SPRUIW8 November 2020
The F28002x MCU features the Fast Serial Interface (FSI) communications peripheral. The FSI enables robust high-speed communications and is intended to increase the amount of information transmitted while reducing the cost to communicate over an isolation barrier. The FSI signals TXCLK, TXD0, TXD1, RXCLK, RXD0, and RXD1 are available on J11. This header is set up in such a way that adding jumpers on the pins will connect the TX to RX channels for external loopback and evaluation. Additionally, there are two GND signals on the connector that can be used for a wrapped-pair connection to an external board with FSI. The GPIOs connected to this header are also routed to the BoosterPack connectors through 0Ω resistors. As the FSI can toggle at up to 100 MHz rates, the longer traces to the BoosterPack headers can create unintentional noise on the signal due to reflection. Eliminating these extended traces by removing the in-circuit resistors will help to limit any noise or reflections.
The LAUNCHXL-F280025C does not include any on-board isolation devices for the FSI signals. If interested in evaluating the FSI peripheral with isolation devices, or differential drivers/receivers, please see the TMDSFSIADAPEVM plug on board.