I am looking to use a round AMOLED display with an ESP32 and have found 2 basic options (with a 3rd that is slightly different). I have found some displays based on an RM display driver (such as this: https://www.alibaba.com/product-detail/1-39-inch-ips-454x454-rohs_.html) which seems to support MIPI and SPI, which seems to be backed up by the vague pinouts I have seen that have SPI labled pins. The other lookks to be driven by an RM display driver that only appears to have MIPI pinouts and so wouldn't be suitable to be used with an ESP32. As another option there is something like this larger screen that appears to support SPI/RGB: https://www.szmaclight.com/product/round-lcd-display-2-1-tft-480x480-RGB.html
One problem I am running into is that I cannot find a datasheet for the RM, or any written drivers, which would make it very difficult to use the screen.
Apologies for reviving an old thread, but I've recently been going down this same path, as you can find those AMOLED screens for < $20 shipped, which would make them amazing for ESP32 projects if possible to connect and drive them.I've had a little luck tracking down some info so I figured I'd share what I've found so far in case it's useful to others.I got a RM "User Guide" from messaging a seller on Ali and asking for datasheets, though it seems to be focused on manufacturers of displays as the "user" rather than application engineers. As far as I can tell it's mainly documentation of a bunch of registers (that I believe are one-time-programmable?) for things like panel configuration, charge pump settings, etc. Generally it does not seem useful to me, as I assume the drivers should already have these values programmed appropriately by the panel manufacturer.Of more interest though, I noticed that Ambiq had published release notes for their SDK indicating they added driver support for RM, which led me to finding this driver implementation for Ambiq MCUs which uses SPI. There's a lot of potentially good stuff there (and in the .h file) including code that initializes the driver IC, and there's good documentation about how to configure SPI. I'm not familiar with Ambiq's SDK, but if I'm reading it correctly, I think I'm seeing several different configurations for either single SPI () or quad SPI (). One potential concern I see is that their driver sets the SPI clock to 48MHz, which is a bit daunting to me in terms of data integrity if I throw together a cheap test PCB, but since it's SPI, it would hopefully be possible to just slow that down to something more hobbyist friendly while initially trying to get it to work.There seem to be multiple similar models of 1.39" AMOLED panels based on the RM driver available, so for clarity, I'm focusing on the panel that's marketed as a Huawei GT2 46mm smart watch screen replacement, which came marked "FPWA" but I believe also can be found as "wb014znm-t00-6dp0". These panels seem pretty readily available, and also come bonded to glass/bezel and includes a touch digitizer, which would be useful in the future if I can ever get the display working. One difference I've seen on spec sheets for similar displays is the connector. Some datasheets I've come across seem to indicate a YXT-BB1F connector with a 0.4mm pitch, but the GT2 46mm display connector appears to be 0.35mm pitch using calipers, and if the spec sheet I found is the correct one, that would be a BM28U-24DP_2-0.35V(86)_2D_SPE connector. I've got the mating connector on the way from digikey, and will update when I find out whether it's correct or not.For that specific model of display, and again assuming I'm looking at the correct spec sheet, a few things stood out to me:Still seems like an uphill battle to get this working without additional documentation, but I will try to keep making progress. If the connector I ordered works, my next step will probably be to spin a quick breakout PCB for the connector and level shifters based on the pinout in the spec sheet I found... If the connector doesn't work it's back to scouring the internet for more clues...
Over the past few years, display technology has progressed in various ways, leading to more options for gorgeous displays that make your finished product appealing and straightforward to use.
The decision to use a display that still looks beautiful after years of use, however, is what helps you create your reputation and retain customers if your end product must work in challenging situations. With our previous blog, OLED DISPLAYS: AMOLED VS PMOLED, we had the option to explore, i.e., OLED.
OLEDs differ from Liquid Crystal Displays (LCDs) in that each diode can be fully disabled, producing a pitch-black display. A backlight is necessary for LCDs (often LED or fluorescent), and the light shines through the LCD to create a color image on the display screen underneath the glass.
OLED screens are more svelte than LCD ones. Since no power is supplied to OLED pixels that display black, the power savings for OLED are seen when an OLED screen shows an always-on clock against a background of darkness. Thus, a &#;dark&#; theme for wallpaper and other elements will conserve battery life for smartphones with OLED screens.
OLED is a revolutionary technology noted for its thin, compelling, and bright displays. OLEDs are categorized into two types.
i). AMOLED
ii).PMOLED
Let us learn more about the types
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AMOLED stands for Active Matrix OLED. There are no display size limitations with AMOLED. AMOLED uses a lot less energy than other display technologies. Incredible performance is offered by AMOLED display providers. Unlike other display technologies like LED or LCD, it is more flexible, lighter, and thinner.
Because the AMOLED is TFT driven and has a storage capacitor, it can display big displays with high resolution. Since AMOLEDs have a storage capacity and can display high resolutions more easily than PMOLEDs, they can be easily regulated. They have no storage or resolution limitations at all.
Due to its exceptional performance, smartphones, computers, and televisions frequently utilize AMOLED.
PMOLED stands for Passive-Matrix OLED, which depends on how the display is driven or controlled. A PMOLED has a straightforward control method that progressively controls each display row (or line) (one at a time).
You can control each and every line of the PMOLED display&#;s on-screen display using its control scheme (one by one). Since there is no storing capacitor within, the majority of the pixels in the lines are off.
You must utilize extra voltage in order to make the display brighter and account for it. For instance, if you have 10 lines, you must complete each line 10 times as bright. The number of lines may vary depending on the display needed, but an average ratio is needed to highlight the lines.
Although inexpensive, they are also simple to build and less effective than anticipated.
Microtips Technology is a major OLED display manufacturer situated in the United States. In , the business unveiled a 1.39-inch round AMOLED display with a 400 x 400-pixel resolution. Additionally, their 5.49&#;&#; AMOLED Display Module (Microtips MTDAZOM-T), which offers a resolution of (RGB) x , has significantly contributed to the field of OLEDs. A sizable audience has lavishly complimented each of the improvements.
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