Video Touch Sample Blanking to Avoid Noise on Pen and Touch
A system, method, and computer-readable medium are disclosed for performing a display device noise reduction operation. In certain embodiments, the display device noise reduction operation synchronizes the clocks between a Scalar clock signal (e.g., a Master clock), a touch device (such as an active pen type touch device), and touch controller clock signals. Additionally, in certain embodiments, a line sample blanking signal (SAMPLE_BLANK) is routed to a pen controller such as an EMR pen controller and a touch controller. The line sample blanking signal being asserted indicates that the display is clocking in a line of the display.
1 . A computer-implementable method for reducing display device noise, comprising:
synchronizing a master clock signal, a pen clock signal and a touch clock signal;
generating a blanking signal based upon the pen clock signal and the touch clock signal, the blanking signal indicating to a display the display is clocking in a line of the display, the blanking signal causing the display to ignore pen and touch samples that are taken from the line of the display during a blanking period set forth by the blanking signal being active.
2 . The method of claim 1 , wherein:
synchronizing the master clock signal, the pen clock signal and the touch clock signal is performed by multiplying and dividing a scalar clock signal to support pen and touch frequencies, by synchronizing the master clock signal, the pen clock signal and the touch clock signal pen and touch sampling is timed to only sample when the display device is not clocking in a new line.
3 . The method of claim 1 , wherein:
the pen clock signal is associated with an active pen.
4 . The method of claim 3 , wherein:
the active pen comprises an active pen tip, an active pen button and an active pen blunt end, and
the pen clock signal comprises an active pen tip frequency, an active pen button frequency and an active pen blunt end frequency.
5 . The method of claim 4 , wherein:
the blanking signal has an active pen tip time period based upon the active pen tip frequency, an active pen button time period based upon the active pen button frequency and an active pen blunt end time period based upon the active pen blunt end frequency; and,
the active pen tip time period is used when the display senses the active pen tip, the active pen button time period is used when the display senses the active pen button and the active pen blunt end time period is used when the display senses the active pen blunt end.
6 . The method of claim 3 , wherein:
the active pen comprises an electro-magnetic resonance (EMR) type active pen.
7 . A system comprising:
a processor;
a data bus coupled to the processor; and
a non-transitory, computer-readable storage medium embodying computer program code, the non-transitory, computer-readable storage medium being coupled to the data bus, the computer program code interacting with a plurality of computer operations and comprising instructions executable by the processor and configured for:
synchronizing a master clock signal, a pen clock signal and a touch clock signal;
generating a blanking signal based upon the pen clock signal and the touch clock signal, the blanking signal indicating to a display the display is clocking in a line of the display, the blanking signal causing the display to ignore pen and touch samples that are taken from the line of the display during a blanking period set forth by the blanking signal being active.
8 . The system of claim 7 , wherein:
synchronizing the master clock signal, the pen clock signal and the touch clock signal is performed by multiplying and dividing a scalar clock signal to support pen and touch frequencies, by synchronizing the master clock signal, the pen clock signal and the touch clock signal pen and touch sampling is timed to only sample when the display device is not clocking in a new line.
9 . The system of claim 7 , wherein:
the pen clock signal is associated with an active pen.
10 . The system of claim 9 , wherein:
the active pen comprises an active pen tip, an active pen button and an active pen blunt end, and
the pen clock signal comprises an active pen tip frequency, an active pen button frequency and an active pen blunt end frequency.
11 . The system of claim 10 , wherein:
the blanking signal has an active pen tip time period based upon the active pen tip frequency, an active pen button time period based upon the active pen button frequency and an active pen blunt end time period based upon the active pen blunt end frequency; and,
the active pen tip time period is used when the display senses the active pen tip, the active pen button time period is used when the display senses the active pen button and the active pen blunt end time period is used when the display senses the active pen blunt end.
12 . The system of claim 9 , wherein:
the active pen comprises an electro-magnetic resonance (EMR) type active pen.
13 . A non-transitory, computer-readable storage medium embodying computer program code, the computer program code comprising computer executable instructions configured for:
synchronizing a master clock signal, a pen clock signal and a touch clock signal;
generating a blanking signal based upon the pen clock signal and the touch clock signal, the blanking signal indicating to a display the display is clocking in a line of the display, the blanking signal causing the display to ignore pen and touch samples that are taken from the line of the display during a blanking period set forth by the blanking signal being active.
14 . The non-transitory, computer-readable storage medium of claim 13 , wherein:
synchronizing the master clock signal, the pen clock signal and the touch clock signal is performed by multiplying and dividing a scalar clock signal to support pen and touch frequencies, by synchronizing the master clock signal, the pen clock signal and the touch clock signal pen and touch sampling is timed to only sample when the display device is not clocking in a new line.
15 . The non-transitory, computer-readable storage medium of claim 13 , wherein:
the pen clock signal is associated with an active pen.
16 . The non-transitory, computer-readable storage medium of claim 15 , wherein:
the active pen comprises an active pen tip, an active pen button and an active pen blunt end, and
the pen clock signal comprises an active pen tip frequency, an active pen button frequency and an active pen blunt end frequency.
17 . The non-transitory, computer-readable storage medium of claim 16 , wherein:
the blanking signal has an active pen tip time period based upon the active pen tip frequency, an active pen button time period based upon the active pen button frequency and an active pen blunt end time period based upon the active pen blunt end frequency; and,
the active pen tip time period is used when the display senses the active pen tip, the active pen button time period is used when the display senses the active pen button and the active pen blunt end time period is used when the display senses the active pen blunt end.
18 . The non-transitory, computer-readable storage medium of claim 13 , wherein:
the active pen comprises an electro-magnetic resonance (EMR) type active pen.