Liquid-crystal display test system and method

• US 5,740,352 A
• Filed: 09/27/1995
• Issued: 04/14/1998
• Est. Priority Date: 09/27/1995
• Status: Expired due to Fees

• Current Assignee: B-Tree Verification Systems, Inc. (BSQUARE Corporation)
• Original Assignee: B-Tree Verification Systems, Inc. (BSQUARE Corporation)
• Inventors: Philipp, Richard L., Murphy-Newman, Richard L., Louden, Michael S.
• Primary Examiner(s): Nguyen, Hoa T.
• Assistant Examiner(s): Elmore, Stephen C.
• Application Number:
  US08/534,603
• Time in Patent Office: 930 Days
• Field of Search: 395/183.16, 395/183.01, 395/183.08, 395/183.13, 348/180, 348/185, 324/770, 324/500, 324/754, 324/755, 324/763, 345/50, 128/661.04
• US Class Current: 714/40
• CPC Class Codes: G01R 31/28 Testing of electronic circuits, e.g. by signal tracer EMC, EMP or similar testing of electronic circuits G01R31/002; testing for short-circuits, discontinuities, leakage or incorrect line connection G01R31/50; checking computers or computer components G06F11/00; checking static stores for correct operation G11C29/00 ; testing receivers or transmitters of transmission systems H04B17/00

Abstract

Methods and apparatus for a non-invasive test tool for testing and monitoring the interactions between an embedded microprocessor and its programs, various input analog and discrete electrical signals, and an LCD output display screen. The test tool uses a physical probe, preferably coupled in a non-invasive manner to the pins of the LCD display screen, and specialized hardware to capture the LCD output of the software-under-test as an event interaction between the microprocessor and various inputs. The captured LCD output is converted to a standard pixel format and stored for testing. The standard pixel format comprises a color and/or intensity value for each pixel position of interest, stored into a data structure. One embodiment uses a conversion which includes adding the time-modulated pixel data of a plurality of frames to generate a single composite frame having a color and/or intensity value for each pixel position of interest.

Claims

1. A test system for non-invasively testing a microcomputer system having one or more input stimulus signals and a display screen, the test system comprising:

a electronic probe which generates digital drive data representative of an electronic signal which drives the display screen;

a signal converter coupled to the electronic probe, which converts the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an optical attribute for at least one pixel of the display screen; and

a frame storage coupled to the signal converter for storing the pixel data, wherein the signal converter samples a plurality of pixel values within each of a plurality of frames of the digital drive data and at least one of the plurality of pixel values sampled from a first one of the plurality of frames is combined with a corresponding one of the plurality of pixel values sampled from a second one of the plurality of frames to generate a combined pixel value, and the combined pixel value is saved in the frame storage.

2. The test system according to claim 1, further wherein the pixel data comprises a value representing a color for at least one pixel of the display screen.

3. The test system according to claim 1, further wherein the pixel data comprises a value representing an intensity for at least one pixel of the display screen.

4. The test system according to claim 1, wherein the signal converter samples the digital drive data at a plurality of points in time in order to derive the pixel data for one combined pixel value.

5. A test system for non-invasively testing a microcomputer system having one or more input stimulus signals and a display screen, the test system comprising:

a electronic probe which generates digital drive data representative of an electronic signal which drives the display screen;

a signal converter coupled to the electronic probe, which converts the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an optical attribute for at least one pixel of the display screen; and

a frame storage coupled to the signal converter for storing the pixel data, wherein the signal converter includes a bit-masked change filter.

6. A test system for non-invasively testing a microcomputer system having one or more input stimulus signals and a display screen, the test system comprising:

a electronic probe which generates digital drive data representative of an electronic signal which drives the display screen;

a signal converter coupled to the electronic probe, which converts the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an optical attribute for at least one pixel of the display screen; and

a frame storage coupled to the signal converter for storing the pixel data, wherein the pixel data is organized in the frame storage as a structure, the structure comprising;

a pointer to an array of scan lines and pixels within scan lines;

the array of scan lines and pixels within scan lines; and

parameters which characterize the data in the array.

7. A test system for non-invasively testing a microcomputer system having one or more input stimulus signals and a display screen, the test system comprising:

a electronic probe which generates digital drive data representative of an electronic signal which drives the display screen;

a signal converter coupled to the electronic probe, which converts the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an optical attribute for at least one pixel of the display screen; and

a frame storage coupled to the signal converter for storing the pixel data, wherein the signal converter samples a plurality of scan lines within a frame of the digital drive data and wherein at least one of the plurality of scan lines sampled is discarded and at least one other of the plurality of scan lines sampled is saved in the frame storage.

