[Solved] Can't get Lumex OLED 16x2 and 20x4 character displays to work. - Page 1
Forum section: electronics / beginners

author: Whales
author_rank: Super Contributor
timestamp: February 10, 2020, 02:56:50 am
content: I can't get these modules to make any light at all (not even a flicker or a pixel).Larger: LOD-H02004DP-GSmaller: LOD-H01602DP/A-YThe datasheets (attached example) are extremely sparse, only mentioning some rough parameters and pinout:These modules look like standard 16x2 and 20x4 LCD modules (akaHitachi 44780 style), but with no contrast control (N/C) and no external backlight control ('PLEASE NC'). The latter seems to be because the boards have an in-built 5->12VDC boost converter -- I've measured pin 15 to be at 12V once the unit is powered, so I've left the last two pins unconnected.Using the standard Arduino LiquidCrystal library I am able to drive an old 16x1 LCD I have sitting around, but switching those same wires over to one of these OLED units results in nil. Tried both 8-bit and 4-bit modes. Tried an older version of the LiquidCrystal library that was rumoured to be slower. Tried manually (jumper wires + buttons) clocking commands in, but for I all know I may have made mistakes doing this. Seems like nothing makes the display turn on.These modules use a US2066 controller. Datasheet (attached) is pretty sparse on command information, so I again presume it's a Hitachi HD44780-compatible thing. It does support non-parallel modes (I2C and serial) however some of these modes require grounding a pin I do not have access to. I tried an I2C scanner anyway without any luck.Digikey currently lists these displaysas 8-bit parallel mode configured anyway.Not familiar with I2C, maybe there is a better way of determining if it's so (any particular lines/patterns I can scope and expect to see traffic on power-on?)Otherwise: am I missing something silly? Anyone ever used these modules before?N.B. bought these years ago from Element14 because they were cheap (badly selling?) stock. Would Lumex care enough about me to answer an email? Might be worth a try.

author: MarkF
author_rank: Super Contributor
timestamp: February 10, 2020, 05:28:23 am
content: It appears they are configured for "MCU Parallel 6800 Interface".-Section 5.1.1shows the timing diagram.-Chapter 7shows the command set.1) Connect it to your Arduino (5V logic)2) Read the datasheet3) And GET to work writing codeI did it for a color OLED (SSD1351). It is not that hard!You don't even have to build a font.

author: Whales
author_rank: Super Contributor
timestamp: February 10, 2020, 05:53:49 am
content: I'm glad that there's a good chance I'm a fool and that my parts are OK. Thankyou MarkF.QuoteWhat. WHAT. Have I been using an abbrev form of that file... I do not enjoy the flu.EDIT: this thing even has photos of the screen under test. I think I've been working off a shorter/truncated form and only found this version to attach when I went to my other computer. Or I'm just silly old me. I was seriously struggling to find anything more than some vague timing diagrams.

author: Whales
author_rank: Super Contributor
timestamp: February 10, 2020, 07:29:18 am
content: Solved. Re-jumpered my unit to talk in 8080 8-bit.These things are really pretty.Thankyou MarkF.

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2020, 02:57:47 pm
content: Why don’t you list how you had to configure the jumpers, for anyone else who may google this topic and find this thread?

author: Whales
author_rank: Super Contributor
timestamp: February 10, 2020, 10:46:12 pm
content: No.I want others to suffer. Wait no, I mean the flu, not these screens.On the rear of these screens are three 0-ohm jumpers labelled J0, J1 and J2. Ignore all of the other jumpers: these ones are the BS[2:0] jumper pins mentioned in the US2066 datasheet (table 4-2 on page 3 or 4).In the photos they're jumpered for 100 (8-bit 6800 parallel), I changed them to 110 (8-bit 8080 parallel). This is what most Arduino libraries and reference materials assume/use for talking to character LCDs.These displays apparently also support serial & I2C modes directly with the right jumpers, I'm going to try those next (that's what I intended to turn these into anyway using an external board).