Optrex 323 1867 display - Page 1
Forum section: electronics / projects

author: symbianas
author_rank: Regular Contributor
timestamp: December 23, 2019, 10:28:05 pm
content: Hi, I would like to try to play with Optrex 323 1867 (rebranded as KYDE 3232351) monochrome display (256x26 pixels).I did not find any documentation about it. The only thing I found is Optrex 323 display:http://serdisplib.sourceforge.net/ser/optrex323.htmlAs I understand it contains of 2 displays, each has 34pins and contains 128x26 pixels. For start I would like to control one of them. I have the board from which display was taken. It has single 32pin connector to which all display and button data flow go.I have analyzed the board and identified which pins go through that connector:Display pins -> (board connector) MeaningCode:2 -> (30) GND3 -> (30) GND/Power +5V (One display goes to GND another to Power on this pin)16 -> (30) GND17 -> (26) Power +5V (with resistor 100 ohm)18 -> ( 7) D0?19 -> ( 8) D1?20 -> ( 9) D2?21 -> (10) D3?22 -> (11) D4?23 -> (12) D5?24 -> (13) D6?25 -> (14) D7?26 -> (32) ? (with resistor 0 ohm)27 -> (19) ? (with resistor 100 ohm)28 -> ( 5) ? (with resistor 100 ohm)29 -> ( 6) ? (with resistor 100 ohm)30 -> (21) ? (with resistor 100 ohm)How could I identify these pins with "?" ? And how could I connect all these pins to Arduino?

author: symbianas
author_rank: Regular Contributor
timestamp: December 26, 2019, 06:15:27 pm
content: So I did further investigations. This display contains of 2 256x13 pixel displays.Display pins -> Meaning (where goes on original board)2 -> GND3 -> GND/Power (one display goes to GND another to Power on this pin)16 -> GND17 -> Power18 -> D0? (on original board goes toMC74VHC541 Bus Buffer chippinY8)19 -> D1? (on original board goes toMC74VHC541 Bus Buffer chippinY7)20 -> D2? (on original board goes toMC74VHC541 Bus Buffer chippinY6)21 -> D3? (on original board goes toMC74VHC541 Bus Buffer chippinY5)22 -> D4? (on original board goes toMC74VHC541 Bus Buffer chippinY4)23 -> D5? (on original board goes toMC74VHC541 Bus Buffer chippinY3)24 -> D6? (on original board goes toMC74VHC541 Bus Buffer chippinY2)25 -> D7? (on original board goes toMC74VHC541 Bus Buffer chippinY1)26 -> ? (on original board goes toMC74VHC541 Bus Buffer chippinOE1)27 -> ? (on original board goes toH8S/2674R microcomputerpin 89PF4/HWR)28 -> ? (on original board goes toH8S/2674R microcomputerpin 6PC0/A0)29 -> ? (on original board goes toH8S/2674R microcomputerpin 86PF1/UCAS/IRQ14)30 -> PowerWhat does MC74VHC541OE1 pin OE1 do? Also what do H8S/2674R pins PF4/HWR, PC0/A0, PF1/UCAS/IRQ14 do?Any help on driving this display with arduino?

author: symbianas
author_rank: Regular Contributor
timestamp: December 27, 2019, 09:42:46 pm
content: Any help how to guess drivers and pins? What other investigations I could do which would help?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: December 28, 2019, 02:15:26 am
content: If you want to go the reverse-engineering route, you should whip out a scope and check out those 4 signals you don't know about. One of them will be a clock signal, most likely.Does this product that you got the display from still work? It would be interesting to swap pin 3 of the two displays to see what happens. Perhaps this is how they self-identify?To figure out more and drive it yourself, you will probably need to see it in action so that you can learn the interface through reverse-engineering rather than looking at datasheets.PF4 is general purpose IO but can be configured as:"Strobe signal indicating that external address space is to be written, and the upper half (D15 to D8) of the data bus is enabled.Write enable signal for DRAM interface space."PC0 is probably being used as GPIO here. Its special function use as A0 would make more sense if the rest of the port was also connected to the display.Alternatively, the display may be connected to the MCU as if it's a DRAM like the diagram shows on page 235 of the datasheet.

