Sierra Wireless WISMO218 - Manual (Page 36)

WA_DEV_W218_PTS_002 Rev 005 Page 36 of 109
Product Technical Specification &
Customer Design Guidelines
Figure 5. Example of an SPI to UART2 Interface Conversion Implementation
The following table lists the recommended components to use in implementing the SPI to UART2
interface.
Component Description/Details Manufacturer
U103 SC16IS750IPW NXP Semiconductors
X101 3, 6864MHz 86SMX surface mount crystal (971-3131) Farnell
R104, R105 10K 
R106 1K 
C105 22pF
C106 33pF
C107 100nF
After converting the SPI signal to a UART signal, a UART transceiver circuitry is needed to
communicate this UART signal to DTE.