GS3140 Datasheet, PDF (19/40 Pages) Semtech Corporation – Multi-Rate Adaptive 3G SDI Equalizer

4.10 Device Reset
The GS3140 includes a reset function accessible via the device's host interface, which
reverts all internal logic and register values to default.
The device can be reset with a single write of AD_h to the RESET_CONTROL bits of
RESET_REG_0 register, which will assert and de-assert the device reset within the
duration of the GSPI write access Data Word.
The device can be placed and held in reset by writing AA_h to the RESET_CONTROL bits
of RESET_REG_0 register. Subsequent writes of DD_h to the RESET_CONTROL bits will
de-assert device reset.
The current state of user-initiated device reset can be read from the RESET_CONTROL
bits of RESET_REG_0 register.
While in reset, host interface accesses to any other register will not be functional and all
logic and configuration registers will be in reset state. While in reset serial digital
differential output behaviour is undefined.
The digital logic and registers within the device will exit the reset state 40μs after device
reset is de-asserted.
Note: RESET_REG_0 register writes do not support Auto-Increment mode.
4.11 Gennum Serial Peripheral Interface (GSPI)
The Gennum Serial Peripheral Interface (GSPI) is comprised of a serial data input signal
(SDIN pin), serial data output signal (SDOUT pin), an active-low chip select (CS pin) and
a burst clock (SCLK pin).
The GS3140 is a slave device, so the SCLK, SDIN and CS signals must be sourced by the
application host processor.
All read and write access to the device is initiated and terminated by the application
host processor.
4.11.1 CS Pin
The Chip Select pin (CS) is an active-low signal provided by the host processor to the
GS3140.
The high-to-low transition of this pin marks the start of serial communication to the
GS3140.
The low-to-high transition of this pin marks the end of serial communication to the
GS3140.
There is an option for each device to use a separate unique chip select signal from the
host processor or for up to 32 devices to be connected to a single chip select when
making use of the Unit Address feature.
Only those devices whose Unit Address matches the UNIT ADDRESS in the GSPI
Command Word will respond to communication from the host processor (unless the
B’CAST ALL bit in the GSPI Command Word is set to 1).
GS3140
Final Data Sheet
PDS-060939
Rev.1
May 2015
www.semtech.com
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