Quectel EG91 Series User Manual

LTE Standard Module Series
EG91 Series Hardware Design
EG91_Series_Hardware_Design 51 / 106
3.13. SPI Interface
SPI interface of EG91 series module acts as the master only. It provides a duplex, synchronous and serial
communication link with the peripheral devices. It is dedicated to one-to-one connection, without chip
selection. Its operation voltage is 1.8V with clock rates up to 50MHz.
The following table shows the pin definition of SPI interface.
Table 15: Pin Definition of SPI Interface
Pin Name Pin No. I/O Description Comment
SPI_CLK 26 DO Clock signal of SPI interface 1.8V power domain
SPI_MOSI 27 DO
Master output slave input of SPI
interface
1.8V power domain
SPI_MISO 28 DI
Master input slave output of SPI
interface
1.8V power domain
The following figure shows a reference design of SPI interface with peripherals.
Figure 25: Reference Circuit of SPI Interface with Peripherals
The module provides 1.8V SPI interface. A level translator should be used between the module and the
host if customer’s application is equipped with a 3.3V processor or device interface.
NOTE

Quectel EG91 Series Specifications

General

Brand	Quectel
Model	EG91 Series
Category	Control Unit
Language	English