Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 1/24/2025
Public

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5.8.9.2.1. I3C Interface Design Guidelines

The I3C protocol supports dynamic switch between the open-drain, Hi-Z, and push-pull conditions. You must enable the dynamic pull-up port feature in the general-purpose I/O (GPIO) IP to ensure that the I3C functions correctly. The HVIO buffer needs to be configured as no clock. For more information, refer to the General-Purpose I/O User Guide: Agilex™ 5 FPGAs and SoCs.

At a top level, the connection between the HPS and the HVIO is wire only.

The following Verilog code shows the GPIO instantiation for an I3C interface implemented through the FPGA:
gpio i3c0_sda_buffer_t3 (.dout(i3c_sda_in_a), .din(i3c_sda_out), .oe(i3c_sda_oe), .puen(i3c_sda_pullup_en), .pad_io(i3c_sda));

gpio i3c0_scl_buffer_t3 (.dout(i3c_scl_in_a), .din(i3c_scl_out), .oe(i3c_scl_oe), .pad_io(i3c_scl));