LCD1602 questions [SOLVED]

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mb101
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LCD1602 questions [SOLVED]

Postby mb101 » Sat Jul 13, 2013 7:58 am

Hi,

I'm having trouble getting an LCD1602 to work, can someone confirm the attached is the correct waveform just to eliminate anything? It correct to the data sheet and I never had issues in the past with this component!
I'm using a PIC, configured to RC clock running at 1MHz. I have checked with two LCD modules which I believe to be working.

Any thoughts or suggestions for me to try?

Thank you in advance for any help :)

Mark
Attachments
LCD1602.gif
LCD Trace
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Last edited by mb101 on Fri Jul 19, 2013 4:30 pm, edited 1 time in total.

brandonb
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Re: LCD1602 questions

Postby brandonb » Sat Jul 13, 2013 8:18 am

rs should be low when sending a command and high when sending characters, in yours i don't see that, every time enable double pulses it has sent two nibbles (one byte), it doesnt appear that A0 is working correctly

mb101
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Re: LCD1602 questions - SOLVED

Postby mb101 » Sat Jul 13, 2013 11:57 am

brandonb wrote:rs should be low when sending a command and high when sending characters, in yours i don't see that, every time enable double pulses it has sent two nibbles (one byte), it doesnt appear that A0 is working correctly

Hi,

thanks for the hints :)

I dug a bit deeper and I had the following issues -
1) the ground was floating at 2.2v on my dev board for the LCD only - that's why it pays to get a decent dev board :mrgreen:
2) the RW line was driven to 5v, must be low (it's not used by the flowcode functions).

Yes you're right the RS line is low for control chars and toggles High when it's writing data to RAM (on the lcd) - the original trace I posted included the control chars setup at the start, I should have said :oops:

Thanks again :-)