GS3470 datasheet(87/169 Pages) SEMTECH

87 / 169 page

GS3470

Final Data Sheet

Rev.8

PDS-060500

September 2017

87 of 169

Semtech

www.semtech.com

4.20.1 CS Pin

The Chip Select pin (CS) is an active-low signal provided by the host processor to the

GS3470.

The HIGH-to-LOW transition of this pin marks the start of serial communication to the

GS3470.

The LOW-to-HIGH transition of this pin marks the end of serial communication to the

GS3470.

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).

4.20.2 SDIN Pin

The SDIN pin is the GSPI serial data input pin of the GS3470.

The 16-bit Command and Data Words from the host processor or from the SDOUT pin of

other devices are shifted into the device on the rising edge of SCLK when the CS pin is

low.

4.20.3 SDOUT Pin

The SDOUT pin is the GSPI serial data output of the GS3470.

All data transfers out of the GS3470 to the host processor or to the SDIN pin of other

connected devices occur from this pin.

By default at power up or after system reset, the SDOUT pin provides a non-clocked path

directly from the SDIN pin, regardless of the CS pin state, except during the GSPI Data

Word portion for read operations to the device. This allows multiple devices to be

connected in Loop-Through configuration.

For read operations, the SDOUT pin is used to output data read from an internal

Configuration and Status Register (CSR) when CS is LOW. Data is shifted out of the device

on the falling edge of SCLK, so that it can be read by the host processor or other

downstream connected device on the subsequent SCLK rising edge.

GS3470 Datasheet(PDF) 87 Page - Semtech Corporation