20x4 OLED - how to connect in 'SPI mode'? - Page 1
Forum section: electronics / beginners

author: aurel9x1
author_rank: Contributor
timestamp: August 08, 2020, 01:25:08 pm
content: Hi,I wish to order an OLED Display like this:https://www.raystar-optronics.com/oled-character-display-module/20x4-oled-display.htmlI can't find anything in the datasheet about SPI mode. I understand that it works by default in 6800 mode, but it can be also used in SPI. In the pictures I can't see any jumper to switch.Anybody used this kind of display? How can it be interfaced in SPI mode? What is the pinout and if is there any jumper/setting that should be performed?Thank you.

author: dtodorov
author_rank: Contributor
timestamp: August 08, 2020, 01:38:17 pm
content: Hi there,not sure if this RS0010 IC even supports any type of SPI. From a really quick scan of thedatasheet(if that's the one), I think it's mostly compatible with HD44780 interface that supports 4/8bit parallel transmission.Maybe you can also post pictures of the underside of the boards, typically for LCD displays there are footprints for charge pumps and other jumpers. In this case there could be some SPI IO expander or another IC that does the SPI bridge.Cheers,Dimitar

author: Skashkash
author_rank: Regular Contributor
timestamp: August 08, 2020, 01:45:14 pm
content: You'll need to contact the manufacturer and get the full data sheet for that display to see if it's possible. That summary data/spec sheet they post on the product page just does not have enough info.It's annoying when a company makes you jump through hoops to get a useful data sheet.

author: hugo
author_rank: Regular Contributor
timestamp: August 08, 2020, 02:54:51 pm
content: It seems like it only has a HD44780 compatible controller.

author: wraper
author_rank: Unknown
timestamp: August 08, 2020, 02:56:05 pm
content: Quote from: hugo on August 08, 2020, 02:54:51 pmNope, controller supports SPI. Look at the last few pages of controller datasheet.Quote

author: up8051
author_rank: Frequent Contributor
timestamp: August 08, 2020, 05:45:43 pm
content: See this document for details:https://ep.com.pl/files/9292.pdfIn Polish, but pictures explain everything

author: aurel9x1
author_rank: Contributor
timestamp: August 08, 2020, 07:30:14 pm
content: The link fromup8051solved the problem.Thank you.

author: hugo
author_rank: Regular Contributor
timestamp: August 08, 2020, 09:45:12 pm
content: Quote from: up8051 on August 08, 2020, 05:45:43 pmThat's a different one I guess (it's a Winstar model and supports SPI) however the op asks about a Raystar OLED display...

author: aurel9x1
author_rank: Contributor
timestamp: August 08, 2020, 10:12:05 pm
content: They are using the same controller and I hope will be similar.//on the other hand, I can't understand why it is so difficult to find big OLED screens and when I find one, it is really expensive.There is an 0.96'' oled display which is sold everywhere for 1USD (when I say everywhere, it means EVERYWHERE, in all the countries on the planet, in almost any electronics shop on the planet - the same size, same model).But looking for let's say 3''x3'' oled displays, price goes up 30 times and you can order it only in a couple of shops on the planet.If they can build an 1'', why is so difficult to build a 3'' ones? Why does it cost sometimes even 100times more?

author: Nusa
author_rank: Super Contributor
timestamp: August 08, 2020, 10:34:01 pm
content: Very cool, I didn't know that there was a compatible controller that supported SPI natively. The typical solution for HD44780 type displays is to use a cheap backpack board to get an I2C, SPI, or UART interface.

author: aurel9x1
author_rank: Contributor
timestamp: August 10, 2020, 12:02:44 am
content: Does anybody know why almost all the screens available on the market for hobbyists are about 2'' in size?A lot of arduino projects run on 0.96'' display (as big as a coin), this screen is for kindergarten, not for grown up adults.I am looking for a proper screen for a clock (let's say 10cm x 10cm) and I am unable to find anything. All I can find is about 2.5cm diagonal (as big as my fingernail). Basically there is nothing I can display on this small screens, except 2-3 words. And even if I manage to display more, the characters are so small that it looks like a joke.I want a REAL display, as in cars, tablets and everywhere else where 20'' display is not uncommon.Why can't I find anything like that for a couple of bucks? When I finally manage to find a big display, they asks for 100USD or more, but similar displays are installed in many tablets that costs 60USD and is an entire tablet (including shipping), not only the screen.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: August 10, 2020, 01:37:55 am
content: Use a 16 bit serial shift register 74F675. Use 8 bits for data and the other 8 as necessary for control. Run your SPI in 16 bit mode if available. I did this for a 4x20 LCD and it works great. You’ll need to have a good handle on the data sheet for your OLED.

author: Nusa
author_rank: Super Contributor
timestamp: August 10, 2020, 03:12:13 pm
content: Quote from: aurel9x1 on August 10, 2020, 12:02:44 amYou mean something like this?:https://www.aliexpress.com/item/32908649887.htmlAs you note, it often is easiest for a hobbyist to obtain a new/used/broken mass-marketed device and strip out the parts you want. Although in the case of a working tablet, you could turn that into a very smart clock just with software.