author: symbianas
author_rank: Regular Contributor
timestamp: December 28, 2019, 04:19:20 pm
content: Quote from: Prehistoricman on December 28, 2019, 02:15:26 amThanks for reply man.Yes, original device is still working with this display and I can do measurements. However swapping pins is complicated as they are tiny 0.5mm size. I have ordered FPC connector to make pins bigger and might be able to swap them latter.I am able to change contrast from original device, but I don't observe any voltage drop in any of the power or other pins. Does this mean that contrast could be sent as a command not as a separate pin input?As I don't have oscilloscope (I am considering to get it if it would help), I used simple voltage tester, while display was powered in original device:PC0/A0 =0 - 0.01V(fluctuates from - to)PF1/UCAS/IRQ14 =3.27V(seems to be same as display power)PF4/HWR =3.26 - 3.27V(fluctuates from - to)OE1 =0.71 - 0.74V(fluctuates from - to)

author: symbianas
author_rank: Regular Contributor
timestamp: December 28, 2019, 06:22:24 pm
content: Also I have over viewed these display drivers:KS0108- seems to be 5V power and does not have contrast command.S1D15705- possible to power 3.3V and has contrast command, also can drive second slave display -possible candidate?S6B0724- possible to power 3.3V and has contrast command, also can drive second slave display -possible candidate?sed1335- seems to be 3.5V-5V? power and does not have contrast command, also can drive second slave display.SED1520- seems to be 5V? power and does not have contrast command. Can drive second slave display though.SED1530- seems to be 3.3 (SED1531) -5V? and has contrast command, also can drive second slave display -possible candidate?(Optrex 323 display also uses this)Any other I should look into? Any other thoughts?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: December 28, 2019, 09:36:21 pm
content: Quote from: symbianas on December 28, 2019, 04:19:20 pmAh that's useful knowledge about the contrast.Looks from those voltages that OE1 would be the clock. The meter is averaging out the waveform to 0.7V so the duty cycle would be about 22%. Does your multimeter have a frequency mode?If this is a memory interface, there is no reason for the MCU to read from the display's memory, so the write enable would be on all the time. Perhaps that is PC0?However, bear in mind that the display may not be constantly accessed by the MCU. Probe the data pins to see if anything is happening. If the display is fairly static, that could explain why there's not much going on with your PF1 and PF4 pins.I've looked at a couple of those display drivers you found and they seem to have a few more pins than you've found in this one. I wouldn't be surprised if this is a completely new driver.In that case, you would want something more like a logic analyser to see the instructions/data that are being sent to the display.

author: symbianas
author_rank: Regular Contributor
timestamp: December 29, 2019, 12:30:35 am
content: Quote from: Prehistoricman on December 28, 2019, 09:36:21 pmSadly my multimeter is too simple and does not have frequency mode. I made another DC Voltmeter with Arduino. This is what happens on OE1:Not sure if these readings helpful and accurate enough: AVG ~0.7V; MAX ~2.2V; clock?Quote from: Prehistoricman on December 28, 2019, 09:36:21 pmYes, display was static when I took measurements, here are some measurements when display active:PC0/A0PF1/UCAS/IRQ14PF4/HWR seems to be similar to PF1/UCAS/IRQ14OE1How does "MC74VHC541 Bus Buffer" chip work? I don't understand why buttons connected on A1-A8 pins; display on Y1-Y8/OE1 pins; MCU on OE2 pin?Also just to mention, I think this display has controller "Chip-On-Glass" as it has black dots/chips on cable.Quote from: Prehistoricman on December 28, 2019, 09:36:21 pmSomething like this?USB-Logic-Analyzer-Device-Set-Compatible-to-Saleae-24MHz-8CH-for-ARM-FPGA-M100This would be better than oscilloscope?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: December 29, 2019, 05:28:59 pm
content: Quote from: symbianas on December 29, 2019, 12:30:35 amI would strongly recommend getting something a step above the super basic meters. Do you, by any chance, have a yellow one with manual ranges and a transistor tester?I have a few meters, but the cheapest is an Aneng AN8002 that has a lot of features for its very low price. You get frequency, duty cycle, capacitance, temperature, millivolts ranges (in addition to the normal ones) which are super useful.If you want a microamps range (which the AN8002 lacks), you can get one of their slightly more expensive models.Your trace from the Arduino is undersampled, which means you aren't getting enough samples per second to see the nature of the signal. You can attempt to use the Arduino as a logic analyser, but it has low memory.Quote from: symbianas on December 29, 2019, 12:30:35 amThe buffer exists to allow the MCU to access multiple parallel-bus devices while having all of those devices on the same bus. If you trace back the connections to those buttons, they will most likely go back to the MCU.If not, then something very unusual is going on.Quote from: symbianas on December 29, 2019, 12:30:35 amThat is the kind of thing I was talking about. I don't have any recommendations for logic analysers because I don't have one.You will want something more like 12 channels for this project since you have that many lines to probe.Most bench oscilloscopes won't have enough channels to do logic analysis without the extra LA option that usually costs a lot.In summary: Scopes are great for viewing live data and analogue signals. LAs are great for capturing lots of channels of data over a small amount of time (and then you store to PC for manual analysis later).