8. A test system for non-invasively testing a microcomputer system having one or more input stimulus signals and a display screen, the test system comprising:

a electronic probe which generates digital drive data representative of an electronic signal which drives the display screen;

a signal converter coupled to the electronic probe, which converts the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an optical attribute for at least one pixel of the display screen; and

a frame storage coupled to the signal converter for storing the pixel data, wherein the signal converter is coupled to a program means for converting the pixel data into bit-map data in a bit map, and wherein the program means adds a value of at least one of the plurality of pixel values sampled from a first one of the plurality of frames with a corresponding one of the plurality of pixel values sampled from a second one of the plurality of frames to generate a combined pixel value, and the combined pixel value is saved in the bit map.

9. The test system according to claim 8, wherein the bit map is organized as a structure, the structure comprising:

a pointer to a bit-map array of scan lines and pixels within scan lines; and

parameters which characterize the data in the array.

10. A method for non-invasively testing a microcomputer system having one or more input stimulus signals and an display screen, the method comprising the steps of:

generating digital drive data representative of an electronic signal which drives the display screen;

converting the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an attribute for at least one pixel of the display; and

storing the pixel data,

wherein the step of converting comprises the steps of;

retrieving a plurality of pixel values within each of a plurality of frames of the digital drive data;

combining at least one of the plurality of pixel values sampled from a first one of the plurality of frames with a corresponding one of the plurality of pixel values sampled from a second one of the plurality of frames in order to generate a combined pixel value; and

saving the combined pixel value.

11. The method according to claim 10, further wherein the pixel data comprises a value representing a color for at least one pixel of the display screen.

12. The method according to claim 10, further wherein the pixel data comprises a value representing an intensity for at least one pixel of the display screen.

13. The method according to claim 10, wherein the step of converting comprises the step of sampling the digital drive data at a plurality of points in time in order to derive the pixel data for one combined pixel value.

14. The method according to claim 10, wherein the step of converting includes the steps of:

combining the saved pixel data into bit-map data in a bit map, and wherein the step of combining includes the step of adding a value of at least one of the plurality of pixel values sampled from a first one of the plurality of frames with a corresponding one of the plurality of pixel values sampled from a second one of the plurality of frames to generate a combined pixel value; and

saving the combined pixel value in the bit map.

15. The method according to claim 14, wherein the bit map is organized as a structure, the structure comprising:

a pointer to a bit-map array of scan lines and pixels within scan lines;

the array of scan lines and pixels within scan lines; and

parameters which characterize the data in the array.

16. The method according to claim 10, further comprising the steps of:

coupling an analog test signal to an analog interface;

converting the analog test signal into a digital electronic signal that drives the display screen; and

testing, with a computer, the stored subset of the pixel data.

17. The method according to claim 16, further wherein the pixel data comprises a value representing a color for at least one pixel of the display screen.

18. The method according to claim 16, further wherein the pixel data comprises a value representing an intensity for at least one pixel of the display screen.

19. A method for non-invasively testing a microcomputer system having one or more input stimulus signals and an display screen, the method comprising the steps of:

generating digital drive data representative of an electronic signal which drives the display screen;

converting the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an attribute for at least one pixel of the display; and

storing the pixel data, wherein the step of converting includes the step of using a bit-masked change filter.

20. A method for non-invasively testing a microcomputer system having one or more input stimulus signals and an display screen, the method comprising the steps of:

generating digital drive data representative of an electronic signal which drives the display screen;

converting the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an attribute for at least one pixel of the display; and

storing the pixel data, wherein the pixel data is organized as a structure, the structure comprising;

a pointer to an array of scan lines and pixels within scan lines;

the array of scan lines and pixels within scan lines; and

parameters which characterize the data in the array.

21. A method for non-invasively testing a microcomputer system having one or more input stimulus signals and an display screen, the method comprising the steps of:

generating digital drive data representative of an electronic signal which drives the display screen;

converting the digital drive data into pixel data, wherein each of the pixel data comprise a value representing an attribute for at least one pixel of the display; and

storing the pixel data, wherein the step of converting includes the step of;

sampling a plurality of scan lines within a frame of the digital drive data and wherein at least one of the plurality of scan lines sampled is discarded and at least one other of the plurality of scan lines sampled is saved.