Wanted: a 21st century replacement for the plain vanilla HD44780 1602 LCD Module - Page 1
Forum section: electronics / projects

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 30, 2015, 04:04:22 pm
content: In the last 15 years or so I always used one of these 1602 LCD modules if I wanted some kind of text display in a µC project.They are dirt cheap, robust and have a relatively low pin count (4bit mode). At least the newer versions (white on blue) have a pretty good contrast and readability.However, they are somewhat slow on the display side (fast changing values are barely readable), the communication needs bit-banging (no HW/DMA solution like for SPI) and they are not very flexible (only 8 programmable characters or so).Last but not least, for some bizarre reason, the connector is (nearly) always on top. So while you can mount the LCD directly to a PCB with a right angle header for a front plate display, it will than be bottom up.Anyway, for my next project, 16x2 characters seem a bit limiting, so I'm in the market for a new default display with good availability (also for the years to come), low price (<10€, the lower the better), low pin count (SPI preferred) and easy mounting option (ideally, a pin header to mount to the PCB with a right angle header). E.g. a bare panel with flat connector is not what I'm after. I don't really need color, just a good contrast. Resolution can be low (like 128x64), for higher resolutions, the display must have its own display buffer.Now if you need more than 4 lines, the next obvious choice would be a 1604 or 2004, but this quite an increase in price and they share all the issues I have with the 1602 - including the bottom up problem.For only a bit more you also get a 12864 (128x64) graphic LCD which has a nice size and doesn't have the bottom up issue. Monochrome display and the low resolution is perfectly fine as you don't have much RAM for a screenbuffer in a small µC anyway.Then again, it's the same old technology as the 1602 with the same bit banging low level interface. Plus the whole programming (two rows because of two controllers etc.) is a bit clumsy.Next option is a Nokia 5110/3310 display. They are cheap, easy to mount and support SPI.Yet they are very small and have a somewhat low contrast. Last but not least, they are not produced any more and refurbished from used Nokias. So it's questionable if you still can buy them in a few years.OLED displays are very bright, come in nice (low) resolutions and usually support SPI, but the affordable ones are too small for my purposes. Besides they tend to burn in (-> need to invert the display now and then) and have a limited lifespan.Finally, there are 2,2" SPI 320x240 LCDs with ILI9340/ILI9341 controllers. They are available for less than a 12864 (~6€), which is rather intriguing. The controller is a bit complex, but there are libraries and a simple bitmap/font blitting should be doable anyway. My main issue is that the connector is on the side, so for PCB mouting, you either need to mount it vertically or use a small PCB as some kind of riser board.Currently, I tend to use the latter (320x240 SPI LCD) option even though I wouldn't use either the 256k colors nor the SD card on its back. Still, from a mounting point if view, I'd prefer the 12864 monochrome display.Any options I overlooked? What are you using?

author: helius
author_rank: Super Contributor
timestamp: January 30, 2015, 04:15:31 pm
content: I didn't see you mention Sharp's "Memory LCDs", they're worth a look.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 30, 2015, 04:21:14 pm
content: Not exactly my idea of cheap (i.e. <10€) I fear.Also looks like e-Paper, which is cool for special applications, but usually not fast enough for a general purpose display to show values that change all the time.Besides e-Paper usually needs inverted display now and then to not lose contrast.

author: donotdespisethesnake
author_rank: Super Contributor
timestamp: January 30, 2015, 05:02:52 pm
content: I have been looking for something similar, cheap but an "improved" 20x4. There does not seem to be much between 20x4 and 2.2" TFT.There are some 20x4 display with bottom connectors, e.g.Ebay : 20x4-LCD-Character-Module-DisplayFor a hobby project I am planning to use 2.4" screen with an STM32F4 series, the external bus should allow fast access to the screen. It's good that MCUs are getting cheaper too, but it's still more complex on the software side.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 30, 2015, 05:18:51 pm
content: Quote from: donotdespisethesnake on January 30, 2015, 05:02:52 pmYeah, I kinda wasted the last two days to investigate and would be surprised if I overlooked something.Quote from: donotdespisethesnake on January 30, 2015, 05:02:52 pmYes, saw them, but they are extremely rare and quite expensive. Don't want to be dependent one one supplier and for releasing something as Open Hardware, the parts should be easily to get over as longer period.Quote from: donotdespisethesnake on January 30, 2015, 05:02:52 pmYeah, I also have one 3.x touch" panel in my drawer I might use one day with a larger controller, but for smaller controllers, a low pin count is essential.

author: paulie
author_rank: Frequent Contributor
timestamp: January 30, 2015, 05:50:41 pm
content: Quote from: 0xdeadbeef on January 30, 2015, 04:04:22 pmIn what universe? Unlike the generic transreflective type those have zero visibility without backlight and even then half the readable range. So essentially require 100x more power and not useable outdoors. The yellow/green with trickle BL current can be seen in all conditions, direct sun to pitch black.

author: 0xdeadbeef
author_rank: Super Contributor
timestamp: January 30, 2015, 06:23:23 pm
content: Well, what sense does it make to discuss "white on blue" LCD without a backlight? Anyway, don't want to discuss the contrast of 1602 types anyway as I want something better.

author: wraper
author_rank: Unknown
timestamp: January 30, 2015, 09:06:19 pm
content: Take a look at ST7565/ SPLC501 based (and compatible) displays. Will need small SMT connector on the PCB though.

author: dgtl
author_rank: Regular Contributor
timestamp: January 30, 2015, 09:53:23 pm
content: Why not graphical displays? The STN type displays cost less than TFTs and offer much more flexibility than the text-mode displays. They are produced on a huge variety of sizes, colors and aspect ratios, so you can choose the best fit for your project. The connectors tend to be quite small though and you'll need adapter boards for most of them if you are not making PCBs. For some larger connectors (1.27mm pitch) you can solder on a ribbon cable with 2-row 2.54mm connector on the other side.Of course you need some kind of font rendering software on your microcontroller side. Some vendors provide their libraries; there are some opensource offerings as well. (I write my own).I have ordered some from here, so far no problems:http://www.buydisplay.com/default/graphic-display. They sell the connectors with the displays, so one less problem of finding a matching connector. You just need something to solder the connector to.

author: matkar
author_rank: Regular Contributor
timestamp: January 30, 2015, 10:13:44 pm
content: I've recently bought LCD ERC19264FS-1 at Buydisplay. It has a flat foil cable with a 0,5mm pitch.I made a few breakout boards for 36 (or less) way FFC connectors with JST PH backlight connector which facilitates interfacing the LCD.Driving the LCD is very easy with the help of provided source code as well.