Hardware Guide

4 Circuit Design

peripherals with high real-time requirements, please do not share I

C with other

peripherals.

4.4.4 SD card

The module supports a set of SD card interfaces that support SD 3.0 protocol. The

following figure shows the SD reference circuit design.

Figure 16. SD reference circuit design

PCB Design

SD circuit design must meet EMC standards and ESD requirements, and at the same time,

EMS capability must be improved to ensure that the SD card can work stably. The

following principles must be strictly followed in the design:

 If the cabling length of signal lines is equal to or less than 50 mm. It is recommended

to place the SD card connector as close to the SD signal pins of the module as possible

because the internal cabling length of the module is 40 mm. If the cabling length is

equal to or less than 10 mm, the cabling length difference of the clock signal line and

data signal line should be controlled equal to or less than 1 mm.