IWR6843AOP: Number of SPI lines

Hello Holger,

    For the SPI operation you would need at least 4 Lines, CLK, MOSI, MISO and CS(Chip select).  There are timing relationship between CS rising and falling edge to SPI clock rising/falling edges. That must be adhered to as shown in the "Standard Serial Peripheral Interface" section of the datasheet. MOSI and MISO lines are needed for the bi-directional communication between the Host and Slave device.

However, if you want to reuse the the Host interface protocol used by the mmWave studio, SPI interface would use additional line Host_Interrupt. This is mainly due to, host has the SPI will have primary control and mmWave device would be secondary device, and host has the control over SPI clock, and for communicating information asynchronously whenever MMIC wants to communicate the information to the host, then it uses out of band interrupt "Host_intr" signal and gets the attention of the Host and its requests for the information through SPI interface. 

If the customer develops their own SPI protocol then only 4 lines are needed. 

Thanks and regards,

CHETHAN KUMAR Y.B.

Hello Holger,

    CS cannot be removed, Toggling of CS w.r.t SPI clock rising/falling edges are essential for the SPI block to work. Hence it cannot removed even for the single slave device, It needs to toggle as recommended timing parameter of the datasheet. 

Thanks and regards,

CHETHAN KUMAR Y.B.