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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Wed Jan 15, 2014 12:22 pm Post subject: |
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Problem solved (kind of)
because there are no hours left in the project, this workaround.
cut the power supply track to the AVR.
insert 5V relay switch over the cut
connect the coil of the relay to the 5V supply (7805)
done!
happy it works ....the delay from the relay is enough to get it all working
sad that it has to be this way.
so the display gets 5V first and 5msec! later the AVR ......mind is blown.
Thanks for all your input guys!
maybe cheap displays are not so cheap in the end.
I am going to buy one farnell version of the 128x64 and have a look if that one works without all this trouble. |
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O-Family
Joined: 23 May 2010 Posts: 320 Location: Japan
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Posted: Wed Jan 15, 2014 1:43 pm Post subject: |
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That's too bad.
The solution irregular, there is a possibility that the trouble occurs again due to the noise and temperature later.
O-Family |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Wed Jan 15, 2014 2:50 pm Post subject: |
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I hope it does O-family
because then I get budget to repair it (it has to work a while though )
W. |
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O-Family
Joined: 23 May 2010 Posts: 320 Location: Japan
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Posted: Thu Jan 16, 2014 1:26 pm Post subject: |
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You need to answer condition correctly to a question.
Otherwise, neither the following test method nor advice can be proposed.
O-Family |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Fri Jan 17, 2014 8:25 am Post subject: |
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O-family,
Sorry I missed your question.
Yes it returns to normal after a push on the reset switch, but sometimes I have to push it several times?
if I power down ( oscilloscope probe on reset (pin 9 )) and power up before the voltage drops to absolute 0 (about 0.6V) then it allways 100% starts up.
Which watchdog timer do you mean?
Wilfred |
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O-Family
Joined: 23 May 2010 Posts: 320 Location: Japan
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Posted: Fri Jan 17, 2014 10:30 am Post subject: |
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If a reset switch is effective during freezing, it does not have influence of a watch dog timer.
If a multiple push is necessary for reset, I think that the reset of the LCD does not succeed.
When freezing, can the following waveforms be seen with an oscilloscope?
Check 1
CH.1 VDD (trigger of power-on)
CH.2 LCD /RST pin
Check 2
CH.1 LCD E (trigger)
CH.2 LCD DB7 pin
Check 3
CH.1 LCD E (trigger)
CH.2 LCD DB4 pin
O-Family |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Fri Jan 17, 2014 3:08 pm Post subject: |
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See my earlier posts ( i will measure your question tomorrow or tonight)
when the display doesnt't start a square wave is visible on most data lines with frequency 145 kHz
on E-pin ( the duty cycle is different but also 145 kHz.
W. |
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O-Family
Joined: 23 May 2010 Posts: 320 Location: Japan
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Posted: Fri Jan 17, 2014 3:48 pm Post subject: |
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When the edge of E clock is reading, I would like to know whether a data bus is high or low.
(DB4 and DB7) |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Mon Jan 20, 2014 10:32 am Post subject: |
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Good morning (evening) gentlemen,
O-family here are the pictures you asked
1ste 3 pictures are not booting
last 2 pictures are booting while I slowly increase voltage ( the slanting line )
I hope this helps you
Wilfred |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Mon Jan 20, 2014 10:35 am Post subject: |
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hmmm can only post 3 pictures at once
here are the last 2
these are when the system starts ok
Last edited by Wilfred on Mon Jan 20, 2014 1:27 pm; edited 1 time in total |
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Evert :-)
Joined: 18 Feb 2005 Posts: 2156
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Posted: Mon Jan 20, 2014 10:55 am Post subject: |
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The E line in picture 1 and 2 looks not that nice, high is 2.5V and low is 0.8V.
Measure on the avr the E line with the wire to the display lose to see if it's better then. _________________ www.evertdekker.com Bascom code vault |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Mon Jan 20, 2014 1:04 pm Post subject: |
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Wow Evert
my channel 1 of the o-scope is damaged!
First i thought it was the signal but then I switched channels
and the signal was 0 - 5V
so it is the scope! the signals are ok ...will try again tomorrow
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Evert :-)
Joined: 18 Feb 2005 Posts: 2156
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Posted: Mon Jan 20, 2014 1:45 pm Post subject: |
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If it's your scope broken and image 1&2 are oke then image 5 is not oke, because both channels are here 5V. _________________ www.evertdekker.com Bascom code vault |
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Wilfred
Joined: 15 Jul 2010 Posts: 40
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Posted: Mon Jan 20, 2014 1:46 pm Post subject: |
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O-family
it seems that my scope has something wrong with it ( all the S*** happens at the same time )
this picture is DB7 =blue and E in Yellow
the amplitudes are both 5 V
this is while not booting . |
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O-Family
Joined: 23 May 2010 Posts: 320 Location: Japan
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Posted: Mon Jan 20, 2014 2:02 pm Post subject: |
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A probe is damaged?
So why the waveform of the /RST signal, whether the 5V both?
As for me, E clock seemed to short-circuit with other signal lines.
I want to see a longer time, the waveform of the /RST pin of [Check 1].
(until it can check a LCD /RST signal)
O-Family |
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