NB-IoT Module Series
BC66 Hardware Design
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Table 10: Pin Definition of SPI Interface
The module provides a 1.8V SPI interface. A level translator between the module and host should be
used if the application is equipped with a 3.3V processor or device interface. A voltage level translator that
supports SPI data rate is recommended. The following figure shows a reference design.
VCCA
VCCB
OE
A1
A2
A3
A4
GND
B1
B2
B3
B4
VDD_EXT
CS_SPI
SCLK_SPI
MOSI_SPI
0.1uF
0.1uF
CS_SPI
SCLK_SPI
MISO_SPI
MOSI_SPI
VDD
Translator
Module
DTE
MISO_SPI
Figure 20: SPI Interface Reference Circuit with Translator Chip
3.10. USIM Interface
The module provides a USIM interface compliant to ISO/IEC 7816-3, enabling the module to access to an
external 1.8V USIM card.
The external USIM card is powered by an internal regulator in the module and supports 1.8V power
supply.
Pin Name Pin No.
I/O
Description
Comment
SPI_MISO
3
DI
Master input slave output of SPI interface
1.8V power domain
SPI_MOSI
4
DO
Master output slave input of SPI interface
SPI_SCLK
5
DO
Clock signal of SPI interface
SPI_CS
6
DO
Chip select of SPI interface
