How to store SHT11 data in eeprom?

[dinhthi]

Hi,
I'm having project about humidity and temperature measurment and I'm using sht71. My code has used the file SHT.c and it works perfectly
but I have a little problem. I want to store humidity and temperature values in epprom 24c512. Each storage, address increase by one. I was wondering how not to lose address value when I reset (hard reset and soft reset).
Please help me, thanks.

[PCM programmer]

This demo program may help:
http://www.ccsinfo.com/forum/viewtopic.php?t=22109&start=17

[asmboy]

The program above is a great demo but copying it and using the concept
blindly- "as is" - can lead to design failure:

Namely the fact that the EEPROM storage address is in a random state after you program the PIC.

This is unacceptable for a delivered product .

One answer is to program the user space with a known default
as part of the PIC program process

Many program fixtures will let you do this - once you suss it out

Another answer that i prefer is to start with a seed of 0Xc5c5 ( int16 chk)
and create an additive checksum from, one or more bytes that i write to eeprom then the checksum follows the data you write

While there is a 1 in 0x10000 of this passing when it should not -
it has never let me down.

and all you have to do is make sure that adding the bytes you readback
to the initial seed value = equals the 2 byte checksum you read - following the data

and if you read back un_inited or corrupted_from_too_many_writes EEPROM - the checksum test will warn u




CHARS

[PCM programmer]

It's not random. It's initialized to zero by this statement:

[rnielsen]

Whenever I need to keep track of how much data I've written into an eeprom, I will save one address, of the eeprom, to store the last address written to. That way, when I reset or cycle power, I simply read that address and find out how much data was written and I can reassemble the data properly. It could be the last address that is available. Just make sure your program doesn't overwrite it with data.

Ronald

[asmboy]

In my comments about init an checksum /CRC of EEPROM
I should have seen the INIT example - which is nice; and in a well integrated way - lets an initial value be set.

The comments about checking validity of eeprom data you write are worth serious consideration - if you are doing programming that MUST rely on the correctness of he EEPROM.

[andys]

If you use a flash memory is anything different or you can use the same code?