GS3471 datasheet(92/179 Pages) SEMTECH

92 / 179 page

GS3471

Final Data Sheet Rev.4

PDS-060498

September 2017

92 of 179

Semtech

www.semtech.com

4.22.3.1 GSPI Link Disable Operation

It is possible to disable the direct SDIN to SDOUT (Loop-Through) connection by writing

a value of 1 to the GSPI_LINK_DISABLE bit in REGISTER_0. When disabled, any data

appearing at the SDIN pin will not appear at the SDOUT pin and the SDOUT pin is HIGH.

Note: Disabling the Loop-Through operation is temporarily required when initializing

the Unit Address for up to 32 connected devices.

The time required to enable/disable the Loop-Through operation from assertion of the

parameter tcmd_GSPI_config (4 SCLK cycles).

Figure 4-52: GSPI_LINK_DISABLE Operation

4.22.3.2 GSPI Bus-Through Operation

Using GSPI Bus-Through operation, the GS3471 can share a common PCB trace with

other GSPI devices for SDOUT output.

When configured for Bus-Through operation, by setting

GSPI_BUS_THROUGH_ENABLE bit to 1, the SDOUT pin will be high-impedance when

the CS pin is HIGH.

When the CS pin is LOW, the SDOUT pin will be driven and will follow regular read and

write operation as described in Section 4.22.3.

Multiple chains of GS3471 devices can share a single SDOUT bus connection to host by

configuring the devices for Bus-Through operation. In such configuration, each chain

requires a separate Chip Select (CS).

Table 4-27: GSPI_LINK_DISABLE Bit Operation

Bit State

Description

SDIN pin is looped through to the SDOUT pin

Data appearing at SDIN does not appear at SDOUT, and SDOUT pin is HIGH.

SDIN pin

SDOUT pin

GSPI_LINK

_DISABLE

BUS_THROUGH

CS pin

High-Z

Configuration and

Status Register

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