Users Manual

RF1276D27 Long Distance Transceiver module V4.0
- 13 - 2016-6-12
Caution:1. When RF1276D27is installed, make sure the antenna is far away from device to enhance the performance.
2. RF1276D27 should have the same common ground with MCU or terminal. Otherwise it may cause the
module irregular working.
3. When RF1276D27 works normal, DO NOT touch the module and antenna.
Figure 7: Connection between Module and Device (TTL/UART port)
10. Constructing Network (one point to multi-point):
RF1276D27 is a semi-duplex module, which can be communicated by point to point or one point to
multi-point. In the second mode, user needs to set one master module, while the others are slave modules.
Every module must only have one unique ID. The coordination of communication is controlled by the
master module, which sends data or commands including ID information. All slave modules can receive
the data packets, and compare the ID with itself. If they are matched, the module will deal with the data
packets. Otherwise, it will discard them. In order to avoid interfering each other, only one module can be
in transmitting state when the network is working. RF1276D27 can set many different frequencies so that
many networks can work in the same place and at the same time.
User should pay attention to the following questions based on the complex transfers in the air and some
inherency characteristics of wireless communication:
1）Latency of wireless communication
The wireless terminal keeps receiving data packets after waiting for a while to ensure no data any
more.There should be tens to hundreds mil-seconds latency from transfer to receiver (the exact
latencydepended on UART rate, air rate and the size of data package). In addition, it also needconsume
some time to transmit from module to terminal, but the delay time is permanentin the same condition.
2）Data flux control
Although there is a buffer zone with 256 bytes in the wireless module, when the UART rate is higher than
the air rate, there must be a problem about the data flux. It may cause to lose some data because the data
overflow from the buffer. Under this condition, it must be ensured that the average UART rate should