DisplayPort Intel® FPGA IP User Guide

ID 683273
Date 1/24/2022
Public

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9.4. btc_dprx_aux_handler

Prototype:

int btc_dprx_aux_handler( 
   BYTE         rx_idx 
   BYTE         cmd,
   unsigned int address, 
   BYTE         length, 
   BYTE         *data)

Thread-safe:

Yes

Available from ISR:

Yes

Include:

< btc_dprx_syslib.h >

Return:

0 = success, 1 = fail

Parameters:

  • rx_idx—Sink instance index (0 - 3)
  • cmd—Command
  • address—Address
  • length—Length (0 - 16)
  • data—Pointer to data being written

Description:

This function processes an AUX channel request issued by the connected DisplayPort source.

cmd and address are the command byte and the address in the original request received, respectively (refer to the VESA DisplayPort Standard for more details). When the request is a write, data must point to the data bytes sent by the source. To support address-only requests, length is the original len byte sent by the source incremented by one. When the request is a read, data is not used and can be NULL.

This function provides all the functionality of the DPCD registers implemented inside the system library, including:

  • DPCD locations read/write support
  • EDID read support
  • Link training execution
  • Forwarding of AUX channel replies back to the source

Example:

btc_dprx_aux_handler(0, pcmd, padd, plen, pwrdata);