MT312
Contents
1
1.1
1.2
1.3
1.4
1.4.1.1
1.4.1.2
1.4.2
1.4.3
1.4.3.1
1.4.3.2
1.4.4
1.4.5
1.4.6
1.5
1.5.2
1.6
1.7
1.7.1
1.7.2
Contents
Functional Overview ............................................................................................. 10
Introduction ........................................................................................................................................ 10
Analogue-to-Digital Converter ............................................................................................................ 10
QPSK Demodulator ............................................................................................................................ 10
Forward Error Correction .................................................................................................................. 11
Viterbi Error Count Measurement ................................................................................................ 11
Viterbi Error Count Coarse Indication .......................................................................................... 12
The Frame Alignment Block ........................................................................................................ 12
The De-interleaver Block ............................................................................................................. 13
DVB ............................................................................................................................................. 13
DSS ............................................................................................................................................. 13
The Reed Solomon Decoder Block ............................................................................................. 14
The Energy Dispersal (De-Scrambler) Block, DVB only .............................................................. 14
Output Stage ............................................................................................................................... 15
Control ................................................................................................................................................ 15
Symbol Rate and Code Rate Search Mode ................................................................................ 16
Direct Conversion Application ............................................................................................................ 16
DiSEqC™ Transmit and Receive Messages ..................................................................................... 17
DiSEqC™ Transmitting Messages .............................................................................................. 17
DiSEqC™ Receiving Messages .................................................................................................. 17
2
2.1
MT312 Software Control ....................................................................................... 18
MT312 Register Map Overview .......................................................................................................... 18
3
3.1
3.2
3.3
3.4
3.5
3.5.1
3.5.2
3.5.3
3.6
3.6.1
MT312 Initialisation ............................................................................................... 19
The Configuration Register (127) ....................................................................................................... 19
Power Supplies ................................................................................................................................... 19
Initialisation Sequence ....................................................................................................................... 20
Spectral Inversion .............................................................................................................................. 21
MT312 Initialisation Read/Write Registers ......................................................................................... 21
Reset. Register 21 (R/W) ........................................................................................................... 21
MT312 Configuration. Register 127 (R/W) ................................................................................. 22
System Clock Frequency. Register 34 (R/W) ............................................................................. 23
MT312 Initialisation Read Register .................................................................................................... 23
Identification. Register 126 (R) ................................................................................................... 23
4
4.1
4.2
4.3
4.4
4.4.1
4.4.2
4.4.3
4.5
4.5.1
4.5.2
Tuner Control ......................................................................................................... 24
Simple Channel Change Sequence ................................................................................................... 24
Channel Change Sequence with a new Symbol Rate ....................................................................... 24
Channel Change Sequence with Search Mode ................................................................................. 24
Tuner Control Read/Write Registers .................................................................................................. 25
General Purpose Port Control. Register 20 (R/W) ..................................................................... 25
FR LIM: Frequency Limit. Register 37 (R/W) ............................................................................. 26
FR OFF: Frequency Offset. Register 38 (R/W) .......................................................................... 27
Tuner Control Read Registers ........................................................................................................... 27
Measured LNB Frequency Error. Registers 7 - 8 (R) ........................................................................ 27
Frequency Error 1 and 2. Registers 111 - 115 (R) ............................................................................ 28
4
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