Driving LED DOT Matrix with ULN2803 and 74LS138

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jean12

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Hello there ,can you please help me to drive those dot matrix by proving a drive ULN2803 bebween the 74LS138 and DOT MATRIX.
I tried to do that but I failed.Please help.

without the drive the circuit operates very well in simulation but on the board with physical implementation;it doesn't work,I just see some column shifting.

See my project here attached.
 

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  • FOLDER.zip
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If you put ULN between 54LS183 and matrix then you have to interface cathodes with ULN because ULN can only sink current. Rotate the matrix 180 degree and then flip along x - axis. Now you can connect cathodes to ULN. The data will be inverted. So, invert your matrix array elements.

Edit: I was wrong. He is shifting 0x01 at the o/p of LS138. So, you don't have to change anything with the matrix. Just put a NOT gate abd ULN between LS138 and matrix.
 
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with post #2 above he said that the ULN is inverting the input so the LED are not working as they might so he said I have to connect a NOT gate before I put the ULN for reinverting those output.

Thanks.
 

Dear jayanth.devarayanadurga, here is the complete folder for the proteus schematic and ccs c file.


Thanks.
 

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