author: symbianas
author_rank: Regular Contributor
timestamp: December 29, 2019, 06:17:58 pm
content: Quote from: Prehistoricman on December 29, 2019, 05:28:59 pmNot yellow, but yeah, with manual rangesMastech 830-bz. I guess I should step-up and get a better one, but maybe something with oscilloscope, for hobbyist?Quote from: Prehistoricman on December 29, 2019, 05:28:59 pmIndead, buttons and display data pins seems to be going not only to bus buffer chip but also to MCU.Quote from: Prehistoricman on December 29, 2019, 05:28:59 pmI did not find 12channel logic analyzer. I found 16channel which cost ~40$; 8channel logic analizer - ~6$. Should I still get 16channels?I hope I will be able to hack this display with it if not it will be ~40$ down the drain. But I guess I will be able to use it as USB oscilloscope later?What do you think about this:16MHz on 16channels:Kingst LA1010 USB Logic Analyzer 100M max sample rate16 Channels10B samples MCU ARM FPGA debug tool OscilloscopesOr better to pay a little bit more and get 2 in 1 (oscilloscope and logic analyzer)? but its 10Mhz on 16channels.Hantek 6022BL PC USB Oscilloscope 2 Digital Channels 20MHz Bandwidth 48MSa/s Sample Rate 16 Channels Logic AnalyzerWhich is a better choice?Also I wrote some code with Arduino to try to brute force commands to display, but it seems to be hopeless... I guess they must be in specific sequence and timing...

author: Prehistoricman
author_rank: Regular Contributor
timestamp: December 30, 2019, 02:32:06 am
content: Quote from: symbianas on December 29, 2019, 06:17:58 pmHandheld oscilloscopes are a bit of a gimmick in my opinion. Your choice.I recommend a better meter for a few reasons: features and safety mostly. Your meter is rock-bottom in terms of safety and price. Also I've had two of those kinds of meters and they both died mysteriously.Quote from: symbianas on December 29, 2019, 06:17:58 pmIt's also your choice on LA. You will get by with 8 channels (probably). But it's best, as I said, to stay away from the cheapest option with tools. If you're going to continue doing stuff in electronics, it's great to build up a collection of useful and dependable tools.Do you have any idea on the frequency of the signals on this board? You want to get something that has enough performance to do the job at hand.Also, be wary of these cheap Chinese options. They often advertise in misleading ways to make the product look better than it is. This is essentially an unregulated market so lots of crap comes in. For example, that Hantek you found is an obvious Picoscope ripoff that can't get its own specs right (it says both 10M and 20M bandwidth for the LA, also is this bandwidth or sample rate? You can't trust anything they say. And Windows XP screenshots).You can see the Kingst only has 16MS/s with all 16 channels. 32MS/s with 9 channels should be enough (at a guess) for what you're doing.Quote from: symbianas on December 29, 2019, 06:17:58 pmYou have a breakout to connect the display to the Arduino already?

author: symbianas
author_rank: Regular Contributor
timestamp: December 30, 2019, 08:41:23 am
content: Quote from: Prehistoricman on December 30, 2019, 02:32:06 amKingst only has 16MS/s with all 16 channels. 32MS/s with 9 channels.Hantek only has 10MHz with all 16 channels. 20Mhz for 2 channel oscilloscope. It does not write that you get more bandwidth if you use less channels.Not sure how much Mhz do I need?Kingst is a better choice here? Or you recommend something else entirely?Quote from: Prehistoricman on December 30, 2019, 02:32:06 amYes, it so happens that I have FPC connector and was able to connect wires easily to Arduino, so that made my life a lot easier:However I don't think brute force will work... Need to get LA

author: Prehistoricman
author_rank: Regular Contributor
timestamp: December 30, 2019, 11:37:27 am
content: Quote from: symbianas on December 30, 2019, 08:41:23 amMost likely the Hantek will have higher sample rate for less channels. But they don't say that, so I wouldn't buy it on the principle of good descriptions. If they can't be bothered to copy over the specs sheet, why should you encourage that by purchasing?Quote from: symbianas on December 30, 2019, 08:41:23 amLook around the board for clock crystals. The CPU can multiply its input clock by up to 4 and the resulting clock frequency has to be between 8 and 33MHz.However, I think the DRAM interface (if it's being used) can operate faster than then input clock.

