www.ti.com

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

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.

10

Submit Documentation Feedback