Display: Difference between revisions

Revision as of 16:38, 12 November 2017

LCD screen

This is a 720p, 8-bits-per-channel LCD with a resistive touch-sensitive layer suitable for use with fingers as well as a high-precision passive stylus. Multi-touch detection is also possible to a limited degree. The market for small LCDs is largely driven by smartphones, making it prohibitively difficult to source a native landscape display. As a result, the Pyra uses a portrait display, ~~with a dedicated video rotation chip~~ interfacing with the CPU/GPU

Tiler

The tiling and isometric lightweight engine for rotation (TILER) resides in the Memory Subsystem of the OMAP5 and Manages the virtual address, data, and byte-enable to match the requested 0-, 90-, 180-, or 270-degree orientation in a tiled 2D addressing space. Previously there was only an slow (because of Bugs) Driver Available, thus the decision above. Later an Community Member (Zmatt) wrote an new Driver, which performed perfectly.

Video Output

The Pyra has a digital video output supporting HDMI 1.4a, HDCP 1.4, and DVI 1.0 which can be used independently of and at higher resolutions than the built-in LCD. (Confirmation Needed)

It uses a 19-pin Type-D micro connector.

Rotator (Not Used)

MIPI signal rotator by Solomon Systech

In an early design of the Pyra hardware, this chip was specified. It allows software to have direct access to the display in its physical orientation (landscape) instead of its native logical orientation (portrait). As noted above (under 'Tiler') Zmatt delivered a tiler driver that obviated the need for a discrete rotation chip.

Although it's possible to apply rotation in software, or by keeping the GPU powered up, this was designed to make porting games easier and quicker, as well as reducing GPU load. The rotator chip uses image compression internally due to memory constraints. This is lossy, but of sufficiently high quality as to be generally imperceptible. Sample images for comparison available here: [[1]]

However, the tiler is part of the SoC so powered up all of the time anyway while the system is on, and while the driver is running is hidden from the developer and just works. It doesn't use compression, so can provide theoretically improved clarity over the rotation chip too!

@@ Line 8: / Line 8: @@
 === Video Output ===
-The Pyra has an digital video output supporting HDMI 1.4a, HDCP 1.4, and DVI 1.0 which can be used independently of and at higher resolutions than the built-in LCD. '''(Confirmation Needed)'''
+The Pyra has a digital video output supporting HDMI 1.4a, HDCP 1.4, and DVI 1.0 which can be used independently of and at higher resolutions than the built-in LCD. '''(Confirmation Needed)'''
 It uses a 19-pin Type-D micro connector.</onlyinclude>
 ===<strike>Rotator</strike> (Not Used)===
 MIPI signal rotator by [http://www.solomon-systech.com/en/ Solomon Systech]
-This is allows software to have direct access to the display in its physical orientation (landscape) instead of its native logical orientation (portrait). Although not strictly necessary, this makes porting games easier and quicker, as well as reducing GPU load. The rotator chip uses image compression internally due to memory constraints. This is lossy, but of sufficiently high quality as to be generally imperceptible.
+In an early design of the Pyra hardware, this chip was specified.  It allows software to have direct access to the display in its physical orientation (landscape) instead of its native logical orientation (portrait).  As noted above (under 'Tiler') Zmatt delivered a tiler driver that obviated the need for a discrete rotation chip.
+Although it's possible to apply rotation in software, or by keeping the GPU powered up, this was designed to make  porting games easier and quicker, as well as reducing GPU load. The rotator chip uses image compression internally due to memory constraints. This is lossy, but of sufficiently high quality as to be generally imperceptible.
 Sample images for comparison available here:
 [[https://pyra-handheld.com/boards/threads/beautiful-landscapes-are-prettier-than-portraits.74058/page-11#post-1296877]]
+However, the tiler is part of the SoC so powered up all of the time anyway while the system is on, and while the driver is running is hidden from the developer and just works.  It doesn't use compression, so can provide theoretically improved clarity over the rotation chip too!
 See also: [[GPU]]