I2C with 16F628A mystery

[lilimike]

I am having some difficulty understanding the results I am getting, maybe it is due to something simple but I've been trying to figure it out for the past few hours.

I am using 16F628A reading and writing to 24LC16 and displaying results on LCD.
I am also using another application called PonyProg to read/write to my same EEPROM.

So here is the story;
I write to the 2416 these values:

for i2caddr = 0 to 2048 step 16
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$FF]:pause 10
next

then I read back the values and display on the LCD in this way:

i2caddr = 0
i2cread d1,d2,i2cdevice,i2caddr,[dat[0],dat[1],dat[2],dat[3],dat[4],dat[5],dat[6],dat[7],dat[8],dat[9],dat[10],dat[11],dat[12],dat[13],dat[14],dat[15]]
pause 10
errchk = 0
for i = 0 to 15
errchk = errchk + dat[i]
next
LCDOUT $FE,1
lcdout $FE,$80,dec errchk: pause 3000

Now I am expecting to get errchk = 741 but I get 716.
I cycled through each value after the addition within the loop and the last number to add up is 230 although the value I wrote was $FF = 255

Furthermore if I display on the LCD all values I see this:
1113c3c3c3c3c
3c888212121cc

but $cc = 204

Reading the content of 2416 with PonyProg shows properly:
01 01 01 3c 3c 3c 3c 3c 3c 08 08 08 21 21 21 ff


My code is not cleaned up because I was trying different ways but I always get to the same results I tried changing dat[] to word instead of byte but all the data gets messed up on the 2416.


@ __config _INTOSC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_ON & _LVP_OFF & _CP_OFF
clear
DEFINE OSC 4
TRISB = 0 ' Make PORTB all outputs
CMCON = 7 ' Disable comparator


Dat VAR byte[15]
I var byte
D1 var PORTA.2
D2 VAR PORTA.3
I2CAddr Var byte
I2CDevice var byte
ERRchk var word
OK VAR PORTA.4
;NOTOK var PORTA.5
ERRStatus var bit

LCD_DB4 VAR PORTB.7 ' Set port for 4 bits bus
LCD_DB5 VAR PORTB.6
LCD_DB6 VAR PORTB.5
LCD_DB7 VAR PORTB.4
LCD_RS VAR PORTB.0 ' Set RS bit port
LCD_E VAR PORTB.1 ' Set Enable bit port
LCD_Lines CON 2 ' # of Lines on LCD, 1 or 2 (Note: use 2 for 4 lines)
LCD_DATAUS CON 50 ' Data delay time in us
LCD_COMMANDUS CON 2000 ' Command delay time in us
INCLUDE "LCD_AnyPin.pbp" ' Must go after LCD initialization
Pause 500: LCDOUT $FE,1: pause 250 ' clear screen and relax

Start:

i2cdevice =160

LCDOUT $FE,$80,"Start"
pause 500

for i2caddr = 0 to 2048 step 16
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$FF]:pause 10
next

i2caddr = 0
i2cread d1,d2,i2cdevice,i2caddr,[dat[0],dat[1],dat[2],dat[3],dat[4],dat[5],dat[6],dat[7],dat[8],dat[9],dat[10],dat[11],dat[12],dat[13],dat[14],dat[15]]
pause 10
errchk = 0
for i = 0 to 15
errchk = errchk + dat[i]
next
LCDOUT $FE,1
lcdout $FE,$80,dec errchk: pause 3000


if errchk = 741 then ERRStatus = 0
i2caddr = 2032
i2cread d1,d2,i2cdevice,i2caddr,[dat[0],dat[1],dat[2],dat[3],dat[4],dat[5],dat[6],dat[7],dat[8],dat[9],dat[10],dat[11],dat[12],dat[13],dat[14],dat[15]]
pause 10
Errchk = 0
for i = 0 to 15
errchk = errchk + dat[i]
; LCDOUT $FE,1
; lcdout $FE,$80,dec ERRCHK: pause 2000

next
if errchk = 741 and errstatus = 0 then
high ok
pause 10000
low ok
else
lcdout $FE,$C0,dec ERRCHK
LCDOUT $FE,$80,hex dat[0],hex dat[1],hex dat[2],hex dat[3],hex dat[4],hex dat[5],hex dat[6],hex dat[7]
LCDOUT $FE,$C0,hex dat[8],hex dat[9],hex dat[10],hex dat[11],hex dat[12],hex dat[13],hex dat[14],hex dat[15]
endif

END

Thanks for any help.

