XE8000EV108 Semtech, XE8000EV108 Datasheet - Page 90

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

Specifications of XE8000EV108

• Contents: Fully Assembled Evaluation Board
• For Use With/related Products: XE88LC06AMI026
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

The start pattern can not be less than 8 bits since no bits can be set as “don’t care”.
14.8.3
The interface can receive coded or uncoded messages. The coding/decoding function is enabled/disabled using
the bit RfifEnCod (1 = enable) in the register RegRfifCmd2.
The PCM code type is selected using the RfifPCM[2:0] control word in the register RegRfifCmd2. The selection
control bits are given in Table 14-12.
PCM Codes
If the decoder detects invalid code sequences and the selected start detection mode is not the “protocol “ mode
(RfifEnStart[1:0] ≠ 01, see Table 14-13), the decoder output generates an equivalent number of random data bits.
If the decoder is disabled (RfifEnCod = 0), the meaning of the RfifPCM[2:0] changes: if the NRZ coding is
selected, the input bit stream is sampled at the selected bit rate. If the Manchester or Miller coding is selected, the
input stream is sampled at twice the data rate. This allows the decoding of the bit stream by software.
14.8.4
The decoder output data are serially shifted in a shift register (see Figure 14-1). The bit RfifRxBusy = 1 in
RegRfifRxSta indicates that new data are shifted in.
When 8 new bits are present in the shift register, the byte is loaded in the FIFO. The FIFO has a depth of 4. The bit
RfifRxReady = 1 in RegRfifRxSta indicates that at least 1 byte is present in the FIFO. The software can read the
data in the FIFO in RegRfifRx. When the bit RfifRxFifoFull is 1, the FIFO is full and data should be read by the
software before the next byte is received. If not, data will be lost and the bit RfifRxFifoOverrun is set to 1. Writing
a 1 to this bit will clear the bit and the FIFO contents. The detection of a new start sequence will also clear the
RfifRxFifoOverrun bit and the FIFO contents.
The first bit that is received can be found in the position RfifRx[0], the second bit in the position RfifRx[1] and so
on.
© Semtech 2006
RfifPCM[2:0]
RfifRxSPat=10011111
decoded data
NRZ - Mark
PCM decoding
Reception FIFO
Figure 14-6. Pattern start detection in NRZ-Mark for RfifRxSPat[7:0]=10011111
Level
000
1
Mark
NRZ
001
1
1
Table 14-14: PCM code selection
1
Space
010
0
1
start sequence
0
14-10
Level
011
0
0
0
first bit in FIFO
Bi-Phase
1
Mark
100
1
1
0
Space
101
XE8806A/XE8807A
0
1
1
Miller
11X
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