It may be because English is not my native language but I have to say : The LCD part of the CORE_STM32F4 Module page is not clear at all. Because of that (and because I didn’t take the time to check the VCC and Ground BEFORE soldering) my LCD have made this typical sound of… fire starting.
But after that… the wire 3 is NOT V0. So the sentence “Order of wires is matching with flat ribbon cable” doesn’t work. And I can’t figure out how it can work (with the J15 port at his place). For me all the wire have to be twisted two by two. It’s too cold is the garage right now, i will try tomorrow.
Multimeter in “bip if wire” position. V0 is not in the wire 3 but the wire 4. Sorry I didn’t check my messages before posting (baby things to do…) And forgot to mention it.
Yeah the pinout of the LCD is very clear and written on the PCB. The problem is one the other side, as I have the big black plastic of the ribbon port that hide all the important information written one the core PCB. Had to remove it to check… After the fire.
The LCD is probably dead (in French: le son (juste le son) d’un petit feu qui crépite est mauvais signe, la nouvelle odeur aussi, mais je testerais le nouveau câblage… Au cas où) but yes, I have an other one ! Lucky me…
Ok this is not the cause of “the new smell” cause you just send a voltage between 0 and Vdd to the RS pin. sending core RS Pin to LCD V0 is worst, hope it’s your LCD which smells not your core.
Try another LCD and check all wires this time, check also for short circuit between adjacent pin if you’ve got the time and you’re not sure of your ribbon. A bad crimping happens to me recently
1 hour ago, Hawkeye said:
Welcome to MIDIbox!
Yes! Welcome to this new world of sound… and smell lol
Thank you both of you ! In fact I’m an old newbie here. My core was made in 2016 (edit: the metadata of my pictures says October 2017), and I follow uCApps for more years than that ! Maybe 2004 (… Wow.. so long ?..).
It’s okay for me to broke an LCD, but the point here is about the indication on the website, they are confusing about the ports of the STM32F4. I mean… Really.
But on the other hand, I should have double checked the vcc and ground for sure.
(Wire 1 and 2 swapped, 3 and 4 swapped, and so on)
That sounds like a cabling issue to me. You probably crimped the cable the wrong way round (or used a cable that was crimped the wrong way without you noticing).
I’m back from the garage. It’s -1°C … cold. Anyway here is a google album with the pictures i have taken, just under the midi-notes attribution chart: https://photos.app.goo.gl/5bR4r2ivZe5dgYYW9
You can see where is the notch of the ribbon head, the big clear labels on the LCD PCB, the labels hidden under the “big black plastic of the ribbon port that hide” and finally, how I test and found where the V0 is.
Please not that I’ve tried to de-crimp the ribbon yesterday, but it was well crimped before the incident.
We can clearly see on your pictures that VDD goes to ground(Vs) and VSS to Vd, just follow the red stripe !
In fact, I think all is reversed by pair! You have to unsolder the ribbon on lcd side and solder wire 1(red) to pin 2(Vd), wire 2 to pin 1(Vs), wire 3 to pin 4(RS), wire 4 to (V0)… et ainsi desuite…
Thus the pin numbering starts at 01 in the bottom right corner.
Could you check that these pin numbers correspond to those on the LCD when the cable is connected (with the power off)? Or are the pairs inverted as Bruno says?
Otherwise the pinning on the LCD (unless it’s mislabeled) looks to correspond to the Hitachi standard.
Yes, this is what I think and write earlier. That the first reason why I’m in this particular sub-forum… There may be something really unclear about the “mirror” thing on the documentation page.
Just now, latigid on said:
Could you check that these pin numbers correspond to those on the LCD when the cable is connected (with the power off)? Or are the pairs inverted as Bruno says?
The multimeter as show say “it doesn’t”. The V0 “bip” on the wire 4.
And I can’t mechanically change this order can I ? The red strip of my ribbon will always be clamped to the top right of this schematic (The last wire will alway be at the bottom left too).
The two opposite side of ribbon cable will alway be in diagonal, top right / bottom left as i understand. Did I miss something ?
And I can’t mechanically change this order can I ?
Sure you can, you have crimped the connector to the cable the wrong way round. There is a little marking in the form of a triangle on the connector - this should match the red wire, as it marks pin 1. It looks as if you have ignored this.
