How to use Interrupt in PIC16F877A in C..??

koolguy

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• Mar 28, 2013

• #221

I will like to make at least 40x80 like this....

 

Ian Rogers

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• Mar 28, 2013

• #222

There is no reason why we can't use TWO ports for data 16 bit data That would speed things up..

 

koolguy

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• Apr 7, 2013

• #223

Here is the result of the animation code........
what is wrong i have connected the circuit as you said, but nothing is scrolling here and animating??


https://www.youtube.com/watch?v=4sNmLQD1AiQ&feature=youtu.be

 

Last edited: Apr 7, 2013

koolguy

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• Apr 7, 2013

• #224

Please what the problem all rows and portb is connecteda s you said!!
but it is not working!

 

Ian Rogers

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• Apr 7, 2013

• #225

What isn't working? My code on your hardware?... My code wasn't intended for your hard ware.... To run that code you'll need to re wire your rows for every forth row..

 

koolguy

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• Apr 7, 2013

• #226

Yes i have re-wire/updated as you suggested in previous post...
and you were saying of inverting the data in port B...

 

Ian Rogers

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• Apr 8, 2013

• #227

No.. That was in ISIS... The 8x8 matrix needed inverting....

According to the video, it seems to be nearly there... I would just recheck the wiring. the rows need to be like this to the shift registers..

....1...2....3...4... // row 1
....5...6....7...8...
...9...10..11..12..
...13..14..15..16..
..
..
...21..22..23..24.. // row 8

 

koolguy

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• Apr 8, 2013

• #228

hi
i have connected in this way the 8x32 led with 74164...

 

Ian Rogers

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• Apr 9, 2013

• #229

Do me a quick schematic and I'll get my code to work on your hardware..

 

koolguy

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• Apr 9, 2013

• #230

Here it is.......

 

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Ian Rogers

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• Apr 9, 2013

• #231

I thought so... Mines the other way round.. Scans from left to right... That's why you get reversed characters..

 

koolguy

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• Apr 9, 2013

• #232

So, i know again i have to change the hardware can't we change this from code?

 

Ian Rogers

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• Apr 10, 2013

• #233

Not really... The rows are just pulsed in sequence... Its the shift registers that control the row being updated...

If you write an algorithm that only supplies the correct data for each row pulse... Then your screen refresh routine will be inside the interrupt... And that's not good..

 

koolguy

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• Apr 10, 2013

• #234

Hi,

Scans from left to right... That's why you get reversed characters.

Click to expand...

I have done this but the problem is not solved don't know why???

and if we see the fault with the help of ball there are total 6 led for it which like this ' ", don't know whats the problem??

 

Ian Rogers

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• Apr 10, 2013

• #235

Are you using my un-changed code?... What shift registers are you using again?

I want to change my program to suit those shift registers..

 

koolguy

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• Apr 10, 2013

• #236

Are you using my un-changed code?... What shift registers are you using again?

I want to change my program to suit those shift registers..

Click to expand...

hi again,

I am using your code and 74164 registers....

 

Ian Rogers

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• Apr 10, 2013

• #237

OK!! I have changed the shift registers to the 74ls164's It works just as good



Check my connections with yours....

 

koolguy

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• Apr 10, 2013

• #238

Hi again,
I am using NPN transistor at port B with sinking that mean it is reversing the signal so, need to be changed by code!

 

Ian Rogers

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• Apr 11, 2013

• #239

Just change a line in the interrupt.

Code:

PORTB = buffer[displayPointer];

to

Code:

PORTB = ~(buffer[displayPointer]);

This will invert the output.

 

koolguy

Active Member

• May 3, 2013

• #240

Ian Rogers said:

No.. That was in ISIS... The 8x8 matrix needed inverting....

According to the video, it seems to be nearly there... I would just recheck the wiring. the rows need to be like this to the shift registers..

....1...2....3...4... // row 1
....5...6....7...8...
...9...10..11..12..
...13..14..15..16..
..
..
...21..22..23..24.. // row 8

Click to expand...

I am working on it...
i found that after scanning left to right i found the character mirror..
like this L is coming |- i mean to say on top...
so, the scanning should be from bottom now???