Mobile phone system LCD display problems

[Chris_xjtlu]

Hi friends,

Currently I am working with the mobile phone kit on a metal back plane.
There seems to be some issues with displaying characters on the lcd.
I have successfully uploaded Phone_03.fcf but the LCD is displaying characters with n and o only with 2 dots on top. see attached file.
Is there anyone that can shed some light on this? thanks

[Benj]

Hello Chris,

Are you using the new chip which I think is the 16F1937 or the old chip which is the 16F877A.

The 1937 requires a small mod to allow the LCD to work correctly.

Click the LCD component on the panel and select custom code from the properties toolbar.

Edit the defines function

Find this line

Code: Select all

#if MX_CLK_SPEED >= 32000000

And change to this.

Code: Select all

#if MX_CLK_SPEED >= 16000000

The LCD should now work correctly when you compile and download to the chip.

It's basically due to a 8-bit read -> modify -> write issue where the previous write has not yet appeared on the port so the next read overwrites it again.

[Chris_xjtlu]

Hi Benj,

You are right, I am using the new chip 16F1937.
I have changed the code that you mentioned and the problem has been FIXED.
I cannot begin to say how relieved and grateful I am. THANK you very much.
All these weeks of troubleshooting and that little issue lied there in that line of code.
I hope in the future the team can fix this lil issue for the new Chip.
You're the best.

Regards,

Chris

[Chris_xjtlu]

Oh one more thing Benj,

Do you happen to know why the microphone of the GSM board does not detect anything? using EB066-00-1
I have connect a headphone with MIC and Speaker jacks.
The speakers works fine and can detect what is being said from my own mobile phone.

[Benj]

Hi Chris,

Yep we are working on a better fix for the 16F19xx devices as this problem is annoying and should be automatically removed.

I think we messed up a bit for the mic circuit on the v1 EB066 board and it will only work with an active type mic e.g. a mic with a pre-amp.

The new v2 EB066 has resolved this issue.

[Chris_xjtlu]

Oh I see.. this will be a set back in the project then.
I checked the online costs of the pre-amp mic and it seems to be very expensive (from a student's point of view)
Are there any good affordable pre-amp headphones out there that you could recommend? what about the HP347 that MatrixM provides?
Because it was not included in the Kit when it was ordered and I haven't seen any details of the v2 GSM board online..