LVDSTester is an automatic test equipment intended for video signal path verification during the post-production Automatic Test Procedure (ATP) in systems featuring LVDS output.
LVDSTester connects using a customized cable to the LVDS output on the equipment under test (EUT) and into a USB port on the system running the ATP routine. LVDSTester analyzes the video frames output to the LVDS port and signals their validity to the ATP system via the USB. LVDSTester emulates a standard USB HID keyboard, hence no custom driver is required for ATP equipment running operating systems with native support for USB HID interface.
Additionally, LVDSTester provides an HDMI connector with DVI signalling which enables monitoring of the LVDS video on a standard HDMI/DVI monitor.
Automatic Go/No-Go LVDS Output Testing
Direct interface to CompuLab’s SBC-fitPC2i, SB-iAM, SB-iTC and other SB-xxx board series LVDS output
Direct interface to Kontron’s JILI (JUMPtec Intelligent LVDS Interface) and EPI LVDS
Single / Dual Channel LVDS Support
Supported resolutions: VGA up to UXGA, custom.
LVDS monitoring output (DVI/HDMI) - single-channel mode only
Plug-n-Play USB HID output (keyboard emulation)
Stand-alone 4-Key USB Keyboard Operation
LVDS-to-DVI (LVDS-to-HDMI) Converter Operation
Click here to download the latest revision of the LVDSTester User's Manual.
Examples of Use
Testing functionality of an LVDS port has never been so easy - ATP software sends test patterns and reads back virtual keyboard's scan codes reporting video frames validity. Visual pass validation is also available (LED) if no automatic process is required.
Here's an example for a PCI Express video card being tested with LVDSTester.
In another example a tiny PC system running self-test, examines its own video output with LVDSTester without intervention of the operator.
LVDSTester detects numerous problems in digital video signal path. Imagine a system being tested, which provides LVDS video output out of a native parallel RGB TTL interface. In such a system, parallel RGB is first converted to LVDS using a LVDS serializer. LVDSTester will verify digital video port functionality in both parallel RGB and LVDS subsystems.
ATP Software Information
No USB driver is required - the LVDSTester is recognized as a Plug-N-Play USB keyboard by HID-enabled operating systems. On the first valid frame the USB interface will transmit 'p'. On the first invalid frame it will transmit 'x'. If 'x' received while sending series of only valid frames to the tested equipment, that means there is a hardware problem in the system under test.
ATP software should enable maximum color resolution up to 24 bpp in order to enable all pixel bits, otherwise pattern recognition will not work.
In DOS 6.22 SEA.EXE program may be used to display test frames. Press * within SEA.EXE to choose screen native resolution and color depth.
Use sample pattern (for 800x600 resolution) or create your own. Any pattern in which each following pixel in the line is the inversion of the previous one will do.
ATP software should not apply any color correction schemes to the output.
ATP software should set the required video mode.
LVDSTester consists of four main blocks:
LVDS Deserializer. Converts the LVDS serialized video data received from the LVDS input, to a 24-bit parallel video data bus which is convenient for further analyzing.
TMDS Serializer. Converts 24-bit parallel video data to serialized stream compatible with DVI/HDMI standard for visual monitoring on digital displays.
Video Data Analyzer. Analyzes the video data, performs video pattern recognition line after line and changes the "VALID" output on frame-by-frame basis according to predefined criteria.
USB Keyboard Emulator. Reports frame validity to the production test equipment.
Valid Test Patterns
The video frame will be accepted by LVDSTester as valid if each line in it consists of alternating pixels, when each following pixel in 24-bit representation is an inversion of the preceding one. For example, the frame consisting of the pixels 000000 and FFFFFF arranged in a checkerboard pattern, will be accepted as valid one. Click here to download the example of this pattern for 800x600 output resolution.
There are endless variances of possible valid frames - in each frame lines may differ one from another, the important thing is alternating inverted pixels in each line.
LVDSTester issues a PASS ('p' character from the emulated USB keyboard) or FAIL ('x' character) output each time the series of valid frames are intercepted with an invalid frame or vise versa. The character is transmitted only once after the first valid or invalid frame in the series. The character will not be repeated after consecutive frames while there is no change in frame validity.
1. LVDSTester PCB
2. USB A-type to Mini-USB cable
3. LVDS signal cable (single ended)
Price and Lead Times
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