Driving LCDs with Microcontrollers (Arduino) using LCD Drivers (AY0438)
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- čas přidán 5. 08. 2024
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So I got myself some 3½ digit non-multiplexed LCDs (link below). And of course I wanted to display some numbers on them using my Arduino Nano. It was easy enough to find a suitable driver. So let’s start from there.
First I have a detailed look at the driver. It having a CMOS interface some bit banging with the Arduino follows. Then it’s time to address segments and finally to display numbers.
00:00 Intro - a nice LCD, but how to drive it with a microcontroller?
02:26 AY0438 LCD driver - its internals, how to wire it and how to drive it
12:43 Bit banging - the driver’s data, clock and load pins with an Arduino
21:21 Remarks - on daisy chaining AY0438s and the AY0438 Arduino library
26:21 Mapping pins - of the LCD and the AY0438 in software
31:58 Displaying numbers - by extracting numerals and mapping to segments
39:03 Power consumption - is low and measured in μA
39:39 AY0438 "AC" generation - without negative voltages to ground
Tutorials: • Tutorials
Mailbag: 3½ and 4 Digit LCDs (Tested), Thermocouple Connectors and More: • Mailbag: 3½ and 4 Digi...
My Arduino code drive.google.com/drive/folder...
#robertssmorgasbord #tutorials #tutorial #how-to #LCD #driver #microcontroller #MCU #Arduino #AY0438 - Věda a technologie
Don't know what I expected but I definitely didn't expect that to be so easy. Awesome.
Before that project, driving "naked" LCDs appeared to be black magic to me too. But with a suitable LCD driver chip it's really not that hard.
@@robertssmorgasbord with the driver chip from the video it's as easy as pushing data in a shift register. Literally. I think I'll use them for low power projects in terms of current consumption and available computing/serial ports.
@@bastiannenke9613 Yes, literally (the shift register thing) 🙂 And yes, low power: I bought these controllers and LCDs for a battery powered multi-channel temperature meter (4 x MAX6675/DS18B20). But I got sidetracked and now they're waiting for some other use.
@@robertssmorgasbord happens me too sometimes. There is way too much interesting stuff and not much time.
@@bastiannenke9613 Exactly 🙂
LIke data-table-driven logic.
Yes, indeed 🙂 In the good old days you would have used a ROM or a PROM.
Thanks a lot,
Iit's good to share the code.
Regards.
You're welcome!
Cool. I hope I can fix my Viewsonic 17" LCD which flicker every 15 seconds after 30 minutes of being ON. I replaced all capacitors but it still flickers. Where should I check next?
Also the OLED of my Wacom Intuos won't turn ON (it used to display a display but some lines are missing), what should I check on that Wacom's OLED section/module?
Thank you.
God bless, Rev. 21:4
Sorry, but it's a big leap from building a little circuit with a segmented LCD display to repairing high resolution LCD and OLED displays. The only high resolution LCD I've repaired myself was a Samsung SyncMaster 214T (replaced the caps like you did).
Anyway, which Viewsonic 17'' LCD is it exactly? I don't even know if your LCD has a fluorescence (high voltage) or LED backlight. The flickering is usually a sign of the (fluorescence) backlight power supply failing. Since you already replaced all caps I'm all out of ideas.
Regarding the Wacom Intuos: Same Question: What Wacom Intuos model is it exactly (S, M, ...)? If lines are missing in a LCD/OLED display, some connections for driving the lines/columns might be broken. Look for the connections of any flat-flex cables with a lot of wires going from the board to the display.
Hello Dr.Robert , Is there any place where you have a datasheet for the pinouts of the LCD ? AY0438 has become crazy expensive !!
Hi (and I'm no Dr., just a Dipl.-Inf. 🙂 ), I've uploaded the meager documentation for the LCDs to my Google drive:
drive.google.com/file/d/1Egksg7_dV6hHSUrRnVB4o3QrOsVJZqZ9/view?usp=share_link
drive.google.com/file/d/191tQHa_o3u6nO_hhMae_pROsSBsD0TKp/view?usp=share_link
Hope that helps.
@@robertssmorgasbord Vielen Danke. There seems to be a Holtek offering for similar called HT1621. Just FYI .
@@mumbaiverve2307 Gerne geschehen 🙂 And thanks for the info! That Holtek chip is quite nice.
@@robertssmorgasbord Been struggling with HT1621... Well nothing is coming on the LCD display 🙂 . In the datasheet they mention 1/2 or 1/3 bias; 1/2 , 1/3 , 1/4 LCD duty cycle do you know any idea about it ? Also the chip has 4COM pins , while the LCD has only 1 ( Both COM on LCD is internally connected) , so can I leave the 3COM on the chip floating ? Just in case you get some time , any suggestions ?
Ok sorted,.Pins wrongly connected. As usual a case of looking for sophisticated issues while the obvious ones are neglected . Thank you and happy YouTubing
what is the name or specification of the lcd?
It's a no-name product from China. For my sources see the related mailbag video:
Mailbag: 3½ and 4 Digit LCDs (Tested), Thermocouple Connectors and More czcams.com/video/FwDqEmZu9Ww/video.html
Hello, I need a specially designed monochrome tn screen, I want to have it produced, but I cannot have it produced because I do not know how to draw or design it. Can you help me?
Well, unfortunately no. I never designed a TN LCD in my life. Are you sure you wanna go down that route? What chip will you use to drive your custom TN LCD?
@@robertssmorgasbordI'm thinking of using one of these chips, UC1671 IC or CN91C4S48 I2C
@@kadiraynur2636 Didn't ad hoc find a datasheet for the CN91C4S48 (seems to be used on a lot of Chinese LCD modules), but I had a look into the UC1671 datasheet - seems to be a quite capable chip. Anyway, good luck with your project!
thanks
@@kadiraynur2636 You're welcome!
Thanks a lot
Can you share circuit diagram with us please?
I've never created a circuit diagram in any software for that video. But I've created one sometime ago for 4 LCDs. If I can find it again I'll upload it and publish a link here.
@@robertssmorgasbord ok thanks
one more question : did you connect the COM pins to the GROUND or 5V? İ have a vım-878 lcd and it has a 4 COM port, so i am confused.
@@osmanozdemir4367 The LCD COM pin(s) are neither connected to ground or 5V! They are to be connected to the BP pin (30) of the AY0438! Also, it's sufficient to connect only one COM pin of the LCD. Still searching for that circuit diagram ...
@@robertssmorgasbord i got it, thanks for your answers
😀
Thanks!
Nice, can you share the code please ?
Uh, I hope I can still find it. If I do I'll upload it to my Google Drive and publish a link here.
Found the code :-) You can access it on my Google Drive: drive.google.com/drive/folders/1fuFXEvtTfkzIPaH96zMdSInuGgUs8282?usp=sharing
@@robertssmorgasbord Perfect, thank you
@@karimguet5967 You're welcome!
Why you sound like mr bean sometimes
Well, I'm not trying to sound funny, but it is what it is 😅