Looking for LCD Datasheet: Varitronix IZT2285-11 - Page 1
Forum section: electronics / projects

author: jonas.koeritz
author_rank: Newbie
timestamp: October 17, 2019, 11:20:31 am
content: Hi Everyone,This is my first post on here. I am currently working on the modernization of a Car Head-Unit and would like to keep the original display. I figured out most of the front panel but haven't found any information on the display.It has been manufactured byVaritronixin 2011 and it's a dot matrix display module with backlight. The part number isIZT2285-11. Connection to the front panel is done via a 20 pin, two row header. The front panel itself doesn't have too many connections left (5 or 6) for driving the display and does not contain any glue-logic or other circuits, so I assume this is some kind of serial bus like SPI.If needed I could also provide pictures of the display module.I really hope somebody can point me in the right direction.Jonas

author: amyk
author_rank: Super Contributor
timestamp: October 17, 2019, 11:42:00 am
content: Yes, pictures would be very helpful.Varitronix is still around, have you tried asking?

author: jonas.koeritz
author_rank: Newbie
timestamp: October 17, 2019, 11:45:44 am
content: Thanks for you answer,I haven't tried asking yet, thats a good idea...I've attached a picture of the modules backside.

author: mariush
author_rank: Super Contributor
timestamp: October 17, 2019, 11:51:48 am
content: Can you post some pictures, as clear as possible, especially area around connector?It could be something simple as the classic 8bit parallel connection : Voltage, Ground, lcd contrast, RS, RW, EN, Data 0 ..8 , Backlight Anode and Cathode (maybe 3 pins, for RGB backlight), maybe 1-2 pins for select chip (maybe 2 controllers are used, one for each half of the display, setting one pin high enables a particular chip)Here's an example of lcd display with two controllers on it and pins to select active controller :NHD-12864WG-BTFH-V#N, and here's datasheet for it:http://www.newhavendisplay.com/specs/NHD-12864WG-BTFH-VN.pdfSeeing the actual header and how the traces are going on the circuit board may help determine things.

author: jonas.koeritz
author_rank: Newbie
timestamp: October 17, 2019, 12:00:33 pm
content: I've attached an additional picture of the backside of the PCB the display has been mounted on. It's just passing some of the connections to the main PCB through it's board to board interconnect (I assume it's 5 traces only).The board to board connector has 20 Pins, of which I can only account the last 6 to display communication.The thicker traces looping around the top should be power for the display unit and backlight. The display is a monochrome dot matrix display with a single color backlight.The low number of actual connections to the main PCB made me think this might be some kind of SPI interface. The display is able to show arbitrary graphics (not HD44780 style custom characters only) and at least two different font sizes at once.I will receive a simple logic analyzer in the mail today so I should be able to probe some communication while the display is driven by the original PCB.

author: jonas.koeritz
author_rank: Newbie
timestamp: October 19, 2019, 10:16:44 pm
content: In the meantime I took my newly arrived logic analyzer to this device and can say it is definitely using 4 wire serial communication/SPI. I read a lot of datasheets, hoping to find a similar device and started reverse engineering the protocol.I observed that my display seems to require commands followed by parameters, like a set segment command followed by a segment number. Most of the controllers I read the datasheets for do this in a single command, containing the segment number in the lower bits of the command. Is anybody aware of a controller that's working like that or similar?