XE8000EV108 Semtech, XE8000EV108 Datasheet - Page 97

EVAL BOARD FOR XE8806/XE8807

XE8000EV108

Manufacturer Part Number
XE8000EV108
Description
EVAL BOARD FOR XE8806/XE8807
Manufacturer
Semtech
Type
MCUr
Datasheets

Specifications of XE8000EV108

Contents
Fully Assembled Evaluation Board
For Use With/related Products
XE88LC06AMI026
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
lost by lack of space in the FIFO (overrun error which sets the flag RfifRxFifoOverrun) or because the start
sequence of the next message is detected which resets the reception FIFO.
When the complete message is received, the start sequence detection interrupt may be enabled again
(RfifRxIrqEn = 001) and the sequence starts all over again.
14.12.1.3 Reception mode using Manchester coding
The protocol of the messages received is Manchester Mark. The start sequence of the message is protocol
violation. The messages are sent at a data rate of 20 kbit/s (40 kbaud/s in Manchester code). The following
paragraphs will show how to set-up the XE1201A, how to set-up the RF interface and how to handle the received
data.
14.12.1.3.1
To set the XE1201A in reception mode, set the pin EN to 1 and the pin RXTX to 1. The bit synchronizer of the
XE1201A is not used since the RF interface automatically synchronizes to the bit rate. This means that the data
registers of the XE1201A can remain in the default settings shown in Table 14-20. However, in order to reduce the
power consumption, the XE1201A bit synchronizer can be switched off by writing the bits A(9:6) = 0101 as shown
in Table 14-22.
14.12.1.3.2
Set-up the RF interface of the microcontroller circuit as a receiver (RfifEnRx = 1 and RfifEnTx = 0).
Assume that the RC clock frequency used in the microcontroller is 2.0 MHz. To select the correct baud rate of 20
kbit/s according to the equation in chapter 14.10 (attention: the baud rate is twice the bit rate in Manchester code),
fine*coarse=2.0e06/(16*40e3)=3.12. We can approximate this at 3, which is close enough (see specification in
Table 14-19). This can be done by setting RfifBRCoarse = 00 and RfifBRFine = 0010.
The external bit synchronization clock is switched off by clearing the bit RfifRxClock = 0.
The decoder is enabled and set to Manchester Mark decoding by setting RfifEnCod = 1 and RfifPCM = 100.
The start detection by protocol violation is enabled by setting RfifEnStart = 01.
The start sequence detection interrupt is enabled by setting RfifRxIrqEn = 001.
The set-up of the interface is summarized in the Table 14-23.
© Semtech 2006
Register
Register A
Register B
Register C
Table 14-22. XE1201A register set-up (see XE1201A datasheet for bit explanation)
XE1201A set-up
RF interface set-up
0
0
0
13
0
0
1
12
RegRfifCmd1
RegRfifCmd2
RegRfifCmd3
Register
Table 14-23. RF interface set-up
0
0
0
11
0
0
1
10
0
0
0
9
14-17
1
0
1
8
0
0
0
7
1
0
0
6
00000010
10100100
00100010
contents
0
0
1
5
1
0
0
4
0
0
0
3
XE8806A/XE8807A
0
0
0
2
0
0
0
1
0
0
0
0
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