Product Info

LTE Module Series
EG91 Hardware Design
EG91_Hardware_Design 51 / 93
3.13. SPI Interface
SPI interface of EG91acts asthe master only. It provides a duplex, synchronous and serial communication
link with the peripheral devices. It isdedicated to one-to-one connection, withoutchip select.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 areference 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 applicationis equipped with a 3.3V processoror device interface.
3.14. Network Status Indication
The module provides one network indication pin: NETLIGHT. The pin is used to drive a network status
indication LED.
NOTE