STM32H5 I3C Controller can't receive IBI Payload more than 4 bytes

[Andy Tsai]

Hi,

I am using the nucleo-h563 I3C (Controller mode) to connect to a JEDEC I3C standard DDR5 PMIC chip. The CCC & private communication is doing well by the STM32H563. But when I trying the IBI transfer, I found the IBI request from the PMIC which the payload is 6 bytes including the MDB byte. For JEDEC standard, it might even contain a PEC byte which is a CRC-8 checksum as the 7th byte. Since the STM32H563 can accept max. 4 bytes(limited by I3C_IBIDR) only, The H563 will interrupt the IBI transfer at the 4th data byte. Refer to the following image:

Because the IBI transfer is interrupted and not completed, the PMIC will repeatedly issue the IBI request as follow:

Is there any method can make the MCU accept the whole payloads ? Any kind of help is appreciated.

[Foued_KH · Accepted solution]

Hello @Andy Tsai , 

No way to accept more than 4 bytes.

When the peripheral acts as controller, the I3C_IBIDR register is used to receive the IBI data payload. Consequently, the IBI request from the target must not exceed a 4-byte data payload. If there is more information to be exchanged in the context of this in-band interrupt, the controller software must issue a private read.

Foued

[Andy Tsai]

Hi @Foued_KH ,

Thank you for your confirmation, I saw the Fig.664 also. Now I try to make the IBIDEN=0, but the IBI is still can be awared by the main procedure and issue a private read to cheat the device. I can image that before the private read, the device will repeatedly generate the IBI request.

[Foued_KH]

I think you should disable the reception of the notification (IBI event) from the PMIC .

Foued