GS6151 Datasheet, PDF (26/77 Pages) Semtech Corporation – Multi-Rate 6G UHD-SDI

4.7 Bypass Mode
In Bypass mode, the GS6151 passes the input data to the outputs, bypassing the
retiming functionality.
There are two bits in the control registers that control the bypass function:
MANUAL_BYPASS and AUTO_BYPASS in the CDR_BYPASS register at address 20_h. The
MANUAL_BYPASS bit is inactive (set to 0) by default. The AUTO_BYPASS bit is active (set
to 1) by default, and places the GS6151 CDR into bypass mode when the PLL is not
locked to a data rate. The bypass function does not affect the trace equalization function
of the device.
Note: If MANUAL_BYPASS is active, it overrides the AUTO_BYPASS bit setting.
4.8 DVB-ASI
The GS6151 has the ability to reclock DVB-ASI signals at 270Mb/s. All relevant settings
and control registers that apply to SD-SDI signals at 270Mb/s are also compatible with
DVB-ASI signals at 270Mb/s.
4.9 Device Power Up
4.9.1 Power on Reset (POR)
The GS6151 features an on-chip power-on-reset that places all registers and internal
state machines into their known, default states when the chip is powered up.
4.10 GPIO Pins Configuration
The GS6151 has two GPIO pins that can each be configured as outputs for various
internal status signals, or as inputs to disable either output-driver via pin control. The
bits GPIO[0:1]_IO_SELECT are used to configure the GPIO pins as outputs (0) or inputs
(1). The signals that are output or input on the GPIO pins are selected by the
GPIO[0:1]_SELECT bits, in conjunction with the GPIO[0:1]_IO_SELECT bits of
GPIO_CONTROL_REG_0 at address 2_h. The signals that can be output on the GPIO pins
are listed in Table 4-5 below and the signals that can be input are listed in Table 4-6.
Table 4-5: GPIO Status Outputs
GPIO[0:1]_SELECT
0000
0001
0010
Parameter
LOS
LOCKED
LBR_HBR
Description
Loss of signal indication - High when there is no detected
signal on the selected DDI input
Phase lock indication - High when the CDR has
phase-locked to a valid input signal
Low bit-rate/High bit-rate - High when the part is locked to
the SD data rate; low for all other data rates and in bypass.
GS6151
Final Data Sheet
PDS-060389
Rev.4
August 2015
www.semtech.com
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