LCD serial backpacks

[Darrel Taylor]

flipper_MD,

Are you a doctor, cause I've got this pain in my ...
Oh ... you're probably a porpoise doctor

Ummm no, I don't really see a reason for problems disabling at that point.

The closest thing to a problem I can see is that the GrabBkLt command will take over 3ms to display the LCD data ... 2ms for the command and 20+ chars at 50us delay = 1ms.

3ms by itself shouldn't be a problem, and it should only happen infrequently, but it's the closest thing to a problem I can see at first glance.

What are the symptoms?

[flipper_md]

Apparently, It will lock the PIC from receiving commands, if external data is received before it enter the main loop.

Visually, It will flash the LED, show "LCD Serial - READY", but stop there and not respond.


may I suggest Dr Pepper ?
Sugar is food for the brain

[timseven]

Yes Mr. Taylor I can't forget Joe S. as this backpack originator, I am sorry.

Well, I am almost there. I had some lines modified to the program to adapt it to my hardware. I modified:
DEFINE LCD_LINES from 4 to 2. ‘My LCD is 2X20
DEFINE OSC from 20 TO 4 ‘My 628 is 4 Mhz
DEFINE HSER_SPBRG from 32 to 25 ‘My 628 is 4 Mhz
The rest is unchanged.
When I turned it on I got the “Your text goes here” message and then over it a second later I got “Clearing display buffer” error. It’s something else that I need to change on the program to prevent the buffer to overrun? Thanks.

[Darrel Taylor]

Change TXSTA to ...

DEFINE HSER_TXSTA 24h

9600 baud at 4Mhz needs the BRGH bit set to 1 with SPBRG = 25.

[timseven]

I did the change on “DEFINE HSER_TXSTA from 20H to 25H and tested with same error. I restored all the DEFINES back to its original values (DEFINE OSC 20, DEFINE HSER_TXSTA 20H, DEFINE HSER_SPBRG 32) and used this time a 628-20 Mhz chip. I got the same error “Cleaning Display Buffer”. Any suggestion?

[Darrel Taylor]

Maybe it was just a typo, but TXSTA should have been changed to 24h, not 25h. But it probably wouldn't matter.

And when you say "and used this time a 628-20 Mhz chip"...
Do you mean that you used a 16F628 with a 20Mhz crystal and two 15-33pf capacitors?

[flipper_md]

Tim,

are you sending data to the screen to see if the message will clear out?

I always see the clearing display message at start, but everything works fine when I send data (without my silly Disabled Interrupt trial..of course).