AR# 73330

LogiCORE IP MIPI D-PHY v4.1 (rev.5) - MIPI D-PHY TX INIT_DONE is not asserted when the IP is generated with 1500 Mbps line-rate configuration

Description

The MIPI D-PHY Controller requires a 200 MHz free running clock (core_clk). This clock is used as input to generate core internal clocks.

A MIPI D-PHY TX user using internal clock sources (for example the PS output clock or MMCM) to feed a 200 MHz core_clk might see that INIT_DONE is not asserted on some of their boards.

INIT_DONE is not asserted when the IP core is generated with the line-rate configuration set to 1500 Mbps, even though IP cores with the line-rate configuration set to 1449 Mbps or 1501 Mbps are working correctly.

Solution

A MIPI D-PHY TX IP with 1500 Mbps line-rate configuration generates an internal clock module with non-optimal PLL divider/multiplier settings.

This causes the output clock to have a poor peak-to-peak jitter and phase-error performance.

If you are using a MIPI D-PHY TX IP with 1500 Mbps line-rate configuration, and are using internal clock sources (for example PS output clock or MMCM) to feed a 200 MHz core_clk then you might see INIT_DONE not asserting on some boards.

This issue can occur on MIPI D-PHY TX IP generated from Vivado 2019.2 (or previous versions) with 1500 Mbps line-rate configuration.

This issue will be fixed in Vivado 2020.1.

Vivado 2019.2 Users can download the MIPI D-PHY patch from (Xilinx Answer 73316) to fix this issue. 

This patch optimizes internal MMCM divider/multiplier settings to improve internal clock peak-to-peak jitter and phase-error performance.

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
54550 LogiCORE IP MIPI D-PHY - Release Notes and Known Issues for the Vivado 2015.3 tool and later versions N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
73316 LogiCORE IP MIPI D-PHY v4.1 (Rev. 5) - Patch Updates for the MIPI D-PHY LogiCORE IP v4.1 (Rev. 5) N/A N/A
AR# 73330
Date 02/07/2020
Status Active
Type General Article
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IP