On Board EEPROM Write Read

[Peter1960]

Hello,
Aim -
To Read Status of Pins, A2 - A5 (4 bits)
Display on Other Pins, B4 - B7
Store Data in EEPROM Location 24 (Onboard)

Program 16F628a 4 mhz
*Usual Setups etc
ID var Byte
ID = 0
' Get Chip ID from PortA 2 - 5
If PortA.2 = 1 Then
ID = ID + 1
High PortB.4
EndIf
If PortA.3 = 1 Then
ID = ID + 2
High PortB.5
EndIf
If PortA.4 = 1 Then
ID = ID + 4
High PortB.6
EndIf
If PortA.5 = 1 Then
ID = ID + 8
High PortB.7
EndIf
Write 24,ID

If all ID were high I was expecting 0F in the location, however
the data pins showed correct, ie all high, but eeprom showed 0C.

Why?

Peter

[Peter1960]

Oh Dear!!!! Got caught again !!!
Trick for anyone reading this....
If you use a PIC chip with on board Analogue Inputs, ie
A0, A1, A2, A3 on PIC 16F628a,
Make SURE you add the line
CMCON = 7 ( Disable A-D, PortA = Digital)

Adding this line resolved the problem.

Actually I realised as I was typing the question before,
added the line in the program, and yep! all working.

Trust this will help.
thnks
Peter

[mister_e]

S.h.i.t. happen

BTW PORTA is always a problem source... nothing new if i say

• read datasheet
• you print this page

[Peter1960]

Thnks Steve.

Yep, the old saying R.T.F.M is always true.

Peter

[mister_e]

Hehe i try to stay as polite as i can

[Peter1960]

Sorry Steve, I did not mean to offend.

[mister_e]

I think it's the time to share that picture and laugh together... hehe i like it!!!