Mike

[mister_e]

Dat VAR byte[15]

must be 16
</pre>

[lilimike]

Hi Steve,

Thank you...!

I tried changing it to 16 and my total is now as expected = 741
and also showing as FF on LCD.

But why should it be 16?
if Dat[0] is working then 0 to 15 = 16 addresses isn't it?


Mike

[mister_e]

an array that range from 0 to 15 is an array of 16 elements... hence the 16. Facile hein? ;)

[lilimike]

Ok that makes sens.

Actually I am feeling kind of stupid right now!
After a glass of wine I will be fine.

Un gros merci!

Mike

[FinchPJ]

Ok that makes sens.

Actually I am feeling kind of stupid right now!
After a glass of wine I will be fine.

Un gros merci!

Mike
BTW you defined I2CAddr as a byte, but treat it as a word (2048) - should be a word.
Peter

[lilimike]

This is an interesting observation, Thank you.

I wonder why it still works though!

Funny how sometimes a programming error is undetected by the compiler and then the program runs with unpredictable results and other times it just works!

Mike

[FinchPJ]

Further investigation has revealed why your checksum still worked.... (sorry for the rather brief earlier reply - it was from my mobile phone!). If we use the following code:


I2CAddr Var byte
Xray var byte
Alpha var byte
I2CAddr2 var byte
I2CDevice var byte

I2cdevice =160
I2CAddr2 = 0

for i2caddr = 0 to 2048 step 16
i2cwrite d1,d2,i2cdevice,i2caddr,[$55]
hserout [hex I2CAddr, " "]
pause 10
next


This reveals that with i2caddr as a byte, the for/next loop assigns the following values to I2CAddr:
0 10 20 30 40 50 60 70 80 90 A0 B0 C0 D0 E0 F0
then stops (whereas as a word continues up to 800 as expected).
So you are actually only writing to a memory address up to F0, but then reading back gives you the correct checksum. However where are you actually writing to memory? - Well the memory assignment by PBP is sequential in alphabetic order, words first then bytes, and the next byte after I2CAddr is in fact I2CDevice in your code, or in my modification, I2CAddr2, as is seen here:


_Alpha EQU RAM_START + 018h
_I2CAddr EQU RAM_START + 019h
_I2CAddr2 EQU RAM_START + 01Ah
_I2CDevice EQU RAM_START + 01Bh
_Xray EQU RAM_START + 01Ch



Now the PBP manual states "The Address size sent (byte or word) is determined by the size of the variable that is used. If a byte-sized variable is used for the Address, an 8-bit address is sent. If a word-sized variable is used, a 16-bit address is sent. Be sure to use the proper sized variable for the device you wish to communicate with."

I suspect this is in fact not correct and looking at the assembler code that PBP generates, in fact I2CWRITE seems to send a word, using I2CAddr, I2CAddr2 as the (word) address in my example, or the case of your code, actually I2CAddr, I2CDevice (=$A0) which is I suspect somewhere other than you intended in memory!
Peter

[lilimike]

Thank you Peter,

I understand the first part of your response but not sure about the second part:

Now the PBP manual states "The Address size sent (byte or word) is determined by the size of the variable that is used. If a byte-sized variable is used for the Address, an 8-bit address is sent. If a word-sized variable is used, a 16-bit address is sent. Be sure to use the proper sized variable for the device you wish to communicate with."

I suspect this is in fact not correct and looking at the assembler code that PBP generates, in fact I2CWRITE seems to send a word, using I2CAddr, I2CAddr2 as the (word) address in my example, or the case of your code, actually I2CAddr, I2CDevice (=$A0) which is I suspect somewhere other than you intended in memory!

I will continue to read it over and over, some times it takes me a few times to understand.

Now again I am running into some mystery and I wish I could understand better...

If I run this code:

i2cdevice =$A0
for i2caddr = 0 to 2048 step 16
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[$ff]:pause 10
next
Then I read the EPROM with Ponyprog and observed everything as expected.
5051

Then I rewrote my code by changing:

for i2caddr = 0 to 2048 step 16 to
for i2caddr = 0 to 1024 step 16 and the 3 first line I replaced $01 by $ff.

