I'm trying to make a dot matrix message board -type thing work,

The dot matrix IC's are the DL-57 Alpha Numeric Dot Matrix Display [Data Sheet] : https://drive.google.com/file/d/0B6Pibr6_2jwcQ2xmRUIwTjFBZ0k/edit?usp=sharing

Which is pretty simple as you can see, hwoever the hard part comes in where I want the message to be configurable, not on the fly though.

I know I need some kind of ROM, and the one I have right now is the M27C256B, it's a UV EPROM (Data sheet shown here : http://pdf.datasheetarchive.com/datasheetsmain/Datasheets-20/DSA-394559.pdf)

Erasing it is no problem, obviously, but programmers are mega expensive, I did google for some DIY programmers, but the only ones that I could find were in a google cache.

Is there any other way to make a sort-of-ROM-thing with other IC's? Or maybe I overlooked some DIY EPROM programmer?

Any help would be appreciated.

(I also have a UV EPLD : EP900 DC-3 3F19007 (datasheet available but I already have two links in here) , but again the problem is programming the thing....)

Any help would be welcomed, I do have a large stock room of TONS of parts, so please, if you have some kind of schematic for building a programmer, that would be much appreciated.


closed as unclear what you're asking by Chetan Bhargava, Matt Young, Daniel Grillo, Joe Hass, Dave Tweed Feb 19 '14 at 5:42

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  • \$\begingroup\$ A large enough MCU can be programmed to be a programmer, and using a 28XXX or 29XXX will let you get away with only using a 5V supply. \$\endgroup\$ – Ignacio Vazquez-Abrams Feb 17 '14 at 1:05
  • \$\begingroup\$ That datasheet is just for the display, not for any driver. You need drivers before you can even worry about displaying any message... They are 5x7 displays that need to be scanned/multiplexed. How many individual displays? \$\endgroup\$ – Passerby Feb 17 '14 at 1:28
  • \$\begingroup\$ Like many older EPROMs, the M27C256B requires a higher voltage (12V) in order to program it. This makes in inconvenient to build your own programmer. It is basically obsolete. \$\endgroup\$ – DoxyLover Feb 17 '14 at 2:50
  • \$\begingroup\$ I've tested them out individually, all they need is power and ground. No drivers. On and off for each LED. I have about 5 of these little guys. Yeah, I've decided to go with a microcontroller. \$\endgroup\$ – Tropical_Peach Feb 17 '14 at 3:30

Why do you need to use a ROM or EPROM/EEPROM? How are you planning on using that to drive these LEDs?

What you're trying to do is easy to accomplish with any microcontroller. You'll need to multiplex the LEDs (so you don't have to drive each individually) and connect at least one side of the LEDs (rows or columns) to a driver like the ULN2803. There is tons of information on the web about doing this.

A google search for "led matrix microcontroller" turns up: http://www.create.ucsb.edu/200C/2008_Students/MAT-200C_2008_Files/matt_stabile/MAT200CStabile.pdf



  • \$\begingroup\$ I wanted to use a ROM for one because I wanted to use only IC's. However, you do have a point in using a micro-controller, I have a few 'Dunios and PIC's I can program and then just use the IC off the board. Another reason I wanted to use a ROM is because I don't have any experience with them and wanted to get experience with them. \$\endgroup\$ – Tropical_Peach Feb 17 '14 at 1:14
  • \$\begingroup\$ A ROM is just a bunch of memory. You can't execute code on it. How would you use a ROM to control the LEDs? ROMs are hardly ever used nowadays anyway. If you need non-volatile memory, EEPROMs are the way to go. \$\endgroup\$ – Spencer Davis Feb 17 '14 at 1:39
  • \$\begingroup\$ I had the idea to use it and store a bunch of ASCII values on there and tell it to turn certain pins on or off depending on the ASCII code, from there I was going to use some NAND gates with open collectors to get all the data coming out of there to the right place. I know it's crude, but it's more of a proof of concept. However, the microcontroller seems a better route. \$\endgroup\$ – Tropical_Peach Feb 17 '14 at 3:28
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    \$\begingroup\$ Yea, doing that with a ROM would be incredibly difficult compared with just programming a microcontroller. An Arduino would work great for this since you mentioned that you had one. \$\endgroup\$ – Spencer Davis Feb 17 '14 at 4:05

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