MSA Values - 1.0 English - PG422

DisplayPort 2.1 RX Subsystem Product Guide (PG422)

Document ID
PG422
Release Date
2025-11-26
Version
1.0 English
Table 1. MSA Values
Offset Access Type Description
0x500 RO MSA_HRES. The horizontal resolution detected in the Main Stream Attributes.

[15:0] - Represents the number of pixels in a line of video

0x504 RO MSA_HSPOL. Horizontal sync polarity.

[0] - Indicates the polarity of the horizontal sync as requested by the transmitter

0x508 RO MSA_HSWIDTH. Specifies the width of the horizontal sync pulse.

[14:0] - Specifies the width of the horizontal sync in terms of the recovered video clock

0x50C RO MSA_HSTART. This main stream attribute is the number of clock cycles between the leading edge of the horizontal sync and the first cycle of active data.

[15:0] - Number of blanking cycles before active data

0x510 RO MSA_HTOTAL. Tells the receiver core how many video clock cycles occur between leading edges of the horizontal sync pulse.

[15:0] - Total number of video clocks in a line of data

0x514 RO MSA_VHEIGHT. Total number of active video lines in a frame of video.

[15:0] - Vertical resolution of the received video

0x518 RO MSA_VSPOL. Specifies the vertical sync polarity requested by the transmitter.

[0] - A value of 1 in this register indicates an active-High vertical sync. A 0 indicates an active-Low vertical sync.

0x51C RO MSA_VSWIDTH. The transmitter uses this value to specify the width of the vertical sync pulse in lines.

[14:0] - Specifies the number of lines between the leading and trailing edges of the vertical sync pulse.

0x520 RO MSA_VSTART. This main stream attribute specifies the number of lines between the leading edge of the vertical sync pulse and the first line of active data.

[15:0] - Number of blanking lines before the start of active data

0x524 RO

MSA_VTOTAL. Total number of lines between sequential leading edges of the vertical sync pulse.

[15:0] - Total number of lines per video frame is contained in this value

0x528 RO

MSA_MISC0. Contains the value of the MISC0 attribute data.

[7:5] - COLOR_DEPTH: Number of bits per color/component.

[4] - YCbCR_COLOR: Set to 1 (ITU-R BT709-5) or 0 (ITU-R BT601-5).

[3] - DYNAMIC_RANGE: Set to 1 (CEA range) or 0 (VESA range).

[2:1] - COMPONENT_FORMAT:

  • 00 = RGB
  • 01 = YCbCr 4:2:2
  • 10 = YCbCr 4:4:4
  • 11 = Reserved

[0] - CLOCK_MODE:

  • 0 = Asynchronous clock mode
  • 1 = Synchronous clock mode
0x52C RO MSA_MISC1. Contains the value of the MISC1 attribute data.

[7] - Implements the attribute information contained in the DisplayPort MISC1 register. See the VESA DisplayPort Standard (VESA website) section 2.2.4 for more information.

[6] - Implements the attribute information contained in the DisplayPort MISC1 register. See the VESA DisplayPort Standard (VESA website) section 2.2.4 for more information.

[5:3] - RESERVED: Bits are always set to 0

[2:1] - STEREO_VIDEO: Used only when stereo video sources are being transmitted. See the VESA DisplayPort Standard (VESA website) section 2.2.4 for more information.

[0] - INTERLACED_EVEN: 1 indicates that the number of lines per frame is an even number

0x530 RO

MSA_MVID. This attribute value is used to recover the video clock from the link clock. The recovered clock frequency depends on this value as well as the CLOCK_MODE and MSA_NVID registers.

[23:0] - MVID: Value of the clock recovery M value.

0x534 RO

MSA_NVID. This attribute value is used to recover the video clock from the link clock. The recovered clock frequency depends on this value as well as the CLOCK_MODE and MSA_MVID registers.

[23:0] - NVID: Value of the clock recovery N value.

0x538 RO

MSA_VBID. The most recently received VB-ID value is contained in this register.

[7:0] - VBID: See Table 2-3 (pg. 44) in the VESA DisplayPort Standard (VESA website) for more information. The default value is 0x19.

0x540 to 0x578 RO Bit definition is identical to that of the MSA Values registers (0x500 to 0x538), but for MST STREAM 2.
0x580 to 0x5B8 RO Bit definition is identical to that of the MSA Values registers (0x500 to 0x538), but for MST STREAM 3.
0x5C0 to 0x5F8 RO Bit definition is identical to that of the MSA Values registers (0x500 to 0x538), but for MST STREAM 4.
0x1608 RO

VFREQ[23:0] -

When [1:0] of 0x434 is 0x10 (that is, for 128b/132b), The VFREQ field holds the lower 24bits [23:0] of absolute pixel rate in units of Hz within ±1% accuracy.

When [1:0] of 0x434 is 0x01 (for 8b/10b), this field is invalid

[23:0] - [23:0] bits of VFREQ value

0x160C RO

VFREQ[47:24] -

When [1:0] of 0x434 is 0x10 (that is, for 128b/132b), The VFREQ field holds the upper 24bits [47:24] of absolute pixel rate in units of Hz within ±1% accuracy.

When [1:0] of 0x434 is 0x01 (that is, for 8b/10b), this field is invalid

[23:0] - [47:24] bits of VFREQ value

0x1610 RW Same as 0x1608 and 0x160C but for MST STREAM 2.
0x1614
0x1618 RW Same as 0x1608 and 0x160C but for MST STREAM 3.
0x161C
0x1620 RW Same as 0x1608 and 0x160C but for MST STREAM 4.
0x1624
0x1628 RW The AFREQ field carries the rate (in Hz) of the absolute primary audio clock. A DP Source device AFREQ value needs to be set within the ±1% accuracy.

[23:0] - [23:0] bits of AFREQ value.

Only applicable for 128b132b link rates.

0x162C RW The AFREQ field carries the rate (in Hz) of the absolute primary audio clock. A DP Source device AFREQ value needs to be set within the ±1% accuracy.

[23:0] - [47:24] bits of AFREQ value.

Only applicable for 128b132b link rates.