Dot matrix display 7x5 LTP2157AE pin-out

Try an ohmmeter on diode test setting both ways.... could be common anode or common cathode

Hi, Roger. Can't find the part -- I'd guess you might have to get out your DMM and use the diode tester.

Here's a standard pinout that might help:

ood luck Chris

are 7

Thanks. This looks like an identical device!

Roger

>

are 7

I have printed out the document but how do I work out what the pins do.

I can see that there are 8 anode pins and 6 cathode pins but that is about as far as I get.

R

[snip]

Connect 3 to 5 volts (through a current-limiting resistor), negative to one cathode, positive to each anode in turn; each time a different spot should come on. Move neg. to the next cathode, then pos. to each anode again - different spots come on.

R |-----/\\/\\/\\--- cathode -

--- 3-5VDC |-------------- anode

Choose the resistor value to limit current to

25mA. As the small schematic in the doc with all the diodes shows, they're arranged in a row-col matrix.

Hi, Roger. Driving the displays you have might not be the easiest thing for a newbie. They work on the time multiplexing principle. If you apply 7 bits of data to the anode pins, and then activate one of the cathode pins, one row of the diplay will light. By using a computer or microcontroller amd appropriate high current latching drivers, you can scroll across the rows at a fast rate (say, 1000 times a second or so), and due to persistence of vision it will appear that all the rows are on at once. A typical microcontroller can easily handle this and also take care of other things such as maintaining a communications link and taking care of other business.

But unless you've got that microcontroller, it is going to be really difficult to get a whole lot of use out of your display.

Good luck Chris

There

about

Thanks. I just wanted to use them to display a time in milliseconds between two events. Since I got a bunch of these 7x5 LED matrix devices I thought that I might try and use them. Obviously there are easier ways.

Roger