SPRADO8A March 2025 – May 2026 AM62L
Figure 7-5 includes MMC2 interface configured for SDIO interface connected to an M.2 interface connector. Pullups for DAT0-DAT3 and CMD, series resistor (placed near to the processor clock output pin) and pulldown (placed near to the attached device) for clock input are included. SDIO interface operates on a fixed voltage - 3.3V or 1.8V.
The processor family supports x2 peripheral instances MMC1, MMC2 that can be configured for SDIO interface. The recommendations is to use MMC2 interface for on-board fixed voltage embedded SDIO devices use case such as Wi-Fi or Bluetooth transceivers since MMC2 interface has been tested for SDIO interface on the EVM. MMC1 can be used for SDIO as required. Since the SDIO interface has not been tested on MMC1, customer is expected to check the availability of software support and perform the required performance tests on the custom board design.
A fixed IO supply is used for embedded SDIO interface and simplifies the power architecture. The signals used includes data, command, clock and reset. Connecting SDCD and SDWP signals are optional and can be use case dependent.
There are no specific guidelines about implementation of pulls for embedded SDIO (providing or not providing pulls internal to the interfaced device). Custom board designer implementing an embedded SDIO device is responsible to determine the supported pulls on the SDIO device and apply appropriate external pulls on the custom board design. The processor IOs buffers (for a number of IOs) are off during reset and after reset and are not enabled until the board has booted and the software configures. To prevent floating inputs, the recommendation is to use external pulls on the signals connected to the inputs of attached devices that can float.
For more information, refer to the MMC1/MMC2 - SD/SDIO Interface section of the processor-specific data sheet.
Additionally, see the following FAQ: