第4章_CC2530射频通信之TinyOS组件编程(2).pptx

第4章 CC2530射频通信之TinyOS组件编程(2);Objectives RF Core Frame Format Modulaltion Format Transmit Mode Receive Mode RF State Interrupts RF registers Radio Stack in TinyOS ;CC2530 Radio Stack;RF Core;Frame Format  ;Modulaltion Format  ;Modulaltion Format  ;Tx Control Frame transmission is started by the following actions: · The STXON command strobe – The SAMPLED_CCA signal is not updated. · The STXONCCA command strobe, provided that the CCA signal is high. – Aborts ongoing transmission/reception and forces a TX calibration followed by transmission. – The SAMPLED_CCA signal is updated.  ;Tx Control Frame transmission is aborted by the following command actions: · The SRXON command strobe – Aborts ongoing transmission and forces an RX calibration · The SRFOFF command strobe – Aborts ongoing transmission/reception and forces the FSM to the IDLE state. · The STXON command strobe – Aborts ongoing transmission and forces an RX calibration  ;TX State Timing Transmission of preamble begins 192 ms after the STXON or STXONCCA command strobe. This is referred to as TX turnaround time in [1]. There is an equal delay when returning to receive mode.  ;TX FIFO Access The TX FIFO can hold 128 bytes and only one frame at a time. The frame can be buffered before or after the TX command strobe is executed, as long as it does not generate TX underflow  ;TX FIFO Access There are two ways to write to the TXFIFO. · Write to the RFD register. · Frame buffering always begins at the start of the TX FIFO memory. By enabling the FRMCTRL1.IGNORE_TX_UNDERF bit, it is possible to write directly into the RAM area in the radio memory, which holds the TXFIFO. Note that it is recommended to use the RFD for writing data to the TXFIFO. ;TX FIFO Access The number of bytes in the TX FIFO is stored in the TXFIFOCNT register. The TX FIFO can be emptied manually with the SFLUSHTX command strobe. TX underflow occurs if the FIFO is emptied during transmission.;The TXFIFO and RXFIFO may be accessed