I was expecting to see half of the memory filled with my changes but it got filled all the way to address $7FF:
5050

The more I test the more I get confused!

Mike

[FinchPJ]

Actually I was wrong about the Addressing - I hadn't noticed you were using a 24C16 - I normally use larger chips - in fact the 24C16 needs a byte for the address. Unfortunately the addressing you require is a little more complex - the 2K memory is organised in 8 x 256 byte blocks and the A10, A9, A8 are conveyed as the lower 3,2,1 bits of the Control byte, and A7-0 in the Address byte - a rewrite of your addressing is needed!
Control Byte: 1010XXX0 where XXX are the high order 3 bits of the address
Address Byte: XXXXXXXX = A7-0
You will need to create the Control byte for each successive write. Get back to me if you need any more help.
Peter

[lilimike]

Ok so maybe I need more help.
There is obviously something I don't understand.:o

Looking at the 24CL16 datasheet:
5052

Based on this I changed the address to word and my understanding is:
Control byte = 1010 000 0 = $A0
I want to write $aa at address $400 so I wrote this code:


i2cdevice =$A0
i2caddr = $400

i2cwrite d1,d2,i2cdevice,i2caddr,[$aa]:pause 10

I was expecting to see only address $400 showing value $aa but this is the result:
5053

the value $aa is now showing at address $004 and at every next 16 locations all the way to 2048.

???

Mike

[FinchPJ]

I suggest you use a data array to send your bytes, and then you need to construct the ControlByte and address as in this example:


Dat VAR byte[16]
i var word
j var Byte
SDA var PORTA.2
SCL VAR PORTA.3
CntrB var Byte
Addr var byte
for i = 0 to 15
lookup i, [$01,$01,$01,$3c,$3c,$3c,$3c,$3c,$3c,$08,$08,$08,$2 1,$21,$21,$FF], j
Dat[i] = j
next
for i = 0 to $7F0 step 16 'End at 2048-16 = $7F0
CntrB = %10100000
CntrB.3 = i.10
CntrB.2 = i.9
CntrB.1 = i.8
Addr = i.lowbyte
i2cwrite SDA,SCL,CntrB,Addr,[str Dat\16]
pause 10
next


Peter

[lilimike]

ok I have created a new file and inserted your code with some of my code required for access to the EEPROM but when I run this code nothing gets written to the chip.

This is the complete code:

@ __config _INTOSC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_ON & _LVP_OFF & _CP_OFF
clear
DEFINE OSC 4
TRISB = %00001000
CMCON = 7 ; Disable comparator
OPTION_REG = 0

Activate var PORTB.2 ; 1 = access eeprom / 0 = normal operation
GO VAR PORTB.3 ; Start switch
OK VAR PORTB.4 ; Green LED
NOTOK var PORTB.5 ; Red LED

Dat VAR byte[16]
i var word
j var Byte
SDA var PORTA.2
SCL VAR PORTA.3
CntrB var Byte
Addr var byte

activate = 1



for i = 0 to 15
lookup i, [$01,$01,$01,$3c,$3c,$3c,$3c,$3c,$3c,$08,$08,$08,$2 1,$21,$21,$FF], j
Dat[i] = j
next
for i = 0 to $7F0 step 16 'End at 2048-16 = $7F0
CntrB = %10100000
CntrB.3 = i.10
CntrB.2 = i.9
CntrB.1 = i.8
Addr = i.lowbyte
i2cwrite SDA,SCL,CntrB,Addr,[str Dat\16]
pause 10
next
activate = 0
end

I've been struggling with this almost nonstop for a couple of days and I believe that either I think I am working with a 24LC16 chip and it is not or I have a hardware issue. The EEPROM chip is not visually accessible but my PonyProg application is detecting it as"2416" - Device type "2402-16"
This is my hardware and I ruled out any discrepancies between my drawing and actual PCB:
5054

Thanks for your time,

Mike

[lilimike]

sorry, Your code did write to the chip, what I did was to zero out the complete memory using this code:

I2CAddr = $0
I2CDevice = $A0
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr,[0]:i2caddr = i2caddr + 1:pause 10


Then I ran your code (as previous post) and I see that it wrote value FF on every 16th location from memory 0 to 2032 as such:
5055

Mike

[FinchPJ]

I am not familiar with PonyProg, are you using the SI-Prog baseboard hardware and the I²CBus eeprom adapter - I note that the adaptor does not have any pullup resistors on SDA and SCL and the baseboard does not provide these either - You have implemented the R2/R3 4K7 pullups shown on your schematic, havent you?? I have had many frustrating experiences with I2C Memory chips instantly solved by a pair of pull up resistors.

