HDMI Intel® FPGA IP User Guide

ID 683798
Date 3/03/2023

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6.1.20. Avalon Memory-Mapped Demultiplexer

Avalon memory-mapped demultiplexer demultiplexes a single Avalon slave interface to four Avalon master for HDMI register, Clocked Video to AXI4-stream, EDID RAM and HDCP (for future use) based on the respective address offset. The slave on the Avalon memory-mapped demultiplexer is operating at word addressing.

Master Address Offset Size


EDID RAM 0x0000 16 For HDMI DDC channel for accessing external sink SCDC and EDID and for link training function
Clocked Video to AXI4-stream 0x0100 256 Control and status register on Clocked Video to AXI4-stream
EDID RAM access 0x0200 1 Indicates host processor is accessing or updating EDID RAM. All other read and write operations to the EDID stop. Upon de-assertion of this signal, RX hotplug signal toggles to trigger the external HDMI source to read the EDID.
HDCP register 0x0300 256 Reserved for HDCP registers
HDMI register 0x0400 256 Control and status register on HDMI core

The output data to from the Avalon memory-mapped demultiplexer (AVMM demultiplexer) to HDMI register, Clocked Video to AXI4-stream bridge and HDCP are 32 bits. The write and read operation are channeled through to the respective master according to the address offset. However, EDID RAM has only 8 bits interface due to limitation that the same interface is used by the I2C slave for DDC. Hence, 1 single write operation from the AVMM demultiplexer slave interface of 32-bits data translates into 4 continuous write operation to the EDID RAM with the address increased accordingly on the EDID RAM.