author: symbianas
author_rank: Regular Contributor
timestamp: December 30, 2019, 09:53:15 pm
content: Quote from: Prehistoricman on December 30, 2019, 11:37:27 amOk, I will order the one without oscilloscope, I will need just to wait for a month or so... will update post, with any findings.Quote from: Prehistoricman on December 30, 2019, 11:37:27 amOn board I see few writings: 8.0Mhz/11.2Mhz/14.28Mhz/16.93Mhz. I think its 14.28Mhz because its closest to the MCU and seems to be connected PLLVcc pin. so it might be 57,12Mhz?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: December 31, 2019, 04:29:38 am
content: Could be up to 28.6MHz. I don't think this chip supports greater than 33MHz.

author: symbianas
author_rank: Regular Contributor
timestamp: March 11, 2020, 10:41:01 am
content: Quote from: Prehistoricman on December 31, 2019, 04:29:38 amSo finally I received all parts!My setup:First two wires reading:Is there any useful information from those 2 wires? Like, can I sample all 16 wires at 16Hz?I tried disconnecting one by one wire and turn off/on display (to try to skip "initialize" sequence and see which wires are needed for initialization sequence), but when I connect wire back (so display should show nothing as it was not initializes) display works as nothing happened, so I wonder how initialization sequence works?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 11, 2020, 01:49:47 pm
content: Quote from: symbianas on March 11, 2020, 10:41:01 amThat's great.What are these small pulses on channel 1? I'm wondering if they're spurious.Are these 3.3V logic? You should change the logic threshold if so. I can't tell by your original post where you said Vcc was 5V, but later on implied 3.3V.Are these two signals really the only ones of interest? What about that bus buffer chip?Quote from: symbianas on March 11, 2020, 10:41:01 amThat's an amazing idea! There is a chance that these displays are doing smarter communication with the host processor and it knows they aren't initialised. Have you tried to capture what happens as you connect the signals?

author: symbianas
author_rank: Regular Contributor
timestamp: March 11, 2020, 04:24:29 pm
content: Those pulses should be valid. I just connected them to two "D7?"-"D6?" pins. (D pins are going to buffer chip)Code:Display pins -> Meaning (where goes on original board connector and meaning)5 -> (22; 23) (different for each display)6 -> (7)7 -> (9)8 -> (21)9 -> (8)10 -> (19) D0?11 -> (18) D1?12 -> (17) D2?13 -> (16) D3?14 -> (14) D4?15 -> (13) D5?16 -> (12) D6?17 -> (11) D7?18 -> POWER19 -> GND32 -> GND; POWER (different for each display)33 -> GNDAt first I assumed it is 5V as I saw 5V in some places written on the board. When I measured pins with multi-meter of display it seems to be 3.27V. But It seems that logic analyzer captured values even with 5V set up? I set it to 3.3V CMOS now.Quote from: Prehistoricman on March 11, 2020, 01:49:47 pmWell I was wondering what if you initialize the display and after that disconnect and connect it again? host processor should think its initialized, but display should not show anything. But maybe thats not how it is. I noticed there is some data flowing when connecting this radio to the power. So maybe display is initialized once radio unit gets power and not when on/off button is pressed.All D pins here:I wonder what is that space between numbers. Does this mean its 32MHz is not enough for 9channels?

author: symbianas
author_rank: Regular Contributor
timestamp: March 11, 2020, 04:40:00 pm
content: When display is in "Test mode" menu and displays grid:

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 11, 2020, 09:48:36 pm
content: What happens if you disconnect various data lines?Can you zoom in a bit on one of the bursts you found in the last image? Maybe record the other 2 lines as well to see if they're related to these data lines.

