Alpha smart neo 2 lcd screen - Page 1
Forum section: electronics / beginners

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 01, 2013, 06:36:28 pm
content: I got an alpha smart neo 2 which i naturaly took apartI found a nice large LCD screen which i would like to use but i am unable to find any datasheets or even how it communicates in order to display the characters.On the back it says that its made by data image (had a look and could not find it)PB266500P327REV:DOn the other side is:E154554SH-A94V-0Does anyone know how i could interface this with a micro such as an arduino?

author: amyk
author_rank: Super Contributor
timestamp: June 02, 2013, 08:10:45 am
content: If you still have what it connects to, you could reverse-engineer the controller interface - Mike has agreat videoabout that. Otherwise, you could try asking DataImage.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 08:50:30 am
content: I havesent an email over to data image but i shall have to see of i have te connecting board somewhere

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 04:40:40 pm
content: Ok ive had a look at the main micro controler (MC68VZ328AG) and it can comunicate via SPI or UART i dont know how it comunicates with the lcd but would it more likely be the uart?

author: mariush
author_rank: Super Contributor
timestamp: June 02, 2013, 05:03:16 pm
content: It's more likely SPI, if it's one of the two buses.But it could very well be 4-bit or 8-bit parallel, and have 2 or more display controllers on the back of the lcd, each taking care of a segment of the screen.This is very common for 4x40 character displays for example, there are two displays drivers on the back each doing 4x20 characters and you send data through a 4-bit or 8-bit bus with an additional pin through which you select which display driver gets what you send ( low/0 = driver 1, left side of screen , high/1 = driver 2, right side of screen)The microcontroller has 76 io's so it can very well do 4-8 x 4-8-pin parallel or something like that.How about you post some pictures of the insides, from google images i can only see the outsides. as clear as possible.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 05:05:33 pm
content: Yea sure, i litwraly had a look behind the lcd and all i can see is capacitors and resistors :/

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 05:14:36 pm
content: I belive there is some form of ic or controller on the ribbon cable at the top of the photo. Its one of the ones with the black resin over the top of it like in calculators.I belive its the same under the other black tape. I also noticed on both large rebbon cables that go to the screen it has: ST7565ST04 written on it. The first picture has the no 1 next to the ribbon and this one has the no 2 writen next to the ribbon.The frontThe main board where the lcd connects and the main contolerThere you goif you need anything else just ask, im going to be searching for some orm of data sheet for the microcontroler

author: mariush
author_rank: Super Contributor
timestamp: June 02, 2013, 05:41:36 pm
content: SiTronics ST7565 or something similar, and on the back of that lcd or under that epoxy there's probably two of these controllers in master-slave configuration.SiTronics ST7565 :http://www.lcd-module.de/eng/pdf/zubehoer/st7565r.pdfThis one is a 65x132 dot matrix... if you have more dots on screen you probably have 2 or for such drivers under the epoxy or on the back side of the pcb.Look at the flex strip on the lcd screen, those are the only wires that interest you.Either way, check datasheet and you get the connector pinout or how it's supposed to be.Then you can use a multimeter to see what wire from that connector sends 3.3v or 5v (or whatever input voltage is used) , and which wire sends the contrast for lcd (if it's not the same voltage and contrast is set on the back of lcd screen by resistors)once you know on which side the voltage is, the rest of the pinout should be like in the datasheet of the lcd driver, manufacturers don't usually mix up the pinout.See page 18 in datasheet... mpu interface is used on that connector ... the pins should be in that order, with maybe voltage, ground, backlight voltage on one side.NewHaven Displays use this ST7675 microcontroller in some of their graphical displays, for example for some 128x64 and 128x65 pixel screens :http://www.newhavendisplay.com/lcd-chiponglass-128-x-64-c-3_114.htmlhttp://www.newhavendisplay.com/lcd-chiponglass-128-x-65-c-3_115.htmlCheck the datasheets and the pinout of the connectors, maybe they match or help you reverse engineer it faster. The datasheets are attached at each lcd screen and you see what each screen uses under the product details.Here's one for example:http://www.newhavendisplay.com/specs/NHD-C12864B2Z-RN-FBW.pdfNote though that the newhaven ones are chip on glass so they really couldn't solder capacitors on the glass so their flat cable has more wires which are only there so you put capacitors on the end as you can see if you check datasheet. Those wires are probably not in your connector because the capacitors are on the pcb in your case already. So just jump over those pins when comparing datasheets.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 05:52:29 pm
content: I have found which pin is groundand i belive i know which one is the +5 / +3.3Both ribon cables have the black controler on there but i am unable to see the underside of the board, i am currently probing the vias with my multimeter to get a rough idea where there going.A couple of the pins on the white ribbon cable are not used, the most right one is ground then there are 2 not connecte pins, the next one alone is the + voltage supply i belive as it splits to goto ine ribbon cable and the other split follows the ground to the other ribbon cable, im still probing it though. Several pins on both ribbons are connected together so those could be the spi bus. I shall map it out now.

