MICRF405 Datasheet, PDF (14/46 Pages) Micrel Semiconductor – 290MHz-980MHz ISM Band ASK / FSK Transmitter

Micrel
MICRF405
Preamble
1-4 bytes
SyncID
1-4 bytes
Frame length
1 byte
Payload
2/2/1-253/254/255 bytes
Table 7. Virtual Wire Packet Structure Overview.
CRC
2/1/0 bytes
SyncID_Len
0
0
1
1
SynchID_Len
0
1
0
1
Start of transmitted packet. Leftmost byte transmitted first
Preamble
SyncIDO
Frame length
Preamble
SyncIDO
SyncID1
Frame length
Preamble
SyncIDO
SyncID1
SyncID2
Frame length
Preamble
SyncIDO
SyncID1
SyncID2
SyncID3
Table 8. Virtual Wire Packet Structure, SyncID field.
Frame length
Packet Engine Overview:
• Preamble generated by packet engine: 1-4 bytes equal 10101010. Length set by Pream_Len[1:0]
• SyncID field added by packet engine: 1-4 bytes of user defined content. Length set by SyncID_Len[1:0].
Content set in registers SyncID0, SyncID1, SyncID2 and SyncID3, address 28-25.
• The frame length is entered by user for each packet. Specify the length of the payload and CRC fields in
bytes, ranging from 2 to (255 ÷ # CRC bytes). # CRC bytes can be 0 to 2.
• For each payload byte, wait for falling edge of RDY before writing the byte into the DATA register.
• The optional CRC field ends the packet. Its length is programmable 0, 1 or 2 bytes by the Sel_CRC[1:0].
April 2006
14
M9999-041906
[phone]