author: symbianas
author_rank: Regular Contributor
timestamp: March 12, 2020, 09:21:23 am
content: If I disconnect any of display wires, display starts flickering, or display nothing. I have connected all 14wires which goes to display, it inclueds power wire. So in total 13 wires + power (channel9) + ground.Power (channel9) always on.Zoomed out:Zoomed in:

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 12, 2020, 09:41:53 am
content: Okay that looks nice. I'll just say everything I'm thinking of.0x55 and 0xAA is GREAT. You're running the test pattern yes? 55 = 01010101 and AA = 10101010. Since these two values don't logically come after one another, perhaps they are controlling vertically adjacent lines. BE, 6D could be some command, address, or something else.You should set the parallel analyser to record results on an edge of the signals at the bottom (whichever edge looks best) and then you will get a nice list of all values sent.zoomed 3 is super interesting. You can see how the signals at the bottom change wire. The short pulses change from 10 to 8, and the longer ones stop being on 13.I'm thinking these are chip select or clock lines.I'm wondering why the data is unstable while it's changing. Are you measuring after the bus buffer? If so, I guess they are just leaving the output enable on and not caring about unclocked states. But this also shows that maybe they aren't using a whole port on the microcontroller to output every bit (which is odd).Edit:Try to swap channel 8 and 10 and see if the displays are swapped too. Obviously it will be best not to run the test pattern in this case.

author: symbianas
author_rank: Regular Contributor
timestamp: March 12, 2020, 03:18:40 pm
content: I have switched Channel11 with Channel12 and indeed display switched places:If Chennels 0-7 is data, what are channels 8;10;13?Code:Display pins -> Meaning (where goes on original board connector and meaning)5 -> (22; 23) (different for each display) (Channel11 and Channel12)6 -> (7) (Channel9)7 -> (9) (Channel13)8 -> (21) (Channel10)9 -> (8) (Channel8)10 -> (19) D0? (Channel7)11 -> (18) D1? (Channel6)12 -> (17) D2? (Channel5)13 -> (16) D3? (Channel4)14 -> (14) D4? (Channel3)15 -> (13) D5? (Channel2)16 -> (12) D6? (Channel1)17 -> (11) D7? (Channel0)18 -> POWER19 -> GND32 -> GND; POWER (different for each display)33 -> GND

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 12, 2020, 10:38:19 pm
content: Quote from: symbianas on March 12, 2020, 03:18:40 pmI would speculate they are chip selects or clocks. However, if they were chip selects I would expect them to last much longer. And if they are clocks, there's so many that they're redundant.I see two more images now. Did you know you don't have to use an image sharing website? We have good image support on the forum. Speaking of that, I've attached some thoughts scribbed on your zoomed 5Can you answer my questions and points from the last message?At this point, I would do one of two things:Capture the data and try to play it back with an Arduino or something. Then experiment.Capture the data and make a script to attempt to visualise it. That way, you can see lots of things like pixel polarity, the exact format of the data, etc. just by trial.

author: symbianas
author_rank: Regular Contributor
timestamp: March 13, 2020, 04:48:00 pm
content: I think display usesSED1530drivers.Channel_8 = RD (HIGH/LOW)Channel_9 = POWER (another power?)Channel10 = A0 (HIGH/LOW)Channel11 = Display1 selected (HIGH/LOW)Channel12 = Display2 selected (HIGH/LOW)Channel13 = WR (HIGH/LOW)It seems that D0-D7 is inverted, If I change them I get different hex values which matches SED1530 commands:0x2F - Set Power Control0x81 - Set Electronic Control0x1_ - Set Column Address0xA6 - Normal/Reverse Display0xA4 - Entire Display ON/OFF0xAC - Set Standby0x7D - Initial Display Line0xB_ - Set Page AddressThough I find some missing commands (maybe they are inconsistences? or its wrong guess...):0x26?0xE3?

author: symbianas
author_rank: Regular Contributor
timestamp: March 15, 2020, 05:41:19 pm
content: So its SPLC501C driver which seems to be almost the same as SED1530, but has few additional commands. I was able to display stuff on display by trying to write same commands as I read.Attached result.Now I need to try read pins that radio sends to display and re-translate them to display. After that I could modify re-translation and intercept what is being displayed. Not sure if that is possible.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 15, 2020, 08:01:34 pm
content: Awesome! I'm impressed you found the exact driver that they're using. How did you do that?So the goal is to make translate the default commands to drive another display?

