Si1000/1/2/3/4/5
23.6.10. Receive Header Check
The header check is designed to support 1–4 bytes and broadcast headers. The header length needs to
be set in register 33h, hdlen[2:0]. The headers to be checked need to be set in register 32h, hdch[3:0]. For
instance, there can be four bytes of header in the packet structure but only one byte of the header is set to
be checked (i.e., header 3). For the headers that are set to be checked, the expected value of the header
should be programmed in chhd[31:0] in Registers 3F–42. The individual bits within the selected bytes to be
checked can be enabled or disabled with the header enables, hden[31:0] in Registers 43–46. For example,
if you want to check all bits in header 3 then hden[31:24] should be set to FF but if only the last 4 bits are
desired to be checked then it should be set to 00001111 (0F). Broadcast headers can also be programmed
by setting bcen[3:0] in Register 32h. For broadcast header check the value may be either “FFh” or the
value stored in the Check Header register. A logic equivalent of the header check for Header 3 is shown in
Figure 23.19. A similar logic check will be done for Header 2, Header 1, and Header 0 if enabled.
Example for Header 3
rxhd[31:24]
BIT
Equivalence
comparison
WISE
hden[31:24]
=
BIT
WISE
chhd[31:24]
header3_ok
bcen[3]
Equivalence
comparison
FFh
=
hdch[3]
rxhd[31:24]
Figure 23.19. Header
23.6.11. TX Retransmission and Auto TX
The transceiver is capable of automatically retransmitting the last packet loaded in the TX FIFO. Automatic
retransmission is set by entering the TX state with the txon bit without reloading the TX FIFO. This feature
is useful for beacon transmission or when retransmission is required due to the absence of a valid
acknowledgement. Only packets that fit completely in the TX FIFO can be automatically retransmitted.
An automatic transmission function is available, allowing the radio to automatically start or stop a transmis-
sion depending on the amount of data in the TX FIFO.
When autotx is set in “Register 08. Operating & Function Control 2", the transceiver will automatically enter
the TX state when the TX FIFO almost full threshold is exceeded. Packets will be transmitted according to
the configured packet length. To stop transmitting, clear the packet sent or TX FIFO almost empty inter-
rupts must be cleared by reading register.
268
Rev. 1.0
SILICON [ SILICON ]
