Product Manual

MeiGProductManualofSLM750Module
SLM750ModuleHardwareDesign Page 57, total 84 pages
between the module and the SD card. The bypass capacitors C1~C6 are reserved with no
mounting by default. All resistors and bypass capacitors should be placed close to the module.
 In order to offer good ESD protection, it is recommended to add TVS on SD card pins.
 It is important to route the SDIO signal traces with total grounding. The impedance of SDIO
data trace is 50 ohm (±10%).
 Keep SDIO signals far away from other sensitive circuits/signals such as RF circuits, analog
signals, etc., as well as noisy signals such as clock signals, DCDC signals, etc.
 It is recommended to keep the trace length difference between CLK and DATA/CMD less than
1mm and the total routing length less than 50mm. The total trace length inside the module is
27mm, so the exterior total trace length should be less than 23mm.
 Make sure the adjacent trace spacing is two times of the trace width and the bus capacitance is
less than 15pF.
3.19 USB_BOOT Interface
SLM750 supports USB_BOOT functionality. The customer can pull the USB_BOOT to
VDD_EXT (1.8 V) before the module is turned on, and the module will enter mandatory download
mode when boots. In this mode, the module can be upgraded through the USB interface.
Table 22: Pin Definition of USB_BOOT Interface
Pin name Pin number I/O Description Note
USB_BOOT 115 DI Emergency
download mode
control, high
level active
1.8V power supply domain, it is
recommended to reserve test
points; suspend when no used.