14 WINC SPI Protocol

The WINC main interface is SPI. The WINC device employs a protocol to allow exchange of formatted binary messages between the WINC firmware and the host MCU application. The WINC protocol uses raw bytes exchanged on the SPI bus to form high level structures like requests and callbacks.

The WINC SPI protocol consists of three layers:

  • Layer 1 – The WINC SPI Client protocol, which allows the host MCU application to perform register/memory read and write operation in the ATWINC15x0 device using raw SPI data exchange.
  • Layer 2 – The host MCU application uses the register and memory read and write capabilities to exchange the host interface frames with the WINC firmware. It also provides asynchronous callback from the WINC firmware to the host MCU through interrupts and the host interface RX frames. For more information on this layer, refer to Section 15 “Host Interface (HIF) Protocol”.
  • Layer 3 – Allows the host MCU application to exchange high level messages (for example, Wi-Fi scan, socket connection or TCP data received) with the WINC firmware to employ in the host MCU application logic.
Figure 14-1. WINC SPI Protocol Layers