Embedded_Geek
Full Member level 6
Once i faced this problem in simulation but it worked on real hardware
Once i faced this problem in simulation but it worked on real hardwareI don't know if its the simulation model or if I'm doing something wrong.
Yes your design has rows =cathode and column=anode.
I don't know why but everything i have tried with your design doesn't work, very strange.
The PNP emitter follower should have worked, I don't know if its the simulation model or if I'm doing something wrong.
Alex
This should have worked but it didn't
View attachment 52526
the specific transistor is not important in simulation, and you will also need to add the resistors for the real design.
Alex
in that manner can it sink my rows sir?
you need a common source for current
proteus isnt so hard
i made these models you need in leds matrix
labcenter made a poor copy
do you need them #? pm me
This is why i suspect a simulation problem,
also when i drive the transistor base and columns manually it works (using LogicToggle component)
Alex
Once i faced this problem in simulation but it worked on real hardware
how do i sink my column?
send to the 74hc595 an inverted byte (~0xF0) becomes (0x0F)
Alex
i wont use any ULN to my 595?
To simulate a led matrix with the reverse polarity (row=anode, column=cathode) double click the led matrix component ,
check "edit all properties as text " and replace {INVERT=A,B,C,D,E,F,G} with {INVERT=1,2,3,4,5}
Alex
---------- Post added at 17:08 ---------- Previous post was at 17:05 ----------
I'm not talking about a ULN chip, I'm taking about your C program in the mcu,
send the inverted serial bytes, use ~ in front of each byte to transmit the reversed byte.
Alex
To simulate a led matrix with the reverse polarity (row=anode, column=cathode) double click the led matrix component ,
check "edit all properties as text " and replace {INVERT=A,B,C,D,E,F,G} with {INVERT=1,2,3,4,5}
Alex
---------- Post added at 17:08 ---------- Previous post was at 17:05 ----------
I'm not talking about a ULN chip, I'm taking about your C program in the mcu,
send the inverted serial bytes, use ~ in front of each byte to transmit the reversed byte.
Alex
You seem confused, let me explain,
when you transmit a serial byte to the 595, for example 0b11110000 this is what the output will show 11110000,
to invert it you can send ~0b11110000 (which is actually 0b00001111) and the output will be the 00001111, the reverse of the above output.
You can't provide the current for the led's directly in either the anode of cathode because you have 5 and 7 leds, you need to use transistors or a ULN chip
but this nothing to do with the way to invert your byte (and 595 output).
Alex
---------- Post added at 17:29 ---------- Previous post was at 17:21 ----------
I don't think you can name a matrix display that way , there is no common like in a 7 segment display,
it is a set of independent anodes and cathodes connected in a matrix.
I suppose you can select to buy a display with the anode in the rows or in the columns but that doesn't name it common ...
Alex
I haven't used any matrix display but your circuit seems to be ok,
you just have to drive the leds using resistors to limit the current and with devices that can handle the current for the lest (ULN or transistors).
About your programming, I don't use pic at all i only use avr's but in any case it wouldn't be possible for someone else
to make your project, if you need help in specifics we will try to help if we can.
Alex
You seem confused, let me explain,
when you transmit a serial byte to the 595, for example 0b11110000 this is what the output will show 11110000,
to invert it you can send ~0b11110000 (which is actually 0b00001111) and the output will be the 00001111, the reverse of the above output.
You can't provide the current for the led's directly in either the anode of cathode because you have 5 and 7 leds, you need to use transistors or a ULN chip
but this nothing to do with the way to invert your byte (and 595 output).
Alex
---------- Post added at 17:29 ---------- Previous post was at 17:21 ----------
I don't think you can name a matrix display that way , there is no common like in a 7 segment display,
it is a set of independent anodes and cathodes connected in a matrix.
I suppose you can select to buy a display with the anode in the rows or in the columns but that doesn't name it common ...
Alex
PNP can be connected to the cathode to sink (collector to gnd) and is turned on with a low (0) in the base,
it depends on the matrix you are going to use , cathodes can be in the rows or columns.
ULN2003 should work too, it can ground (sink) the cathodes but with a high in the input (1) and not low as the PNP.
Alex
---------- Post added at 18:00 ---------- Previous post was at 17:57 ----------
I don't understand what you mean by common, you have to be able to light any of the 30 leds (dots) individually,
this is not possible with a common and 7 control lines, you need 5x7 control lines.
Alex
I have some link love from some projects :
**broken link removed**
I have some link love from some projects :
**broken link removed**
**broken link removed**
sir i dont know how to download your projects
**broken link removed**
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