Browse Prior Art Database

AUTOMATED BANK LED AND KEY SCANNING

IP.com Disclosure Number: IPCOM000198372D
Publication Date: 2010-Aug-05
Document File: 2 page(s) / 12K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention discloses a method of updating display or providing light-emitting diode (LED) refresh rates without causing visible flickers on the display. Further, the method uses a module such as a Direct Memory Access (DMA) or Data Transfer Controller (DTC). Such DMA or DTC modules are used to automate the scanning of LED and key banks on low-level embedded controls. Use of DMA or DTC modules allows control processing unit (CPU) to be free for other tasks or to enter a sleep mode.

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AUTOMATED BANK LED AND KEY SCANNING

BACKGROUND

The present invention relates generally to light-emitting diode (LED) refresh rates for a display without visible flickers, and more particularly to use of modules to automate the scanning of LED and key banks on low level embedded controls.

In general, each bank of LEDs or display needs to be updated at a rate, referred to as refreshment rate, fast enough that the human eye does not detect any flicker. Usually, 120Hz is sufficient to avoid such flicker. However, if processor load is too high, the LED refresh rate suffers and results in a visible flicker on the display. Such flickers can easily cause eyestrain and headaches for users of the device with such bank of LED or displays.

Numerous conventional techniques are employed to avoid visible flickers on the display. Some conventional techniques use nested interrupts that involve enabling interrupts within interrupts. However such conventional techniques are not preferred, because usually an interrupt is a process or a signal that stops microprocessor or microcontroller working on other instructions and forces to update the display.

It would be desirable to have a method of avoiding flickers on the display without discontinuing or stopping the microprocessor or microcontroller function.

DETAILED DESCRIPTION

The present invention discloses a method of updating display or providing light-emitting diode (LED) refresh rates without causing visible flickers on the display. Further, the method reduces appearance of the flickers on the display without discontinuing or stopping the microprocessor or microcontroller work on other instructions.

The method described herein uses a module such as, a "Direct Memory Access" (DMA) or "Data Transfer Controller" (DTC). Such DMA or DTC modules are used to automate the scanning of LED and key banks on low-level embedded controls. The use of these DMA or DTC modules enables the Central Processing Unit (CPU) to be free for other tasks, or to enter

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