Electronics > Repair
LCD image reversed Line6 Helix
Nominal Animal:
--- Quote from: coromonadalix on October 23, 2024, 09:39:51 am ---OP is not under any obligation(s)
--- End quote ---
Technically true, but even plain Game Theory says it is beneficial of OP themselves in the long run to do so for every forum they posted the question about this. Enlightened self-interest and all.
Audiorepair:
I have already stated here, that this is the only forum I have posted to on this subject.
All the relevent info required and the solution to this issue is now easily found on Google, including the part number of the display.
My work is done here, my customer's Helix is repaired, anyone with the same problem will easily find out what to do.
Audiorepair:
--- Quote from: Nominal Animal on October 22, 2024, 06:06:31 pm ---
--- Quote from: Audiorepair on October 22, 2024, 05:52:48 pm ---Thanks for all the help and info, I'm sure someone else with this problem will find this thread now.
--- End quote ---
--- Quote from: Audiorepair on October 22, 2024, 05:52:48 pm ---if this was caused by 2 adjacent ribbon lines shorting, would this happen by manipulating the ribbons and trying to recreate this short after booting, or is this line just polled on startup and ignored subsequently?
--- End quote ---
It is typically sampled at the start of every frame, once every display refresh, so about 60 times a second.
It is absolutely possible to recreate the mirroring by connecting pins 35 and 36 using a suitable resistor. (A strong direct short, say using a screwdriver to poke at the gap between those pins on the daughter card, may create a direct short between the digital VCC and GND, and damage something.) It's just that at 0.5mm pitch, it's beyond my own finger dexterity; if I were to try and do that, I bet something would go Pop! and release the magic smoke...
--- End quote ---
OK so now I am doing this in my own time that the customer is not paying for, I query your assertion above.
I looked at the manual for this display, and on page 19 it gives the power up/power down sequence.
The pin35 you correctly identified as the pin that will flip the display, is designated SHLR.
However it seems, as I postulated, that this pin is polled at Startup as part of the Initialisation process, it is not constantly monitored subsequently.
So no amount of physical stimulation of the ribbon cables after boot up will be able to flip the display, or indeed poking about with a screwdriver as you imply.
This from the data sheet:
Notes: Data include R0~R7, G0~G7, B0~B7, HSD, VSD, DCLK, SHLR, UPDN, DE
MODE, RSTB, STBYB, SHLR, UPDN, DITH
http://static1.1.sqspcdn.com/static/f/489821/26342048/1435254000047/HSD062IDW1-A00.pdf?token=wedVmeycvRpgeAo4dr1NFba11vw%3D
Sorry for the crap image, I couldn't easily find a way to capture the particular PDF page and save it on my home Mac as I do with my Work PC, so I just took a photo on my phone.
I guess I'm used to making the best use of my time.
Nominal Animal:
--- Quote from: Audiorepair on October 26, 2024, 08:32:36 pm ---
--- Quote from: Nominal Animal on October 22, 2024, 06:06:31 pm ---It is typically sampled at the start of every frame, once every display refresh, so about 60 times a second.
--- End quote ---
I looked at the manual for this display, and on page 19 it gives the power up/power down sequence.
The pin35 you correctly identified as the pin that will flip the display, is designated SHLR.
However it seems, as I postulated, that this pin is polled at Startup as part of the Initialisation process, it is not constantly monitored subsequently.
--- End quote ---
HannStar does not specify which controller it uses, and the datasheet isn't exactly clear. In the image 6.5, SHLR and UPDN are not part of the startup or shutdown sequence, but are grouped with "data include R0~R7, G0~G7, B0~B7, HSD, VSD, DCLK, SHLR, UPDN, DE [...] MODE, RSTB, STBYB, DITH". This implies they are continuously sampled, not sampled only at power-up.
The controllers I have used, do sample the polarity/mirroring pins for every frame, including the ST7262E43 I already mentioned. Some, like ST7789V2, do not have such input pins, but do have a command to select orientation and mirroring of the display. The displays like ER-TFT070IPS-4 with ST7277 controllers (that do have such an input pin) do not export that pin to the FFC. These are for 800×480 displays, like the one you have, by the way; I mostly use smaller ones, 320x240 and 480x320 ones.
Perhaps I should have worded that differently, say "in my experience,", instead of "typically", but if you look at display modules with datasheets freely available (ILI9341, ILI9488, ILI9881, ST7701, ST7789, NV3052, NT35510), they definitely allow changing the orientation at runtime via a dedicated command. Perhaps it is an error for me to make any inferences from these to all display modules. :-//
Simply put, in my experience across the various controllers, the direction is sampled at every new frame, and can be switched without turning the display off. It is quite rare for anything to be only sampled by the display controller at power-on, and ignored afterwards: none of the displays I have do that.
--- Quote from: Audiorepair on October 26, 2024, 08:32:36 pm ---So no amount of physical stimulation of the ribbon cables after boot up will be able to flip the display, or indeed poking about with a screwdriver as you imply.
--- End quote ---
Are you sure? Did you verify this in practice, or is this just how you understand the datasheet? In my opinion, the datasheet isn't clear on this. In particular, R0~R7, G0~G7, B0~B7, HSD, VSD, DCLK and DE are the digital video signals, and they definitely aren't simply sampled at power-up; they are continuously sampled, as otherwise the display would be all in single color.
I am not saying it is impossible, I am only saying it would be different to all the display controllers I have. Granted, I don't have that many, maybe a two dozen, but I do have considered and compared the most commonly available openly documented ones, and read their datasheets and pinouts, and examined the open source libraries used to drive these from microcontrollers (which is basically what I do for a hobby, as I've explained above). I myself have plenty of time for my hobby, but only a small budget.
Audiorepair:
Ok, I don't see why any designer would want to include the possibility of LCD flip where such a possibility would never be desirable.
They would surely just wire this out and use the INIT stage to set it as required.
Look, this is pretty much a moot point.
The problem here is clearly to do with dirty ribbon cables, reseating them is the solution.
Problem solved.
There is little point in persuing this any further IMHO.
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