Hi, I'm reading TinyOS source code. I am confused about codes of FIFOP pin and FIFO pin written in /tinyos-2.1.1/tos/chips/cc2420/receive/CC2420ReceiveP.nc file.
1. CC2420ReceiveP.nc says " The FIFOP pin here is high when there are 0 bytes in the RXFIFO and goes low as soon as there are bytes in the RXFIFO. The pin is inverted from what the datasheet says, and its threshold is 127." However, the datasheet says FIFO pin should be high (or low if the pin is inverted) "when there is one or more data bytes in the RXIFO." My question is does that conflict if FIFOP pin takes care of FIFO pin's job? If FIFO pin is high, what does it mean? 2. According to datasheet, FIFOP pin is high (low in tinyOS) "when the number of unread bytes in the RXFIFO exceeds the threshold programmed into IOCFG0.FIFOP_THR". How do I know whether unread bytes in RXFIFO exceeds threshold? Where do we compare them? 3. Does TinyOS-2.1.1 take care of RXFIFO overflow? For example, it is likely that at receive state, CC2420 can receive data packets from the channel as well as send RXFIFO's data to AVR through SPI. At this point, if RXFIFO overflows (receiving data's speed much faster than SPI's speed), what should I do? Thanks. Jingyao
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