SPI and UART are among the most commonly-used protocols in today’s embedded applications. Often, there is a requirement to expand a single SPI master to several UART interfaces or to have a bridge between SPI and UART interfaces due to peripheral limitations in processors interacting with each other. The SPI-to-UART Expander provides a cost-effective solution for communicating from a host processor’s SPI bus to multiple UART devices. This reference design acts as a SPI port expander, multiplexing and demultiplexing read/write data through the SPI slave to multiple UARTs using iCE40™ FPGAs.
The SPI-to-UART Expander interfaces the host processor/microcontroller’s SPI master to a number of UARTs through a SPI slave.