Failing this, I dont understand why the memory chip is visually inaccessible, but these results suggest you may not be dealing with a 24C16 chip - other chips may need different addressing.

[lilimike]

The chip is enclosed into a sealed device and the only thing exposed are the 4 pads for power and I2C. With trial and error... and trial and error over trial and error I managed to get what I need working. I know my program doesn't have much style but for now it does what it is supposed to do.

The process of my program is as follow:
When I press the switch I need to read address $04 and if it is > 5 it will flash the OK LED the number of the value found and then quit. If it is not greater than 5 then I want to set values $01,$01,$01,$3c,$3c,$3c,$3c,$3c,$3c,$08,$08,$08,$2 1,$21,$21,$FF all over.
I don't understand why I just write once and the chip gets updated all over but it works.

This device is hooked up to another device that will update the chip daily by setting address $04, $05, $06 to -1 each day.

I am definitely going to order some chips and test on breadboard until I get a good understanding of this.
In the mean time this is my working code:

@ __config _INTOSC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_ON & _LVP_OFF & _CP_OFF
clear
DEFINE OSC 4
TRISB = %00001000
CMCON = 7 ; Disable comparator
OPTION_REG = 0


SWSTAT var byte
Dat VAR byte
I var byte
I2CAddr Var word
I2CDevice var byte
D1 var PORTA.2 ; Cartrige white wire
D2 VAR PORTA.3 ; Cartrage blue wire
Activate var PORTB.2 ; select between reset=1 normal=0
GO VAR PORTB.3 ; Start switch
OK VAR PORTB.4 ; Green LED
NOTOK var PORTB.5 ; Red LED

activate = 0 ; Normal operation
ok = 0 ; Green LED off
notok = 0 ; Red LED off

goto swstatus

Start:

;--------make sure reset is needed-----------
activate = 1 ; get ready to reset
swstat = 0 ; reset switch debounce
pause 50 ; give time or relay contact

i2cdevice = $A1
i2caddr = 3
i2cread d1,d2,i2cdevice,i2caddr.lowbyte,[dat]
pause 10

if dat > 5 then
for I = 1 to dat
ok=1: pause 500:ok = 0:pause 500
next
activate = 0 ;------Resume normal operation
goto SwStatus
else

ok = 1: pause 3000: ok = 0 ; Green LED on for 3 seconds
pause 5000
I2CAddr = $0
I2CDevice = $A0

i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$01]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$3c]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$08]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$21]:i2caddr = i2caddr + 1:pause 10
i2cwrite d1,d2,i2cdevice,i2caddr.lowbyte,[$ff]:pause 10

;---------------------make sure data was written-------------------------
i2cdevice = $A1
i2caddr = 4
i2cread d1,d2,i2cdevice,i2caddr.lowbyte,[dat]
pause 10
activate = 0 ;------Resume normal operation
if dat = $3c then ;------all is good, flash green LED
for I = 1 to 10
toggle ok
pause 500
next
ok = 0
else ;------Something wrong, flash red LED
for I = 1 to 10
toggle notok
pause 500
next
notok = 0
endif
endif

SwStatus:
if go = 0 then debounce
swstat = 0
goto SWstatus

debounce:
swstat = swstat + 1
pause 10
if swstat = 150 then start
goto swstatus

END

Thank you for your help.

Mike

[mackrackit]

Have you seen/tried this?
http://www.picbasic.co.uk/forum/content.php?r=237-EEPROM-automatic-identification-routine

[lilimike]

Hi Dave,

I went a little too fast in my project, when I thought my circuit was good I built the PCB and dismantled my breadboard and its only after I saw this.

But thanks for the info

Mike