Hand Held Prototyper

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tonyd
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Hand Held Prototyper

Post by tonyd » Thu Jan 02, 2014 5:53 pm

Just finished the assembly but I can't get the screen to display anything. The contrast is the only thing that works and shows one line ( not two as expected )of rectangles where text should be. The serial monitor shows me that at least the switches work but again nothing on the display. Any help would be appreciated

Tonyd

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joepardue
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Re: Hand Held Prototyper

Post by joepardue » Fri Jan 03, 2014 1:11 pm

If the serial monitor is showing which button gets pressed then most of the circuit is good and the ATmega328 is working okay. I'd take a careful look at the soldering on the LCD header both the male pins on the LCD board and the female pins on the I2C Mini Terminal board. Maybe resolder all those pins just to be sure. If that doesn't work then please send the board to me and I'll see if I can fix it. Send your address to me at joepardue at hotmail dot com and I'll send you address to send the board too.

Sorry you are having problems with this.

Joe

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Re: Hand Held Prototyper

Post by tonyd » Sun Jan 05, 2014 7:23 am

Joe,
Thank you for the reply. I did recheck and re solder the connections from the ATmega328 to the display header. I also checked continuity between the ATmega328 and the display header and they wee all OK. I also tried wiring the display using the individual pins instead of the serial interface and it still did not work. The display seems to blink or flicker and if you change the loop time you can see the display change accordingly but still no characters. I may just go ahead an order a new display this week when I order some parts for another project.

Thank,
Tonyd

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joepardue
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Re: Hand Held Prototyper

Post by joepardue » Sun Jan 05, 2014 11:14 am

Sounds like a plan. But do remember that if you want to mail it to me, I'll take a look.

Joe

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Re: Hand Held Prototyper

Post by tonyd » Thu Jan 09, 2014 10:16 am

Joe,

I'm all set, the new display fixed it. Thank you for you help and now I can actually start playing with it.

Than you,
Tonyd

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Re: Hand Held Prototyper

Post by wishart » Mon Mar 24, 2014 9:29 am

I am also experiencing a similar problem with my miniterminal display. When I apply power, I see only one row of eight character-sized rectangular blocks. If I adjust the contrast pot, the blocks get darker or dimmer. When I run the Arduino test program, there is no apparent response on the display, but the serial monitor prints the line "mini_terminal_master 0.01". If I press the buttons on the miniterminal board, there is no response on the serial monitor.

I have checked for solder bridges & bad solder joints and didn't find any. (Wife's opinion: "I know how you look.":>)

Any suggestions as to what the problem might be?

Thanks,
John

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joepardue
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Re: Hand Held Prototyper

Post by joepardue » Mon Mar 24, 2014 3:42 pm

Well, I'd reheat all the solder joints, especially on the ATmega328 socket and the LED headers and see if that fixes it. Since you are getting the serial monitor feedback then most of the joints are okay. I really can't think of any other cause for the problem, but I'd be happy to take a look at the board if you want to send it to me.

Joe

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Re: Hand Held Prototyper

Post by wishart » Wed Mar 26, 2014 8:08 am

Thanks. I will reflow solder joints and see if that fixes it.
John

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Re: Hand Held Prototyper

Post by wishart » Sat Apr 19, 2014 3:09 pm

I finally got time to reflow all the solder joints on all boards. No change in behavior -- still just getting 8 dark blocks on the LCD, with the backlight coming on. No response from any of the buttons. Guess I'd better return it for your evaluation.
Regards,
John

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joepardue
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Re: Hand Held Prototyper

Post by joepardue » Sat Apr 19, 2014 6:31 pm

John,

Sorry you are having a problem with this, but I'm happy to look at it.

Send it to:

Joe Pardue
5601 Timbercrest Trail
Knoxville, TN 37909

wishart
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Re: Hand Held Prototyper

Post by wishart » Mon Apr 21, 2014 6:52 am

Thanks, Joe. I will send it back shortly.
John

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joepardue
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Re: Hand Held Prototyper

Post by joepardue » Tue Apr 29, 2014 9:08 am

John,

Well something happened to the application program on the I2C Mini Terminal. I tested your circuit with a known good ATmega328 with the correct program and it worked so you didn't do anything wrong with the construction. Interestingly, I test all the chips before marking them, but for some reason the one one your system no longer worked properly, however the bootloader still worked so I can't think of any way the application could have gone bad only for the LCD but not for the pushbuttons. I'm going to chalk this one up to 'weirdness' and move on.

I'll ship the system back to you ASAP.

And sorry for the inconvenience.

Joe

wishart
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Re: Hand Held Prototyper

Post by wishart » Tue Apr 29, 2014 11:10 am

Thank you, Joe, for the rapid response. I'm glad that it was (relatively) easy to correct the problem w/o any parts replacement or resoldering.
Regards,
John

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Re: Hand Held Prototyper

Post by wishart » Mon May 05, 2014 6:46 am

Received the HHP back on Sat. It is working fine now. Thanks, Joe.
John

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