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Grogster
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Posted: 03 December 2017 at 4:35pm | IP Logged Quote Grogster

You are correct - they are. But I expect they are probably using either COM1 or COM2, not the console pins. I may be wrong.

On the 1D PCB, there are no series 1k5 resistors on the console pins. Perhaps that changes things, and perhaps that is something I need to change in version 1D2....

I only ordered 10 new 1D boards, so I could always change this for the next batch.

Rob will be able to clarify exactly what the situation is here. If he reads this post, he might add his thoughts. I will point him to this thread.

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robert.rozee
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Posted: 03 December 2017 at 5:10pm | IP Logged Quote robert.rozee

my inclination is towards including the series resistors - doing so does no harm, while possibly being very useful if needed. with the E28 in particular, they allow for access to the console even if the (soldered in place) 1455 becomes non-functional.

i've not looked too closely at the E100, can the console pins be fully isolated if the 1455 and CP2102 module are unplugged? what if the 1455 is soldered in place?


cheers,
rob :-)
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Grogster
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Posted: 04 December 2017 at 7:19am | IP Logged Quote Grogster

Hi Rob. Thanks for chiming in.

On the E100, CON6 is connected DIRECTLY to the PIC32 console pins.
If the 1455 chip is NOT installed, the board fuctions exactly as the earlier boards in that CON6 is your console, or you can put a CP2102 USB module on that footprint and use a USB connection to the console that way.

If you plug in the 1455, it is then connected in-circuit to the PIC32 console pins, but a direct pin-to-pin connection - no series 1k5's. As an afterthought, I could add these in if you thought it would be worthwhile - for the next batch of boards. I only got ten of the 1D's so I can check they are a viable design before getting too carried away buying in boards!

My primary concern is that if someone installs a 1455, and then tries to use a CP2102 at the same time kind of idea - would probably cause all kinds of hell.....

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robert.rozee
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Posted: 04 December 2017 at 9:23am | IP Logged Quote robert.rozee

you could look at putting in 1k5 series resistors for both the 1455 and CP2102 module? i guess it depends to what extent you want to try and stop folks from doing silly things!

cheers,
rob :-)
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Posted: 04 December 2017 at 9:52am | IP Logged Quote Alastair

re the possible contention between 1455/CP2102. Haven't seen a schematic but could you squeeze in a simple jumper so that the two could not be connected to the console pins at the same time. Not only electrically makes it easier but also its presence makes it obvious it is either/or.

Otherwise need to assume a knowledgeable user.


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Grogster
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Posted: 04 December 2017 at 2:05pm | IP Logged Quote Grogster

Thanks guys - good suggestions both. I like Alistair's idea. I might see if I can find a suitable PCB DPDT slide-switch. But then you have the PIC32's ICSP header connected to the 1455 and probably should deal with that too. Anyone know of any 4PDT PCB slide-switches? (rhetorical!)

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Azure
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Posted: 04 December 2017 at 3:42pm | IP Logged Quote Azure

You could just add 3 way 0.1" pads to Con6 pin and 1455 pin either side with centre going to PIC pin. Do it twice for both Tx/Rx and make the pads suitable to solder a bridge or SMD 0805 0R between them.

That way most options are covered, jumpers if full flexibility needed or shorted pad if configuring for fixed setup to Con6 or 1455.

That is what you have probably already done anyway :)
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Posted: 05 December 2017 at 6:29am | IP Logged Quote chronic

You could use a mcp2221a instead of the 1455 or 2102 - it has the 1455 pinout
and is cheap
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Geoffg
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Posted: 05 December 2017 at 11:40pm | IP Logged Quote Geoffg

I have received a number reports of corrupted colors or text with the E100.

This seems to be caused by the current drawn by the backlight which can cause a voltage drop on the ground pin which can in turn shift the logic levels as seen by the display controller resulting in corrupted colours or text. An easy way of diagnosing this effect is to reduce the CPU speed to (say) 40MHz. If this fixes the problem it is a strong indication that this is the cause. One fix is to solder power and ground wires direct to the LCD display panelís PCB.

I was wondering if beefing up the amount of copper leading to these pins on the E100 PCB might also help. Perhaps something for the next revision.

Geoff
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lew247
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Posted: 06 December 2017 at 5:28am | IP Logged Quote lew247

What pin number does the F_CS on the LCD connector go to? (version B board but I assume it hasn't changed) I "think " it's 58?

Edited by lew247 on 06 December 2017 at 5:33am
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Posted: 06 December 2017 at 7:34am | IP Logged Quote Grogster

@ Geoff - Yes, I have seen that problem myself in projects of my own on the E100. I dropped the CPU speed to 80MHz and the problem went away. Did you have specific ground pins in mind for beefing up? I guess definitely around the LCD connection and maybe the regulator. Peter(matherp) has already fixed his issues there by hacking the LCD display to use 5v rail. I personally like this idea the most, but the problem is that not everyone would be happy doing it.

I wonder if running a thick-ish wire from the LCD ground DIRECTLY to the regulator ground on the rear of the PCB would help that issue? A nice easy fix, and anyone can do it....

@ Lew - Pin58. No, this has not changed.

EDIT: OK, I have beefed up the copper to the 3v3 rail and ground. They were 0.8mm, they are now 1.5mm. I have duplicated the 0.8mm copper track to the 3v3 rail on the top and bottom copper and joined them to the 1.5mm supply rail with an exposed via that you fill with solder as part of assembly. That should help for the next lot of boards with any luck.





One thing I can't remember is that the pin labelled "nc" on the 5" LCD seems to have a 3v3 supply rail connected to it on one of the internal layers, but I don't remember why. Geoff or matherp will remember why. Can one of you gents remind me?

EDIT: This track here. Light brown, connected to third pin down from the top on the left, legend says "nc" for no-connection.





EDIT: Ohhhh, wait a minute..... I think that 3v3 connection is for the 7" LCD's if you elect to use one with the E100 mainboard. On the 5" LCD it is indeed no-connection so goes nowhere. Might therefore beef up that connection too.

Edited by Grogster on 06 December 2017 at 7:53am


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