Skip to main content
Associate II
December 2, 2025
Question

Clarifications for VD55G1 MIPI ULPM / CHANNELSTATS_ROI_REDUCE_FACTOR

  • December 2, 2025
  • 2 replies
  • 498 views

ULPM for the MIPI CSI interface of VD55G1 is not clearly described.

Errata (es0643) section "QVGA at 480 fps" say that we should put MIPI in ULPM. Why does this affect timing?

WRITE_REG8 STREAM_STATICS_OIF_ULPM 'h01 # MIPI in ULPM

Is this a MIPI setting (continuous/discontinuous)? 

Additionally, a register write is referred to that is not documented anywhere in the datasheet or integration guide.

WRITE_REG8 CHANNEL_STATS_ROI_REDUCE_FACTOR 'h10 # 16 lines removed to the stats ROI

What is this register? The address is not even known.

2 replies

ST Employee
December 2, 2025

Hello,

1. ULPM itself is a low-power state and not directly a “continuous” or “discontinuous” data mode. However, enabling ULPM means the interface can enter low power during idle times, which is typical in discontinuous or burst transmission scenarios.

2.There are a total of 16 ROIs for an image, and the ROI reduction factor is usually found in the STREAM_STATICS register group, typically between addresses 0x0302 and 0x0312.

 

 

Regards

Chad

pleAuthor
Associate II
December 2, 2025

Hi Chad, thank you for the reply!

I assume that means the STATS_REDUCE_ROI_FACTOR register refers to OIF_ISL_CTRL, a 5:0 R/W register at 0x0310 "CSI data type selection for status lines"? There is essentially no documentation in um3224 clarifying the bits in this register.

ST Employee
December 3, 2025

Hello,

Some documents require an NDA to be signed before they can be shared. If your company has signed the NDA, you can ask your PM or Sales representative to request the register maps for you.