Problem using function write_eeprom() in 18F97J60 *** Locked

[orazio]

Excuse me, I'm using CCS 4.084 compiler and PIC 18F97J60.
I want write to eprom using function write_eprom().
When i try to compile i have following error:
Undefined identifier -- write_eeprom

could anyone say to me if PIC 18F97J60 have eprom and why doesn't support write_eprom() function?

When i use CCS 4.084 compiler and PIC 18F8723, write_eprom() function is compiled correctly.

thanks in advance

[RF_Developer]

[orazio]

OK RF_developer thank you for the clarification.

Another question.
Suppose that i install bootloader in a PIC18 with eproom.
Suppose that on power-on, i enter in bootloader section and i install via RS232 myapp.hex. After installation, the PIC reset and start with myapp.he.
Suppose that myapp.hex save data in eprom.
If i re-install myapp.hex using bootloader, after installation and PIC reset do i lose my data saved in eprom?
Or they remain saved in eprom?

Thanks in advance.

[orazio]

Hey Forum Moderator non ti incazzare.
Don't worry. Stay well!!!
Ok i spell eeprom. Ary you happy now?
Do not make me lose time and let me talk to the people's forum.



People's forum, exucuse me, i'd like to know information about BOOTLOADER IN PIC18 with eeprom and mantaining data in EEPROM when i re-install myapp.hex using bootloader.

Suppose that i install bootloader in a chip PIC18 with eeproom.
Suppose that on power-on, i enter in bootloader section and i install via RS232 myapp.hex. After installation, the PIC reset and start with myapp.hex.
Suppose that myapp.hex save data in eprom.
If i re-install myapp.hex using bootloader, after installation and PIC reset do i lose my data saved in eprom?
Or the data remain saved in eprom?

Thanks in advance.

[ezflyr]

Hi,

I've never seen EEPROM spelled so many (incorrect) ways in one thread!

John

[orazio]

oh!!! maremma bucaiola!!!!

Do you like now, Johnny?

People's forum, excuse me, I'd like to know information about BOOTLOADER IN PIC18 with eeprom and maintaining data in EEPROM when i re-install myapp.hex using bootloader.

Suppose that i install bootloader in a chip PIC18 with eeproom.
Suppose that on power-on, i enter in bootloader section and i install via RS232 myapp.hex. After installation, the PIC reset and start with myapp.hex.
Suppose that myapp.hex save data in eeprom.
If i re-install myapp.hex using bootloader, after installation and PIC reset do i lose my data saved in eeprom?
Or the data remain saved in eeprom?

John, avoids the comments and answer the question, please.

[RF_Developer]

[Ttelmah]

Take a breath.

An EEPROM, is a type of EPROM or PROM.....
All are 'programmable read only memories', but the former is electrically erasable, while the second is erasable without telling you how it is done (typically UV).

Now, ignoring the spelling problems, let's step into the rest of the question.

EEPROM, as a term, is normally used in the PIC to refer to an area of electrically erasable memory, supporting single byte erase/write, with a large write life, designed for storing things like configuration information.
There has become an 'industry standard' in this regard to reserve the term EEPROM, for memory that is _byte_ erasable.

This is 'distinct' from the main 'program memory', which is also technically a type of EEPROM (aargh), called 'Flash', for which the erase cycle, has to be done 'page at a time'. To distinguish this, it is commonly referred to just using the word 'flash', and omitting the EEPROM, to make this page access form obvious. The advantage of this memory form, is it reduces the number of transistors needed, making larger memories at lower costs possible. Only one erase transistor is needed for each whole 'page', instead of having one for every cell.

Now, using the term EEPROM, to specifically refer to byte erasable forms:

The PIC 18F97J60, _does not have EEPROM_ in the chip.
It has flash memory only.

You can add an external EEPROM, like a 2464, and use the supplied drivers, and read/write_ext_eeprom functions to access this.

You cannot write a bootloader 'into' a chip, using an external EEPROM (without adding an external processor to do this) - (slightly 'qualify' this, since on the 100pin devices from this family, a _byte_ accessible external memory could be mapped to be the bootable device using extended micro controller mode, with address shifting, and then with care, could be written to reprogram itself, but this is getting very complex....).

However a bootloader already written into a chip, _can_ be written to program the rest of the chip from the contents of an external EEPROM.
By ensuring the bootloader is not overwritten (this is the 'point' of the bootloader),

Reading and writing the EEPROM are separate functions, so whether you destroy it's contents, are up to you.

Best Wishes

[orazio]

Forget the PIC18F97J60. Now i'm using PIC18F8723 with CCS 4.084.
PIC18F8723 have an eeprom, and in myapp.hex i use it to store configutation data using write_eeprom() function.
In PIC18F8723 i want use eeprom only for storing things like configuration information.

Now i want add to the possibility of being able to download via RS-232 new firmware in my chip, using bootloader concept, but without losing configuration data when i re-install myapp.hex.
Is it possible?
Or when i re-install myapp.hex, via RS-232 using bootloader, i lose configuration data previously saved on eeprom?

This is my question: I want to know if i lose data saved in eeprom after a re-installation firmware by bootloader.
Is it clear the question?

thanks in advance

[Ttelmah]

No.
The bootloader only overwrites what it is told to overwrite. If your file contains data for the EEPROM, then this will be overwritten, but if it doesn't, then it won't.

Best Wishes

[Mike Walne]

[orazio]

Eh.... basta!!!!!

[Mike Walne]

That's out of order.

We're trying to help you.

Mike


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