My next question involves the SPI functionality in Paparazzi. When I look at spi_hw.h, I see the old #include BOARD_CONFIG which leads me to believe that this file is old and has not been kept up to date with the recent changes in Paparazzi. It refers to #defines that either don't exist anymore, or have been moved. Specifically, I'm looking for a way to pull down the SSEL line to start an SPI transaction. The spi.h file does not seem to be much help. How would I do this?