About NFC Time (using ST25DV16K EEPROM)

[GOODTHINK]

Hello, I have a question for NFC R/W mode (read/write EEPROM with ST25DV16K)

tag : ST25DV16K - Nfc tag 4 click

reader : STM32 + X-Nucleo_Nfc08a1

1. When writing data to the ST25DV16K board via RF, how long does it take to read the data via I2C?

2. It takes 5ms to write 1Block data with RF as shown in DataSheet. Is the writing time 5ms? Or does it mean that I should read it after 5ms of writing?

Thank you!!!

[JL. Lebon]

Hello, 

5ms is the time taken to program one block of the EEPROM memory. When you write a memory block from RF, the programing is done between the RF request (command sent by the NFC reader) and the RF response (answer sent by the ST25DV16K). The ST25DV16K sends the response after the end of EEPROM writing, which is 5ms after receiving the write request.

The MCU can read the data from I2C as soon as the ST25V16K has sent the RF response. During the RF request/writing/response process, the ST25DV16K can't be accessed from I2C.

The ST25DV16K also provides an interrupt to inform the MCU that a write in EEPROM has been executed (RF_WRITE interrupt). This can help synchronizing I2C read after an RF write.

Best regards.