I am working on the new port for Z80180 (banked code). As you know Z80 has NMI interrupt. I am not sure how can I use this type of interrupt with FreeRTOS? I must service this interrupt and can not block it!

Can you look at the Z80 demo available from the FreeRTOS site? Or is it too different?

There is no NMI example in the FreeRTOS distribution. Generaly I would like to use this interrupt the same way like standard INT, but it looks that critical sections will not work correctly with NMI. Because of that I can not post any message using xQueueSendFromISR(...) function. How to solve this problem?

It depends how you want to use the NMI. If it does not interfere with the scheduler data structures then it can be used to interrupt the scheduler with no problem.

I don't know the Z80 - can the other interrupts be prioritised to get the same effect you want.