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

5.1 SDIO

During initialization to SDIO mode, the data lines are not involved and only the clock and command lines are used. However, the procedure might pause and fail if SDIO DAT0 line is asserted (set to low). This is interpreted as a busy signal and the host defers its transmission until the line is de-asserted. This should not occur from the device side unless there is an external pull down.

The main commands involved in the initialization procedure are:

  • CMD5: this command is used to inquire the voltage range needed by the device

  • CMD3: this command is used to assign a logical address to the device

  • CMD7: this command is used to select the desired device according to the logical address and enable it for data transfer

  • CMD52: this command is used to access common I/O area, function 0. Reads/writes one byte using one command/response pair