. So, when you changed the baudrate on the Micromite, you should have changed the jumpers on the terminal section to match.

BTW, I have just finished building the Videomite and it is a great little board. Everything is there (VGA, keyboard, Micromite, etc) in one neat package and it makes the perfect solution for someone who wants to use the Micromite with a dedicated display. Thanks heaps for the board, very much appreciated.

Geoff,

Geoff Graham - http://geoffg.net

Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9063

Posted: 05:07pm 31 Dec 2014

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You are welcome.

I'm glad you like it.

I am in my 12th week of being sober, so it was not new-year's sauce making me make mistakes!

I have yet to test this out a bit more(the 115k2 thing), but with the solder blobs in place, I am expecting that this was permanently locking the VT100 down to 38k4 regardless of what was set in the SHIFT-F12 menu.

I therefore expect that if I remove all the blobs on A, B and C, I will then be able to set the VT100 and Micromite to match.

Smoke makes things work. When the smoke gets out, it stops!

TassyJim