PORTENTA X8 How to share data STM32 <=> NXP?

Official Hardware Portenta Family Portenta X8
1

Hello,

How to share data between ST32 and NXP ? In SPI ?

image

there is no shared memory ?

Thank you

2

What do you mean by "shared memory"?
Another MCU cannot look into memory of another MCU. Shared Memory is only there in the same MCU, not between MCUs (PCs).

You need a communication interface between both MCUs (and SW running on both sides). This can be SPI.

When I see this drawing: "yes, there is a SPI interface, as "ECSPI3". And with a SPI protocol you can let "talk" both MCUs to each other (and transfer data, but just indirectly via sending and receiving data packets).

Write a SPI Master and Slave, on of each on both ends, implement a protocol ("SPI commands") and transfer the data.
There is not another way to "look directly into memory" from one MCU into another MCUs memory (it could be also the same memory address on both sides - how MCU would know what is "external"? And another MCU is not a memory device).

Shared memory is just on a single chip "multi-core MCU" but not on a "multi-MCU system".
Your PC cannot look into my PC's memory. You need a network protocol between both parties in order to transfer data (memory content).

3

Hi,
Thank you for your answer

I noticed that the NXP had a M4 cortex co-processor with shared memory. The STM32H7 also had a CORTEX M4 co-processor with shared memory

I thought that there would have been shared memory (external) between the NXP and the STM32H to dialogue quickly.

4

Sure, shared memory between the cores inside the same chip. But no shared memory between two MCUs. You need an external communication interface (SPI, I2C, UART, SAI/I2S, SWPMI, ETH, MDIO - but STM is just a slave).
For a real shared memory between both MCUs - you would need an external (Dual-Port) RAM and the Memory Controller on both sides (way too complicated but the fastest).

I guess, they have the SPI connected between both. So, write a SPI Slave on one side, a SPI Master on the other side and send SPI packets (with your SPI protocol).

5

Thank you

6

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