I am learning the implementation of USB on MC9S08JM. I have a few questions:
- What is meant by a USB transaction? For example in a Control Transfer, does it mean the completion of each phase (Setup phase, Data phase, Handshake phase), or the completion of all 3 phases?
- The TOKDNE interrupt is triggered after each phase, or after the 3 phases has completed?
- If TOKDNE interrupt is triggered after each phase - that means for the entire Control Transfer, 3 interrupts will be triggered. How does the CPU handle each interrupt?