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FS32K1xx series MCU SPI continuous transmit mode

Question asked by Xiaoyu Wang on Apr 24, 2018
Latest reply on Apr 26, 2018 by Daniel Martynek

In my ADAS project, I am using FS32K144 to control the ECU communication with vehicle and implement ECU power management. MCU will forward vehicle information(which come from CAN or LIN bus) to SoC, it can also forward ECU information to vehicle. For communication between MCU and SoC, I reserved UART and SPI.

Due to UART baud rate constraint, I have to 2 ways:

1. Use UART to transmit command, and transmit data via SPI . 

      With this way, due to communication will be frequency, maybe UART will be the chock point of communication. Another problem with this way is that, the communication protocol will be complex.

2. Only use SPI

      With this way, I want to drive SPI interface work continuously. But if I drive next communication in transmit data complete interrupt, it will wast much MCU resource.

I review S32K reference manual, there are some part mentioned continuous transmit mode, I am interested about it. But I didn't really understand it.  For this topic, can anyone answer me following questions:

1. How to implement SPI continuous transmit mode and how is it work progress?

2. Will it waste CPU resources?(will it enter interrupt frequency?)

Another part which I was interested in is about the SPI host request. I was always thinking about host role(due to I didn't really understand clearly). For this question, I need support on following question:

1. What is the host and how to implement the host role?

2. What is the host work progress during SPI communication?