A N 6 9 2
Rev 0.4
45
The basic operation of low duty cycle mode is shown in Figure 37. The host MCU periodically wakes up the radio
chip to work in reception mode. If a valid preamble is not detected within the "LDC_CONFIG_AWAKE_TIME_MS"
time, the host MCU forces the receiver to "LDC_State_Sleep State" state and it remains in that mode until the
"LDC_CONFIG_SLEEP_TIME_MS" time elapses. If a valid preamble is detected, signed by
"PREAMBLE_DETECT_PEND" interrupt, the receiver gets into "LDC_State_Wait_Sync_Word" state. If a valid
sync word is not detected within the "LDC_CONFIG_SYNC_TIMEOUT_MS" time, the host MCU forces the
receiver to "LDC_State_Wait_Preamble" state. If a valid sync word is detected and signed by
"SYNC_DETECT_PEND" interrupt, the receiver gets into "LDC_State_Wait_Packet_Rx" state. If the whole packet
is not received within "LDC_CONFIG_PACKET_RX_TIMEOUT_MS" time, the host MCU forces the receiver to
"LDC_State_Wait_Preamble" state. If the packet is received successfully and signed by "PACKET_RX_PEND"
interrupt, the host MCU reads the RX FIFO's content and flashes the appropriate LED(s). After finishing the LED
activity, host MCU starts the reception by vRadio_StartRX( )function. The example code is capable of receiving
three types of packets previously described in the "Reception of a Simple Packet in Packet Handler Mode". The
timeout periods can be configured in the "ldc_config.h" header file in ms unit. Note that the low duty cycle feature is
not implemented internally in the radio chip, but the host MCU controls the internal state of the radio.
Figure 38. Configurable Packet Related Time Intervals in the Host MCU
Summary of Contents for Si4455 Series
Page 8: ...AN692 8 Rev 0 4 Figure 6 Device Configuration Options ...
Page 22: ...AN692 22 Rev 0 4 Figure 21 Supply Current versus Time Diagram from Shutdown to RX State ...
Page 23: ...AN692 Rev 0 4 23 4 4 Radio Chip Waking Up Figure 22 Radio Wake Up Process ...
Page 35: ...AN692 Rev 0 4 35 Figure 32 Transmission Flowchart ...
Page 39: ...AN692 Rev 0 4 39 Figure 33 Reception Flowchart ...
Page 41: ...AN692 Rev 0 4 41 Figure 34 Bidirectional Variable Packet Example Project Flowchart ...
Page 47: ...AN692 Rev 0 4 47 Figure 41 Long Packet Transmission Flowchart ...
Page 48: ...AN692 48 Rev 0 4 Figure 42 Long Packet RX Flowchart ...