參數(shù)資料
型號: MT312
廠商: ZARLINK SEMICONDUCTOR INC
元件分類: 消費家電
英文描述: Satellite Channel Decoder
中文描述: SPECIALTY CONSUMER CIRCUIT, PQFP80
封裝: MQFP-80
文件頁數(shù): 20/90頁
文件大小: 318K
代理商: MT312
MT312
Initialisation
20
3.3 Initialisation Sequence
MT312 will be in the power save mode after a
hardware reset. The
fi
rst command to be written
must be to the CONFIGURATION register at address
127. After loading this register, wait 150μs before
writing to the RESET register. During this wait, the
tuner can programmed to the required channel
frequency via the General Purpose Port (register
20). If the AGC slope control bit of AGC CTRL(39) or
the AGC REF(41) are to be changed, it is best to
write to these registers after writing to the RESET
register. This will allow the front-end AGC loop to
settle while the other registers are being written.
Next write 128 to the RESET register (21) to reset
the MT312 state machine and all parameter registers
to the default settings. It is then necessary to change
the default setting of register 49 to 50 (decimal).
If necessary, other default parameters may need to
be changed. These may include:
Slope of AGC control signal - see register (39)
ACG CTRL[B0] AGC SL bit
AGC Reference value - see register (41) AGC
REF
Relative phase of IQ spectrum - see register
(25) VIT MODE[B6]
LNB frequency search range, default is ±6MHz
- see register (37) FR LIM
For low Baud rates only, set fast frequency
acquisition mode - see register (26) set QPSK
CTRL[B2] = 1
To invert MOCLK or BKERR output signals - see
register (96) OP CTRL
After this, the LNB controls are de
fi
ned, in register
(22) DISEQC MODE.
The signal parameters should then be written to the
MT312. The symbol rate (registers 23 & 25 SYM
RATE) may be speci
fi
ed within ±2% of the required
value, absolute precision is not required to achieve
successful lock and tracking. If the symbol rate is
unknown, a search mode is available.
Selecting the correct bit of register (25) VIT MODE, if
known, programs the convolutional code rate. If the
code rate is unknown, some or all of the bits of VIT
MODE may be set to force the MT312 to search for
the code rate.
Finally, the MT312 is given a GO command, register
(27) GO =1, to release the state machine and to start
the signal acquisition sequence. This is summarised
as an example in the following
fl
ow diagram.
Enable MT312 : Program CONFIG
Reg 127 = 140 (8Chex)
Program tuner via GPP in 'pass through mode'
open port with Reg 20 = 64 (40hex)
send TUNER DATA via I2C bus (5 bytes).
close port with Reg 20 = 0
Reset MT312 to default register settings
Reg21 = 128 (80hex)
Set SYS_CLK = 2*Xtal*PLL_RATIO
Set DISEQQC_RATIO (if required)
Set AGC_SL (if required)
Initialise register: reg 49 = 50 (32hex);
DiSEqC mode
eg Horizontal with 22kHz on:
Reg 22 = 65 (41hex)
Signal input - Symbol rate
eg 27.5 MBaud:
Reg 23 = 27 (1Bhex) DEFAULT state
Reg 24 = 128 (80hex) DEFAULT state
Viterbi code rate
eg V_IQ swap not set, CR = 3/4:
Reg 25 = 4 (4hex)
QPSK control
eg DVB : roll-off = 0.35:
Reg 26 = 0 DEFAULT state
GO
Release reset state to start signal capture
Reg 27 = 1
Figure 15 - Initialisation sequence in DVB mode
相關PDF資料
PDF描述
MT312T-Y 2x4mm Rectangular LED Lamps
MT3371BN Wide Dynamic Range DTMF Receiver
MT3371BS Wide Dynamic Range DTMF Receiver
MT3371BNR Wide Dynamic Range DTMF Receiver
MT3371BSR1 Wide Dynamic Range DTMF Receiver
相關代理商/技術參數(shù)
參數(shù)描述
MT3-1203SI 制造商:VOLGEN 制造商全稱:VOLGEN 功能描述:3 WATT DC/DC CONVERTER, SIINGLE & MULTIIPLE OUTPUTS
MT3-1205SI 制造商:VOLGEN 制造商全稱:VOLGEN 功能描述:3 WATT DC/DC CONVERTER, SIINGLE & MULTIIPLE OUTPUTS
MT3-1212SI 制造商:VOLGEN 制造商全稱:VOLGEN 功能描述:3 WATT DC/DC CONVERTER, SIINGLE & MULTIIPLE OUTPUTS
MT3-1212WI 制造商:VOLGEN 制造商全稱:VOLGEN 功能描述:3 WATT DC/DC CONVERTER, SIINGLE & MULTIIPLE OUTPUTS
MT3-1215WI 制造商:VOLGEN 制造商全稱:VOLGEN 功能描述:3 WATT DC/DC CONVERTER, SIINGLE & MULTIIPLE OUTPUTS