Dot matrix display 7x5 LTP2157AE pin-out


I have been given a number of 7x5 dot matrix display segments. There are 7
pins at the top and 7 at the bottom. The ID on the segment is:
LTP2157AE
927 TAIWAN P
Can someone be kind enough to explain the pin-out for me.
R
Reply to
Roger Dewhurst
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Try an ohmmeter on diode test setting both ways.... could be common anode or common cathode
Reply to
BobG
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:
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ood luck Chris
Reply to
Chris
are 7
Thanks. This looks like an identical device!
Roger
Reply to
Roger Dewhurst
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
Reply to
Roger Dewhurst
[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.
Reply to
Randy Day
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
Reply to
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
Reply to
Roger Dewhurst

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