Introduction
This document describes the Spread Spectrum support for displays on i.MX 8QuadMax and i.MX 8QuadXPlus, specific for LVDS display. It describes the underlying HW function, how to enable it and the intended capability.
The display controller (DC) subsystem on i.MX 8QuadMax and i.MX 8QuadXPlus uses an AVPLL to generate the reference clock for operation of the LVDS PHYs. Enabling Spread Spectrum on the reference clock will result in the PHY interfaces being spread as well. This Spread Spectrum feature is controlled by the SCU firmware and can be enabled or disabled by configuring the board file of the SCU firmware porting kit. (The Spread Spectrum feature is added starting from SCFW porting kit V1.2.2 release which can be download from NXP web site “i.MX Software and Development Tool”.)
The User Guide will include following content:
1. Introduction ............................................................................ 1
2. Configuration of the frequency modulation ......................... 2
3. Support in SCFW Porting Kit ............................................... 4
4. Modulation Characteristics ................................................... 4
5. Enablement Example ............................................................. 5
6. Revision History .................................................................... 7
For more information, please check the attachment "User Guide of Spread Spectrum for i.MX8QM_QXP Display.pdf".
Rev2.0 Update
For SCFW Porting Kit V1.2.5 and later version, please check document "User Guide of Spread Spectrum for i.MX8QM_QXP Display 2.0.pdf" with updated algorithm.
Rev2.1 Update
For SCFW Porting Kit V1.2.10 and later version, please check document "User Guide of Spread Spectrum for i.MX8QM_QXP Display 2.1.pdf" with fspread value selection feature. Users can choose the percentage of frequency spread from following values: 0%, 0.4%, 1.0%, 1.4%, 2.0%.
