RISC OS Open
A fast and easily customised operating system for ARM devices
ROOL
Home | News | Downloads | Bugs | Bounties | Forum | Documents | Photos | Contact us
Account

VIDC control list

Programmer's Reference Manuals
» VIDC List
» VIDC control list

VIDC control list

Control lists are used with type 3 VIDC lists as a way of specifying extra settings. Each entry in the list is a pair of words, with the first word being the control index and the second word being the value. Under RISC OS 5, the defined values are:

Control index Description Values
1 LCD mode 0 => disable, 1 => enable
2 LCD dual panel mode 0 => disable, 1 => enable
3 LCD offset register 0 0-255
4 LCD offset register 1 0-255
5 High res mode 0 => disable, 1 => enable
6 DAC control setting 0 => disable, 1 => enable (default)
7 RGB pedestals bit 0 = R, bit 1 = G, bit 2 = B
8 External register value 0-255
9 H clock select ?
10 R clock frequency ?
11 DPMS State 0-3
12 obsolete (was Interlace setting)
13 Output format 0 => analogue, 1 => digital
14 Extra bytes 0+
15 NColour value see below
16 ModeFlags value see below

Notes

Control list items 3 and 4 are specified in a format suitable for writing to the VIDC20 LCD offset registers. Items 1, 5, 7 and 8 control various bits of the VIDC20 “external register” register. Similarly, items 2, 9 and 10 are only of interested to VIDC20 systems.

Control item 11 can be ignored by video drivers, as the appropriate DPMS state will be specified by the kernel on calls to GraphicsV 4.

Control item 13 is only relevant for Chrontel-based hardware.

Control item 14 specifies how many bytes there are between the end of one row and the start of the next. This value does not take into account the implicit skipping of every other row that must occur for interlaced displays; i.e. it’s specified as if a standard progressive framestore is used.

Control items 15 and 16 are used in combination with the Log2BPP value from the VIDC List Type 3 to indicate the pixel format. If left unspecified in the control list, the NColour and ModeFlags values will take the default values listed in the “Conversions to/from Log2BPP values” section of the Valid Mode Variable Combinations page.

Note that control items 12 and 13 have different meanings under RISC OS Select.

See Valid Mode Variable Combinations for a list of all valid NColour, ModeFlags and Log2BPP values currently understood by the OS.

See also

  • VIDC List
  • VIDC List Type 3
  • Mode Variable Numbers
  • Valid Mode Variable Combinations
Revised on May 6, 2019 14:24:25 by Sprow (202)? (82.153.112.232)
Edit | Back in time (10 revisions) | See changes | History | Views: Print | Source | Linked from: Extended Framebuffer Format Specification, VIDC List Type 3, GraphicsV 18, ScreenModes_ReadInfo 1, GraphicsV 19, Proposed Multiple Display implementation

Search the Wiki

Social

Follow us on and

ROOL Store

Buy RISC OS Open merchandise here, including SD cards for Raspberry Pi and more.

Donate! Why?

Help ROOL make things happen – please consider donating!

RISC OS IPR

RISC OS is an Open Source operating system owned by RISC OS Developments Ltd and licensed primarily under the Apache 2.0 license.

Navigation

  • Home Page
  • All Pages
  • Recently Revised
  • Authors
  • Feeds
Site design © RISC OS Open Limited 2018 except where indicated
The RISC OS Open Instiki theme is based on Insitki's default layout

Valid XHTML 1.0  |  Valid CSS

Instiki 0.19.1(MML+)
This site runs on Rails

Hosted by Arachsys