author: mariush
author_rank: Super Contributor
timestamp: June 02, 2013, 05:53:08 pm
content: And if that screen is more than 135px wide, see the datasheet of this 240x64 px screen Newhaven sells :http://www.newhavendisplay.com/nhdc24064woatfh3v3nonstocked-100pc-moq-p-1246.htmlThis uses 2 st7575s chips and you can see in picture there are two cables coming out but that's only because it's chip on glass so they didn't have pcb on the back to play with the wiring.Your screen may be like this but have some wires merged together to get a single connector with less wires ( so en, rs, rw , d1 to d8, voltage, ground, contrast etc shared while chip select and something else separate wires)It's unlikely it's SPI man, most likely it's just 4 or 8 wire parallel bus. The st7565 has an input which allows people to switch between 4pin or 8 pin parallel and serial input (2 wire, data and clock) but it just looks like too many wires in that connector to have serial data.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 06:12:21 pm
content: This is the connections that i have testedThe white connector pinouts are 1-16 whoch are right to left respectivly and the two robon cables are 1-43 left to right respectivly on the pictures.White ribbon - screen ribbon 1 - screen ribbon 21 - gnd - gnd2 - +3.3 - +3.33 - 5 - NC4 - NC - 55 - 8 - 86 - 18 - 187 - 17 - 178 - 16 - 169 - 15 - 1510 - 14 - 1411 - 13 - 1312 - 12 - 1213 - 11 - 1114 - 9 - 915 - 10 - 1016 - 7 - 7Pins 1 and 2 are ground an power.I belive that pins 2 and 3 are some form of chip selectAnd the remaining 12 pins are the data for parralel (8 i belive acording to datasheet) and maby contrast settingsWhat do you think?

author: mariush
author_rank: Super Contributor
timestamp: June 02, 2013, 06:21:45 pm
content: It's possible.There's 8 data pins and 3 other important pins which usually are after the 8 data pinsfrom newhaven datasheet with this chip datasheet:15~22 DB7~DB0 MPU This is an 8?bit?directional data bus.23 /RD MPU Active low Read signal24 /WR MPU Active low Write signal25 A0 MPU Register Select. 0: instruction; 1: data registerDoesn't mean they're in the same order on your display but they could be.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 02, 2013, 06:29:55 pm
content: I have had a close look and the ribbons do not start at pin 1 on the chip on the ribon, it starts off offseted so that pinout could be correct. How would i be able to test it out? Keeping in mind i font have much testing equipment here

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 04, 2013, 06:56:07 pm
content: How would i go about testing it if its a parrallel interface?Could it be done with an arduino?

author: amyk
author_rank: Super Contributor
timestamp: June 05, 2013, 09:09:49 am
content: It probably is parallel, a serial interface would have far fewer signals on the ribbon cable.All you need to do now is trace the pins to the pads on the chip - a microscope will be very useful for this as the pads aretiny.

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 05, 2013, 01:41:46 pm
content: i dont have a microscope :/i have a basic lab on from my basic paying jobi have a whole list of stuff i wana get but i cannotim gona route around to see if i can find a magnifying glass or something :/

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 15, 2013, 08:48:14 am
content: Ok i have been able to have a close look at the traces and i belive that that pinnout could be correct...What library should i use to give it a test on my arduino and because its a 3.3V screen could i use a potential dividor to drop the 5v signal to 3.3v as the informaion will only be traveling one way i belive