Intel® Core™ Ultra Processor

Datasheet, Volume 1 of 2
Supporting Intel® Core™ Ultra Processor for U/H/U-Type4-series Platforms, formerly known as Meteor Lake

ID Date Version Classification
792044 03/05/2024 Public

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Document Table of Contents

Functional Description

GPIO Serial Expander (GSX) uses serial-to-parallel or parallel-to-serial shift register discrete components to increase number of the GPIO pins for system use. It expands in the multiples of 8 for input or output with 8 pins per expander. The total shift register component supported is 8, which can expand the GPIOs by up to 64.

The below figure illustrates a GPIO expansion topology with 16 GPIs and 16 GPOs.

GSX Topology - Example

Coming out of system reset, GSX is in reset with the following behaviors:

  • GSXSRESET# asserted by default. The signal remains asserted until BIOS/SW initialization has been completed and CxCMD.ST set to 1.

  • GSXSLOAD is 0 by default until CxCMD.ST is set to 1.
  • GSXSCLK is not toggling until CxCMD.ST is set to 1.