The TX FIFO is preloaded with data. The data is not being transmitted to the CC2420 as the transmission is taking place, unlike other chips. Because of the preload, it is impossible for the CC2420 to produce a TXFIFO UNDERFLOW. All the data to send is available on the chip when transmit occurs.
Due to the rules of the CSMA and Transmit modules, a new packet cannot be uploaded to the TX FIFO until the previous packet in the TX FIFO was transmitted. This should guarantee that the TX FIFO be empty when the next transmit occurs. If a cancel occurs, a quick SFLUSHTX empties the contents of the TX FIFO. -David -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Liusand Sent: Friday, March 14, 2008 12:45 PM To: tinyos-help@millennium.berkeley.edu Subject: [Tinyos-help] TXFIFO underflow not taken care of in TinyOS 2.0.2? Hi, When I was studying CC2420TransmitP.nc, I noticed that TXFIFO is never flushed and underflow status is never checked. In CC2420RadioM.nc from TinyOS 1.1.15, TXFIFO is flushed in startSend() every time before it is written data to. It might be too conservative in TinyOS 1.1.15, but why overflow is never taken care of in TinyOS 2.0.2? Another related question is, in which situations TXFIFO underflow may happen? Thanks, Sha _______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
