8.5.2 Design Layout Recommendations

No particular layout recommendation about the wireless module is provided in this chapter. All modules have their own recommendations described in their data sheet or application note. Refer to the appropriate document.

When designing the SDIO interface for the wireless solution, consider the following recommendations:

  • Apply impedance control of 50 Ohms on the clock and data interfaces.
  • Match the SDIO signal lengths to within 20 mils. Affected PIOs in the above example are PA2 to PA4, PA11 to PA13.
  • Place the clock line (PA13) at least three times the trace width away from other signals for noise immunity.
  • Place data signals at least two times the trace width away from any other data trace.
  • Design data signals at least two times the trace width away from any copper plane.
Figure 8-7. SDIO Wireless Interface Layout Example