Rev1.0 | 41/50
CMT2300A
Preamble
Sync Word
Node ID
Data
CRC
Payload/CRC
1
2
3
4
5
Manchester/Whiten/FEC(7,4)
Manchester
Data-Only CRC
Figure 22. Fixed length packet
Rx processing
In the packet mode, the output data from the demodulator will be transferred to the packet handler for decoding, and then filled in the
FIFO. The packet handler provides a variety of decoding mechanisms and options to determine the validity of the data. These can
reduce the work load of the MCU. The typical package mode control sequence for the MCU is:
1.
Configures GPIO using the CUS_IO_SEL register.
2.
Setup the interrupts usingCUS_INT1_CTL, CUS_INT2_CTL and CUS_INT_EN registers.
3.
Send the go_rx command.
4.
Reads the RX FIFO according to the relevant interrupts.
5.
Sends the go_sleep/go_stby/go_rfs command to stop the receiving and save the power.
6.
Clears the packet interrupts using CUS_ INT_CLR1 and CUS_INT_CLR2 registers.
Tx processing
In the packet mode, MCU can fill the data in the FIFO in advance in the STBY and TFS state, or fill them in the FIFO while the chip
sends the data, or use the combination of the above two methods. The typical Txpacket mode control sequence for the MCU is:
1.
Configures GPIO usingthe CUS_IO_SEL register
2.
Sends go_stby/go_tfs command when the data is filled in FIFO in advance.
3.
Sends go_tx command.
4.
Writes the data into FIFO according to the relevant interrupt status.
5.
Sends go_sleep/go_stby/go_rfs command to save power.
CMT2300A has rich configurable hardware resources of FIFO, packet and their interrupts, which makes it compatible with most of
the similar RF products in the market. For more details please refer to the interface of RFPDK and
“AN143-CMT2300A FIFO and
Data Packet Usage
Guideline”.