LTE Standard Module Series
EG915U_Series_Hardware_Design 50 / 91
4.8. SPI Interface
The module provides one SPI interface that only supports master mode. It has a working voltage of 1.8 V
and a maximum clock frequency of 25 MHz.
Table 22: Pin Definition of SPI Interface
4.9. PSM Interface
*
The module supports power saving mode (PSM). It enters the PSM mode through the following AT
commands when working normally.
⚫
AT+CFUN=4:
Enter airplane mode.
⚫
AT+QSCLK=3:
Enable PSM.
⚫
AT+CFUN=1:
Exit airplane mode.
Pulling the PSM_EINT pin up externally or setting the timer in software will enable the module to exit
PSM.
Pin Name
Pin No.
I/O
Description
Comment
SPI_CLK
26
DO
SPI clock
Just master mode only.
1.8 V power domain.
If unused, keep it open.
SPI_CS
25
DO
SPI chip select
SPI_DIN
88
DI
SPI master mode input
SPI_DOUT
64
DO
SPI master mode output
When the universal 4-wire SPI interface is connected to NOR Flash, it supports basic Flash reading,
writing, erasing and other operations, but you need to perform wear leveling. It does not support file
system and can only be used for storage purpose.
NOTE
