ST25DV64KC Write Block with Vcc ON

[Pengy]

I'm trying to write a block ( 4 bytes) of normal memory from RF (via an Android) using command 0x21.

I can do this with Vcc OFF, no problems.

I also need to write to the Mailbox (command 0xAA), but to do this I have to have Vcc ON (obviously the I2C can't read that message without Vcc).

The Write Block (0x21) returns 2 bytes, 0x01 0x0F, which is "unknown error".

What do I need to do/set to allow the RF Write Block to work with Vcc ON?

Many thanks in advance, gurus!

[JL. Lebon · Accepted solution]

Hello, 

There is nothing to do to allow RF to write blocks when Vcc is ON.
RF should be able to write blocks independently of Vcc presence.

You said that you are using the mailbox. The error 01 0F is most probably returned by the ST25DV because you have activated the mailbox. Actually, when mailbox is activated (bit MB_EN=1 in the register MB_CTRL), the EEPROM memory (user memory only) can't be written anymore (read only).
You can see that in the datasheet, on page 26 in chapter 5.1 Fast transfer mode (FTM). There is a "Caution" note that explains this.
Before sending the RF Write Block command, try to deactivate the mailbox temporarily by writing MB_EN=0 with the RF Write Dynamic Configuration command and the Write Block should work.

Best regards.

[Pengy]

Many thanks! I missed that caution note in the middle of a 200 page document!

I'm very grateful, thank you!

:thumbs_up: