Write and Read from internal Memory

[Pic_User]

Thank you for the great sample, Melanie.

The comments make it a real tutorial on reading and writing to EEPROM. The logic and flow are a glimpse into the world of how professionals write code. Very impressive.

I will be studying this masterpiece for some time to come.

-Adam-

[ria_river]

Hi Melanie!

Is the sample.bas that you posted about how to read and write the EEPROM applicable for 16F877A?

If not, what certain modifications should be done?

Please help...

ria

[Melanie]

Adam - *blush* personally Signed framed Masterpieces are available in exchange for internationally negotiable crinkly drinking vouchers...


Ria - Yes it is, with a few changes...

1. Change ALL the PIC defines to 877A instead 876A...

eg

@ DEVICE pic16F876A, XT_OSC

becomes

@ DEVICE pic16F877A, XT_OSC

2. Add additional TRIS statements to account for Ports D and E.

eg

TRISE=%11111111

Remembering that parts of PortE will still have Analog on them...

3. Compile with the command line

PBPW -p16f877A sample -v

[ria_river]

I see..
Thank you so much Melanie..

I really learn a lot from this forum.

Cheers!

ria

[ria_river]

By the way Melanie..why we need to use PBPW instead of PBP in compiling?

What's the difference between them?

[joseph Degorio]

Hi Melanie,
I got your code running, initially I placed '9999' at memory location 0. I'm trying
to read it from the internal memory, So I try this code below. But when I press the button I got '655535'
instead the initial value '9999'.



TRISB=%00010000 ' All PortB is Output - except
' B.3 = Button
TRISC=%00000000 ' All PortC is Output
CMCON=%00000111 ' Disable Comparators
CVRCON=%00000000 ' Disable Reference Module
OPTION_REG.7=0 ' Enable Weak Pull-Up's
Pause 2000
ButtonPRESS var PortB.4 ' Push Button
WORDVariable var WORD

PromptLoop:
Serout PortC.1,6, [$FE,1,"Press Button..."]
While ButtonPRESS=1:Wend ' Wait here until Button Pressed
READ 0,WORDVariable.HighByte ' Reconstruct Word variable from EEPROM
READ 1,WORDVariable.LowByte
Serout PortC.1,6, [$FE,1,"Reading=",#WORDVariable] ' Display Result
While ButtonPress=0:Wend ' Wait here as long as finger is on Button
Goto PromptLoop
'
End

Thanks for the time, appreciate it very much,
joe

[mister_e]

Make sure your PIC programmer program the EEPROM location, unless.. you may read an empty EEPROM $FFFF

Now depending of how you wrote your DATA line, this may work.. or not.

data  @0, WORD 9999

should work.

Your PICProgrammer software should allow to see the EEPROM section, just compile your code, import the .HEX and look if your data is saved in the EEPROM.