author: symbianas
author_rank: Regular Contributor
timestamp: March 16, 2020, 10:00:48 am
content: Quote from: Prehistoricman on March 15, 2020, 08:01:34 pmWell, I have found information on Optrex 323 display which is different, but same manufacturer and it uses SED1531 driver. When I searched for SED1531 driver I got some suggestions about SED1530/SPLC501C as I understand they are the same or very similar, has few additional functions. And bingo, the codes I saw in logic analyzer matched the codes in documentation.Quote from: Prehistoricman on March 15, 2020, 08:01:34 pmFirst goal would be to intercept signal - to read data pins which are sent from radio with arduino/stm32 and write them to display. Then to try to add additional information on display since radio is connected to CAN BUS I can read a lot of useful information about car and display it.Second goal would be to use another display, but this step is challenging, as I would need same dimensions display or to 3D print radio front panel, but I have no experience with 3D printing...

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 16, 2020, 07:48:59 pm
content: What are the brains in this unit as it stands? I would poke about, see if there's a microcontroller with firmware that could be modified (but I'm crazy so most people would not do this).

author: symbianas
author_rank: Regular Contributor
timestamp: March 17, 2020, 03:20:49 pm
content: Quote from: Prehistoricman on March 16, 2020, 07:48:59 pmI think its Renesas H8S/2674R microcomputer which drives display. On board there is also ST10F273M chip and also S29AL016D70TF 16MB flash memory. I tried reading flash memory as I imagine all the software information is there, but has no luck, so decided to try to understand display itself. But still it would be hard to understand assembler code. I think coding with arduonu/stm32 should be much faster, but yes solution does not look very elegant.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 17, 2020, 11:00:37 pm
content: Well IDA Pro supports that architecture. You can find that software for free in the right places, as I have.If you don't know what IDA is, it basically makes the reverse-engineering process with assembly much easier.

author: symbianas
author_rank: Regular Contributor
timestamp: March 19, 2020, 06:01:03 am
content: Quote from: Prehistoricman on March 17, 2020, 11:00:37 pmAnd how would you read/write the data from/to Renesas H8S/2674R, ST10F273M, S29AL016D70TF?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 19, 2020, 11:18:07 am
content: One hopes that the program is stored in that flash chip. So you could dump it, analyse with IDA, make changes (probably with a hex editor), and overwrite the same flash.Flash datasheet:https://www.digchip.com/datasheets/parts/datasheet/013/S29AL016D70TF-pdf.phpCPU family programming manual:https://www.st.com/content/ccc/resource/technical/document/programming_manual/27/c0/48/83/94/9d/4d/45/CD00147146.pdf/files/CD00147146.pdf/jcr:content/translations/en.CD00147146.pdfIDA might not support the instruction set of that CPU but it does support the Hitachi H8S ISA, so one would assume that your Renesas CPU uses that.

author: symbianas
author_rank: Regular Contributor
timestamp: March 20, 2020, 07:56:00 pm
content: Quote from: Prehistoricman on March 19, 2020, 11:18:07 amWell thats hope. What device do I need to get to read/write it? I bet its not cheap.As for reading signals from radio with arduino/stm32 its too slow, I guess its impossible to read pins with software. for example WR takes 187nanoseconds when its LOW, so during that time I need to get all D pins and so on... Is there any hardware module which whould be cheap and would help to read and send signals to arduino/stm32?

author: Prehistoricman
author_rank: Regular Contributor
timestamp: March 20, 2020, 08:16:20 pm
content: You can read the bus using any old 8-bit latch, such as this one:http://www.ti.com/lit/ds/sccs075/sccs075.pdfNot that part in particular though because it uses 5V IO.I don't know what programmers would support that flash chip. It's probably not hard to make your own with an Arduino, but you will need more of those latch chips to expand the IO because this thing needs 35 address and data lines

author: bsehovac
author_rank: Newbie
timestamp: November 05, 2024, 09:57:56 pm
content: Hey man, have you ever figured this out? I want to use same display with Arduino in Mini Cooper R56 to make OBD2 reader since I have single din radio installed, and well the old radio is just sitting there unused... 😅 I stumbled upon this docs on waybackmachine, not sure could it be helpful?https://web.archive.org/web/20060328202659/http://www.optrex.com/pdf/Dmcman_full.pdfhttps://web.archive.org/web/20061026025306/http://www.optrex.com/SiteImages/PartList/SPEC/51851ade.pdf