Dot matrix display help

[Ronnie Dent]

Probably a long shot but this DMD is from my recently bought pusher, it just scrolls number and letters so it does work, but has lost it's flash memory, it has an 8bit controller chip which must have had the code, just wondered if anyone on here could maybe do something with it? it's a shame as it looks neat with red and green text. Just not sure exactly what messages it should show?

Thanks Ronnie

 

[obcd]

Shouldn't it receive it's text from another device?

Maybe at powerup, the ram contains random characters and that's what it's displaying.

It would suprise me that they programmed a fixed text in that controller. If that would have been the case, if the flash would have been erased, the program code would likely be gone as well.

The microcontroller might have a section of eeprom memory that they could use to store the text. That memory usually can be read and written separatly from the microcontroller it's flash memory.

P1 looks like it was designed for a DB9 with pin 2, 3 and 5 connected. Maybe the small chip on the right of it with the 4 capacitors is a max 232 or other level converter which would make sense for a rs232 interface.
obcd2016-06-19 23:38:33

 

[Ronnie Dent]

Thank you for the reply, the only thing that connects to the display is the power plug which has 2 ground wires and a +5v and +12, it does have a rs232 socket on the other side but no cable or even a socket for one on the motherboard, it has a very tiny computer motherboard. It does when first powered on display clearly the manufacturer "KEAON" but then goes on to scroll 0 1 2 3 4 5 A B C D and son on, I could have a look at that chip next to P1 if it would help.

Thanks Ronnie

 

[obcd]

It looks like you have smaller J6 connector between that DB 9 (not mounted) and the chip on the right of it. It seems to have the same TXD RXD and GND signals that you need for a serial interface. Maybe that one was used for the connection between the display and it's driving source? (Second picture) Maybe it would help if you could give brand and model of the pusher it came from.

 

[Ronnie Dent]

It looks like you have smaller J6 connector between that DB 9 (not mounted) and the chip on the right of it. It seems to have the same TXD RXD and GND signals that you need for a serial interface. Maybe that one was used for the connection between the display and it's driving source? (Second picture) Maybe it would help if you could give brand and model of the pusher it came from.

All the plugs you see in the pics have sockets fitted but are covered by the metal fixing plate so could not have been used apart from P1 which has a cut out. The machine is made by Keaon and is called Kash Kong, the other model was called Frooty Looty. could find very little info via google, have attached a pic of the machine, could also take pics of the main boards if it would help? I also managed to get a scan of the manual but it has no mention of the dot matrix! thanks again for you help.

Cheers Ronnie

 

[Muppz]

According to the spec sheet it has no separate data storage it does have an additional boot 4K Rom though.

I do see a socketed 8pin chip at the bottom of the board, I dont suppose that is an I2C eeprom or Flash is it?

 

[Ronnie Dent]

According to the spec sheet it has no separate data storage it does have an additional boot 4K Rom though.

I do see a socketed 8pin chip at the bottom of the board, I dont suppose that is an I2C eeprom or Flash is it?

Thanks for the reply, which spec sheet are you looking at? I can easily remove the display and check that 8 pin IC for markings.

Cheers Ronnie

 

[Muppz]

spec sheet for the controller

www.keil.com/dd/docs/datashts/winbond/w78e58b.pdf

Sorry can't figure out how to make it clicky

edit: ah it made it clicky anyway

Muppz2016-06-20 14:52:45

 

[Ronnie Dent]

Ah I see, I thought you meant machine data sheet lol

 

[Ronnie Dent]

From what I have found out this fault with the DMD is common and most now do what mine is doing!

 

[Ronnie Dent]

I have been emailing UDC in the uk who were the distributors for these machines asking about stuff and they also scanned the manual for me which was great, but it contains no tech stuff at all, but here was the response for the dot matrix-

dot matrix unfortunately we cannot reprogram them any more we have some left but

only with 10p scrolling massage or other ones with just scrolling alphabet letters and

numbers .

 

[philmurr]

Looks like the W78E58B microcontroller ROM contents has been lost / corrupted which I guess means the thing is useless

If you can get the actual code (maybe from UDC?) I can programme the chip for you, unfortunately the code can be read-protected so even if you can find a working display it's unlikely you can pull the code out of it.

 

[Ronnie Dent]

Looks like the W78E58B microcontroller ROM contents has been lost / corrupted which I guess means the thing is useless

If you can get the actual code (maybe from UDC?) I can programme the chip for you, unfortunately the code can be read-protected so even if you can find a working display it's unlikely you can pull the code out of it.

Thanks Phil, I can ask the question but it seems they work on swap things until it works so doubt they will have the code

Thanks Ronnie

 

[obcd]

If the rom contents would have been lost, it wouldn't show any activity at all. (Besides perhaps random pixels lighting up.) Have you checked that small chip in the socket? It could be a I2C eeprom or an fram that stores the messages. Could you just check the number written on that chip? As the thing has a serial interface, there was a way to load custom messages. I doubt they hardcoded the messages in the microcontroller firmware. Nowadays, it's common that those controllers have buildin eeproms, but when the display was designed, they might have used a separate chip. The scrolling letters and numbers could be a sort of display test with an unprogrammed message, or could be the eeprom that stored it's memory adresses into it's memory cells. Besides the numbers and letters, do you see any other ascii characters on the display?

If the display is using a separate eeprom or fram chip, it might be possible to analyse the contents of one and recreate some usefull text by program another one using an external eeprom programmer. The text will probably be plain ascii, but they might use some special control codes to choose the color of the display, make a text blink on it or make it scroll in vertically instead of horizontally. It depends upon the options the display was having. If you are unlucky, there could be a checksum or crc on the contents of the chip.

 

[Ronnie Dent]

Hi obcd, thanks again for the reply, it does display strings of other characters like a test pattern £ $ ( ) & etc.. I will remove it and check that small chip and report back tomorrow

Thanks Ronnie

 

[Ronnie Dent]

Right the small 8 legged IC is marked Atmel 42693C46 P127

And the IC beside the p1 port is HIN232CP hope that helps in some way.

Thanks Ronnie

 

[Ronnie Dent]

It looks like it is an Eeprom http://www.atmel.com/Images/doc5140.pdf

I have a G540 programmer but doubt it's any use for that? also have a logic probe and a scope, fairly good with the probe but scope not so...

 

[obcd]

Indeed, the 93C46 is an eeprom. It looks like it's using an SPI interface altough they don't mention it in the datasheets. (I have just read them fast so maybe I missed it.)

If your programmer can't handle those, you might be able to build one using a cheap arduino board. Obviously, you will need to do some programming for that. I have done something similar to read the eeprom of an xbox, but that's using the IIC protocol. I could mail you the code so it can serve as a framework.

It might also help if they could sell you a chip from a board showing the 5ct message. At least that still contains it's normal contents I assume. Maybe they could simply mail you a hexdump of it's contents as it's only a 128 byte device. It all depends how service "client oriented" minded they are. Most firms won't try to help you, unless you consider buying 10 new machines from them.

You could say it might help them in fixing their own displays, but most are to proud to see a benefit in that. If you don't ask, you will never know.

 

[philmurr]

The 96C46 93C46 is listed as being compatible with the G540 so give it a try and see what you can read out of it

Edited: typo

philmurr2016-06-22 13:08:45

 

[Ronnie Dent]

Thanks guys for the replies, I would need to make the chip fit the G540 somehow but will have a look.

I have asked UDC if they have the rom image, they seem very helpful but not sure how involved the tech department might be, most just do board swaps until things work!

Thanks Ronnie