PR29

LED Blinking, Walking with Cytron Servo, Displaying RFID, Multi-function Mobile Robot......

PR29

Postby mark » Mon Feb 13, 2012 11:02 pm

I have already fix everything on breadboard but only the back light lit up. There is no display. Any idea?
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Re: PR29

Postby ABSF » Tue Feb 14, 2012 9:16 am

Looks like you fixed everything except the problem! :lol:

Have you programmed the PIC?
Are you sure all the wires on your breadboard are all correctly connected?
Is your power supply OK?
Is the +5V present on all the points that require it?
Is your LCD display tested working somewhere else?

These are just some of the things you have to find out before you insert your PIC onto the breadboard.
Post a picture would invite more help... 8-)

Allen
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Re: PR29

Postby mark » Tue Feb 14, 2012 9:48 am

Its quite a mess because I have to fix it on breadboard to show our lecturer that it's working then only we can solder it on pcb.

Have you programmed the PIC? Yes
Are you sure all the wires on your breadboard are all correctly connected? Yes, my lecturer took everything out and fix it and its still the same
Is your power supply OK? yes
Is the +5V present on all the points that require it? checked
Is your LCD display tested working somewhere else? i've tried
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Optimized-IMG_1114.JPG
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Re: PR29

Postby ABSF » Tue Feb 14, 2012 11:41 am

Your LCD covers up most of the things around the PIC which is an important part we want to see. Try to take the picture from the top instead of from the side.

Since you said the back lite is working, I assume the +5V is OK. Is your back lite too bright and the contrast of LCD too low that you're unable to see the text on it?

Do you have an Oscilloscope or logic probe for trouble shooting? The MCLR pin should be Low to High and stay High when +5V is applied to the PIC. The 8 wires from port B to the LCD DB0-DB7 should have good continuaty and the E and RS should detect pulses during activities. Since your PIC is programmed externally you may connect RB6 and RB7 directly to the LCD without going through 1K resistors.

During troubleshooting, you dont need the finger-print device so you may remove it temporarily to reduce the mess. Try to add 0.1uF on the +5V to gnd at the output of 7805.

Allen
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Re: PR29

Postby shahrul » Tue Feb 14, 2012 5:29 pm

For me, make sure LCD part is function first. Because, the output is clearly tell what the status. So,
1. Check all the requirement supply voltage.
2. Check the LCD connection first
If me blank in this situation, I will take out first others component not related to LCD.
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Re: PR29

Postby mark » Tue Feb 14, 2012 9:53 pm

Since you said the back lite is working, I assume the +5V is OK. Is your back lite too bright and the contrast of LCD too low that you're unable to see the text on it? adjusted but only see black boxes

Do you have an Oscilloscope or logic probe for trouble shooting? The MCLR pin should be Low to High and stay High when +5V is applied to the PIC. The 8 wires from port B to the LCD DB0-DB7 should have good continuaty and the E and RS should detect pulses during activities. Since your PIC is programmed externally you may connect RB6 and RB7 directly to the LCD without going through 1K resistors. done

During troubleshooting, you dont need the finger-print device so you may remove it temporarily to reduce the mess. Try to add 0.1uF on the +5V to gnd at the output of 7805. done but still the same
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Re: PR29

Postby mark » Tue Feb 14, 2012 9:55 pm

1. Check all the requirement supply voltage. checked
2. Check the LCD connection first checked

Changed the IC. Didn't work either. Planning to get a new LCD tomorrow.
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Re: PR29

Postby ABSF » Wed Feb 15, 2012 8:48 am

Should be hardware or wiring problem. I simulated the cct on Proteus and it worked. The text message appears for a few seconds and then shows a blank screen. It will appear again when the RESET is pressed.

PR29A.JPG
PR29 simulated on proteus


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Re: PR29

Postby mark » Wed Feb 15, 2012 9:13 am

I will buy a new LCD later and try it first.

Anyway after the "Cytron PR29" appear on the LCD, it should have 1.Admin Login and 2. User Login right?
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Re: PR29

Postby ABSF » Wed Feb 15, 2012 9:37 am

Nop.... if you look at the software, after displaying the text, the 876a is sending command to the FP device and waiting for the reply. AFter the FP device replied, the message you mentioned would only then be displayed.

As i am unable to simulate the FP device, so my simulation just stopped there.

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