SWRA779 September   2023 CC3300 , CC3301

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Main Features
    1. 2.1 Dual Host Interface
    2. 2.2 Shared Host Interface
    3. 2.3 Autonomous Mode
    4. 2.4 Host Interrupt
      1. 2.4.1 Out-of-Band Interrupt
      2. 2.4.2 In-Band Interrupt
  6. 3Interfaces
    1. 3.1 Introduction
    2. 3.2 SDIO Interface
      1. 3.2.1 SDIO Overview
      2. 3.2.2 SDIO Flow Control
    3. 3.3 SPI Interface
      1. 3.3.1 SPI Overview
      2. 3.3.2 SPI Configuration
      3. 3.3.3 SPI Flow Control
    4. 3.4 Uart Interface
      1. 3.4.1 UART Overview
      2. 3.4.2 UART Configuration
      3. 3.4.3 UART Flow Control
    5. 3.5 Pin Count Options
  7. 4Host Communication
    1. 4.1 Protocol Overview
    2. 4.2 SDIO Wrapper
    3. 4.3 SPI Wrapper
  8. 5Boot Flow
    1. 5.1 SDIO
    2. 5.2 SPI

4.1 Protocol Overview

Regardless of what hardware interface is used, the traffic is carried over a well-defined protocol. Each hardware interface uses a different wrapper that implements the specific hardware protocol but the actual payload is the same. The protocol details are listed in this section for completeness but do not require any porting efforts from the developer/integrator.

The protocol consists of several command options:

  • Generic command format. In this command, no host_rx is involved
    GUID-20230522-SS0I-3WLW-KVSZ-NXPWWVQT8WRX-low.png Figure 4-1 Generic Command
  • send() or sendto() command format. The device returns a status response indicating the success of the command
    GUID-20230522-SS0I-PGBR-NQM4-BWBMPXZG1CX2-low.png Figure 4-2 Send or Sendto Command
  • recv() or recvfrom() command format, in which the response contains data packet or not
    GUID-20230522-SS0I-JRMF-KR0J-TG2TMJTQQR3Q-low.png Figure 4-3 Recv or Recvfrom Command
  • read_status sequence format, where the host requests the device to provide an immediate status
    GUID-20230522-SS0I-CSTK-CQ84-TZPS9CMLHDLS-low.png Figure 4-4 Read_status Command
  • cnys sequence format, where the host requests the device to provide a single, highest priority, packet
    GUID-20230522-SS0I-C1XH-TVM8-C4ZNX4N02KJS-low.png Figure 4-5 Cnys Command

Table 4-1 describes the different command fields.

Table 4-1 Protocol Structure
Field Description
SYNC Constant pattern which is used to synchronize the boundary of a command or response
Opcode Identifies the command or response (depends on direction of the traffic)
Length Length of everything that follows this field
Descriptors Depending on the opcode/command, descriptors may follow that provide further information. For example, for a send() operation, the descriptor identifies the socket, flags and length of the actual payload. It also requires a Tx status response field
Payload Anything else that the command needs
CNYS Constant pattern which triggers the device to respond with received data or event