NTAG5 not working in I2C fast mode

[Stabilo23]

Dear support team,

I am currently working with a NTAG 5 devloppement kit and a STM32 NUCLEO board.
Everything is working fine when the I2C master is communicating at 100khz.
But when I switch to 400 khz, my I2C driver directly detects an "acknowledge failure" error.

Is there something specific to configure in the NTAG 5 chip to work at 400khz ?
I will do further analysis, but I was just wondering if this was a known issue on your side.

Thanks.

[kkla203]

hi, i'm working on ntag5 and stm32 nuvleo board as well to establish i2c, but all i receive are nack bits, is it because I'm accessing a locked register? all i'm doing is this

ret = HAL_I2C_Master_Transmit(&hi2c1, ntag5_addr, (uint8_t *)dataBuffer, 12, 100);

if (ret!= HAL_OK)

{

HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, 1);

}

if (ret == HAL_OK){

HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_5);

HAL_Delay(200);

}

HAL_Delay(1000);

[Kan_Li]

Hi @Stabilo23 ,

NTAG 5 supports 400 kHz in I2C fast mode, but I have not heard any known issue from this. How about the connection between the NTAG 5 devloppement kit and your STM32 NUCLEO board? Did the timing meet the requirement in "10.2 Dynamic characteristics" of the data sheet?

Have a great day,
Kan

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!
- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

[Stabilo23 · Accepted solution]

Hi Kan,

Thank you for your answer. The issue was due to the pull up resistors not enabled on the NTAG board. By luck it was working at 100KHz with pull up resistors disabled.

With pull up resistors enabled, everything is working fine at 400KHz.

[Kan_Li]

Hi @Stabilo23 ,

Great to know this issue has been solved ! Thanks for the update!

Have a great day,
Kan

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!
- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------