4 byte page write command for EEPROM 24C08

[conkhicon]

EEPROM 24C08 help?

I see EEPROM 24C08 datasheet have a page write command.
Each page write command is 8/16 word data. I only want to write 4 byte for page write option. Who had been you wrote the same as?

 

[manu]

Re: EEPROM 24C08 help?

You can't bit write, only 8/16 bits writing.
Regards,

 

[conkhicon]

Re: EEPROM 24C08 help?

Thank!
But I don'n want bit write.
Can I only write four bytes in eight/sisteen sequence in page write mode? 12 bytes remain is not write anh will be not change?

 

[XNOX_Rambo]

Re: EEPROM 24C08 help?

In the datasheet for AT24C08 it says "partial page writes allowed" which means
that you can write fewer bytes in page write mode, if you issue a STOP condition
after your last byte.

/Rambo

 

[manu]

Re: EEPROM 24C08 help?

Thank!
But I don'n want bit write.
Can I only write four bytes in eight/sisteen sequence in page write mode? 12 bytes remain is not write anh will be not change?

Yes, we talk about the same thing, but... My language is bad, sorry

It's not sure at all that you can write only 4 bits; think if you send your data : You must send 8 bits data, imposed by manufacturer, you would send '0000xxxx' or 'xxxx0000' to EEPROM, '0000' will write as 0 bits : Last data would be cleared.

Why not preliminary read the byte contain by the block adress which you want write with your 4 bits data, check if this block is blank, is yes, you send '0000xxxx' or 'xxxx0000' data, if no, you save the block in the RAM of your µC, you add this MSB or LSB one with your 4 bits MSB or LSB data, and you send the result to your EEPROM by I²C bus.

It's the method that i always use with 14 bits Flash write on PICs.

I hope that can help you

Regards,

Manu

 

[Taro]

EEPROM 24C08 help?

I agree with XNOX_Rambo,
You can write it as you comment, but in continous writing mode (PAGE WRITE) wrote data must not exceed 16 byte.

and you must issue a STOP condition after your last byte.

 

[conkhicon]

Re: EEPROM 24C08 help?

In the datasheet for AT24C08 it says "partial page writes allowed" which means
that you can write fewer bytes in page write mode, if you issue a STOP condition
after your last byte.

/Rambo

I hope so.
But I think that "partial" mean that all of 8/16 bytes counting in totally EEPROM (8K in 24C08 ot 16K in 24C16)

 

[XNOX_Rambo]

Re: EEPROM 24C08 help?

No, it means that you kan write a partial 8-byte or 16-byte page, depending
on the EEPROM type.

If you want to write e.g. 32 bytes at one time (in a 16-byte page EEPROM) you
need to perform 2 complete "page writes".

If you want to write 38 bytes you need to perform 2 complete page writes and
one partial, which is stopped after 6 bytes by issuing a STOP condition.

/Rambo

 

[conkhicon]

Re: EEPROM 24C08 help?

thank XNOX_Rambo!
And this is a final question:
Did you try the methode any times in actuality ?

 

[XNOX_Rambo]

Re: EEPROM 24C08 help?

No - this is only my own interpretation of the datasheet.

The datasheets are seldom crystal clear on each and every subject, so I
understand your reason for asking.
I checked a couple of datasheets and not all of them say "partial page writes
allowed" - this quote comes from the Atmel datasheet - so to be absolutely sure,
you need to test your EEPROM.

Generally speaking, if you are going to build something that will be produced in
great numbers, you should also test that your second source EEPROMs behave
in the same manner.

/Rambo

 

[conkhicon]

Re: EEPROM 24C08 help?

Thank very much. I will be meet in another topics