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GPUtils PIC bug?

gputils pagesel bug

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#31 +Karl L.

Karl L.

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Posted 15 July 2013 - 21:30

In that case I'm really not sure what the problem is. It sounds like you have your hardware setup correctly, but don't rule anything out too quickly. I have spend hours debugging my software just to discover that I had a bug in my hardware that "couldn't possibly happen", so I ruled it out hours before. (I have also had the same problem vice-versa. It's just part of microcontroller development, I think.) It doesn't sound like a power issue. The 11mV difference on your rail shouldn't be a problem; current draw is really what you should be looking at anyway.




#32 OP n_K

n_K

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Posted 15 July 2013 - 21:39

Haha I cannot actually believe this, fixed it. Replaced the 7805 with a LM2940CT-5 and behold it's working fine with the correct baud rate.

I started thinking there was something fishy with the regulator, put the LCD backlight and RFID reader power on transistors and it worked fine from the 5V rail but the 7805 regulator just made the screen backlight continually flash on and off in short bursts and wasn't powering the RFID reader or PIC.

Not sure what's up with the regulator, it's an official texas instruments one, well, the packaging states it is anyway. Picture is rubbish but here's a pic of the regulators, the TI 7805, 2*NI LM2940's and a Motorola 7905;

Ggj8gsS.jpg

Definately an interesting problem I've never seen or had before.



#33 +Karl L.

Karl L.

    xorangekiller

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Posted 15 July 2013 - 23:16

Haha I cannot actually believe this, fixed it. Replaced the 7805 with a LM2940CT-5 and behold it's working fine with the correct baud rate.

I started thinking there was something fishy with the regulator, put the LCD backlight and RFID reader power on transistors and it worked fine from the 5V rail but the 7805 regulator just made the screen backlight continually flash on and off in short bursts and wasn't powering the RFID reader or PIC.

Not sure what's up with the regulator, it's an official texas instruments one, well, the packaging states it is anyway. Picture is rubbish but here's a pic of the regulators, the TI 7805, 2*NI LM2940's and a Motorola 7905;

 

I'm glad you solved your problem. Faulty hardware will do it every time. Now I recommend that you check your circuit to make sure you don't have a short. I have blown a voltage regulator or two that way. It never hurts to be too cautious.

 

Also if I ever need to make my eyes water and am lacking onions to slice, I will come back to this thread and look at that picture.



#34 OP n_K

n_K

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Posted 16 July 2013 - 15:34

I'm glad you solved your problem. Faulty hardware will do it every time. Now I recommend that you check your circuit to make sure you don't have a short. I have blown a voltage regulator or two that way. It never hurts to be too cautious.

 

Also if I ever need to make my eyes water and am lacking onions to slice, I will come back to this thread and look at that picture.

Haha the pics not THAT bad... well maybe it is...

I double checked and there is no short, it's using a PC power supply as the power source anyway and that automatically turns off supply power if there is a short (done it a few time accidentally on the 3.3V and 5V lines ;x).





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