Datasheet

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OPERATION MODE AND CLOCK TRANSITION SIGNAL OUT
Operation Mode
DIR9001
SLES198 – DECEMBER 2006
The DIR9001 has the following three operation modes.
These modes are selected by the connection of the CKSEL pin.
• PLL MODE: For demodulating a biphase input signal; always outputs PLL source clock
• XTI MODE: For clock generator; always outputs XTI source clock
• AUTO MODE: Automatic clock source selection; output source depends on ERROR pin.
Notes about operation mode selection:
• Normally, the PLL mode: CKSEL = L is selected to decode a biphase input signal.
• The XTI mode is a mode that supplies the XTI source clock to peripheral devices (A/D converters, etc);
therefore, recovered clock and decoded data is not output.
• When the XTI source is not used, an XTI source is not required. In this case, clocks are not output in the XTI
mode.
• At the time of XTI mode selection, biphase decode function continues to operate. Therefore, the biphase
input status (ERROR) and the result of the sampling frequency calculator (a required XTI source for
operation), are always monitored. That is, the following output pins: ERROR, BFRAME, FSOUT[1:0], CLKST,
AUDIO and EMPH are always enabled.
The details of these three modes are given in Table 2 .
Table 2. Operation Mode and Clock Source
OPERATION CKSEL PIN ERROR DOUT DATA AUDIO FSOUT BFRAME COUT
SCKO, BCKO, LRCKO
MODE SETTING PIN EMPH [1:0] UOUT
CLOCK SOURCE
STATUS
H PLL (VCO) free-running MUTE (Low) LOW HL LOW LOW
clock
(1)
PLL L
L PLL recovered clock Decoded data OUT OUT OUT OUT
H XTI clock MUTE (Low) LOW HL LOW LOW
XTI H
L XTI clock MUTE (Low) OUT OUT OUT LOW
H XTI clock MUTE (Low) LOW HL LOW LOW
Connected to
AUTO
ERROR pin
L PLL recovered clock Decoded data OUT OUT OUT OUT
(1) The VCO free-running frequency is not a constant frequency, because the VCO oscillation frequency is dependent on supply voltage,
temperature, and process variations.
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