RF64 Datasheet, PDF (45/76 Pages) List of Unclassifed Manufacturers – ADVANCED COMMUNICATIONS & SENSING

RF64
ADVANCED COMMUNICATIONS & SENSING
If the transmitter is switched off (for example due to entering another chip mode) during transmission it will stop
immediately, even if there is still unsent data.
Figure 39 illustrates Tx processing with a 16 byte FIFO depth and Tx_start_irq_0=0. Please note that in this
example the packet length is equal to FIFO size, but this does not need to be the case, the uC can use the FIFO
interrupts anytime during Tx to manage FIFO contents and write additional bytes.
Start condition
(Cf. Tx_start_irq_0)
Fifofull
/Fifoempty
Tx_done
15 b15
b14
b13
b12
b11
b10
FIFO
b9
b8
b7
b6
b5
b4
b3
b2
b1
0
b0
Data Tx
(from SR)
from
SPI Data
XXX
b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 b10 b11 b12 b13 b14 b15 XXX
Figure 39: Tx processing in Buffered Mode (FIFO size = 16, Tx_start_irq_0=0)
5.4.3. Rx Processing
After entering Rx in Buffered mode, the chip requires the uC to retrieve the received data from the FIFO. The FIFO
will actually start being filled with received bytes either; when a Sync word has been detected (in this case only the
bytes following the Sync word are filled into the FIFO) or when the Fifo_fill bit is asserted by the user - depending
on the state of bit, IRQParam_Fifo_fill_method.
In Buffered mode, the packet length is not limited i.e. as long as Fifo_fill is set, the received bytes are shifted into
the FIFO.
The uC software must therefore manage the transfer of the FIFO contents by interrupt and ensure reception of the
correct number of bytes. (In this mode, even if the remote transmitter has stopped, the demodulator will output
random bits from noise)
When the FIFO is full, Fifofull IRQ source is asserted to alert the uC, that at that time, the FIFO can still be unfilled
without data loss. If the FIFO is not unfilled, once the SR is also full (i.e. 8 bits periods later) Fifo_overrun_clr is
asserted and SR‟s content is lost.
Figure 40 illustrates an Rx processing with a 16 bytes FIFO size and Fifo_fill_method=0. Please note that in the
illustrative example of section 5.4.6, the uC does not retrieve any byte from the FIFO through SPI Data, causing
overrun.
Page 45 of 76
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