JPH0451287A - Led dynamic driving system - Google Patents

Abstract

PURPOSE:To eliminate the application of the burden of processing on a CPU by executing the dynamic driving of LEDs by DMA. CONSTITUTION:First, the information on the lighting and flickering driving of 16 pieces of the LEDs 105 is set by the CPU 100 into a memory 101. The DMA (direct memory access) device 102 transfers the data of 4 byte of the memory 101 by 1 byte each at a specified period to a latch device 103. The DMA device 102 repeats the transfer from the top of the memory 101 again when the transfer of the 4 byte ends. A line driver 104 which outputs line data is connected to upper 4 bits of the latch device 103 and is activated successively by each one by the set data of the memory 101. The LEDs 105 are connected in 16 pieces in the form of matrix to the lower 4 bits of the line driver 104 and the latch device 103. The LEDs 105 existing at the intersected points of the line of the activated line driver 104 and the latch device 103, the lower 4 bits of which are 1, are lighted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an LED (liquid crystal display element) dynamic drive system.

[Conventional technology]

Conventionally, when driving an LED to blink, the CPU periodically
This was achieved by controlling the ED drive device.

[Problem to be solved by the invention]

However, if the LED driving device is periodically controlled by the CPU, there is a problem that the CPU processing takes time and other processing becomes slow.

[Means to solve the problem]

The LED dynamic driving method of the present invention uses a plurality of LEDs.
(a liquid crystal display element); a latch means that holds the on/off light driving information for driving the LED in units; and the on/off light held in the latch means. The apparatus includes an LED driving means for blinking the LED based on the driving part movement information, and a direct memory access means for reading out the lighting-on/off-light driving information from the memory means and transferring it to the latch means.

Further, the plurality of LEDs are arranged in a matrix, and one unit of the on/off light driving information held in the latch means corresponds to the matrix.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In this example, 16 LEDs are controlled using a 4 row and 4 column matrix. First, the CPU 100 controls the 16 LEDs.
The on/off lamp drive information 105 is set in the memory 101.

The memory 101 is composed of 4 bytes, and each byte holds information on whether the four LEDs 105 are turned on or off in one row. Here, the upper 4 bits represent the information in which row by setting only 1 bit of the 4 bits to 1, and the lower 4 bits represent the on/off lights of the LEDs 105 in each column of the row represented by 1 and 0. expressing. Among these, the upper 4 bits are fixedly set, and only the lower bits are rewritten by the CPU 100 according to whether the LED 105 turns on or off.

A DMA (direct memory access) device 102 transfers 4 bytes of data in the memory 101 to a latch device 103 one byte at a time at regular intervals. When the transfer of 4 bytes is completed, the DMA device 102 repeats the transfer from the beginning of the memory 101. In this way, the DMA device 102 causes the latch device 103 to turn on the LED 105 set in the memory 101. The driving information for turning off the light is repeatedly set at a constant cycle.

A row driver 104 that outputs row data is connected to the upper four bits of the latch device 103, and is activated one by one according to setting data in the memory 101. LED
105 are connected to the row driver 104 and the lower 4 bits of the latch device 103 in 16 pieces in matrix form, and are connected to the row of the activated row driver 104 and the latch device 103.
L at the intersection with the lower 4 bits of
ED105 lights up.

In this way, the CPU 100 only needs to set the on/off lamp drive information in the memory 101 once, and the subsequent control is performed using the DMA.
The device 102 does this autonomously.

FIG. 2 shows an example in which the memory 101 in FIG. 1 is expanded. This expansion memory 200 has a configuration in which a plurality of memories 101 in FIG. 200 data. By appropriately setting 0 and 1 to bits corresponding to the same LED 105 in the extended memory 200, it is possible to perform arbitrary blinking.

〔Effect of the invention〕

As described above, according to the present invention, dynamic driving of the LED is performed using DMA, thereby eliminating the burden of processing on the CPU.

[Brief explanation of the drawing]

FIGS. 1 and 2 are configuration diagrams showing one embodiment of the present invention. ioo...CPU, 101...Memory, 102...
・DMA device, 103... Latch device, 104...
Row driver, 105...LED, 200...Extended memory.

Claims (1)

[Scope of Claims] 1. A memory means for holding on/off driving information for a plurality of LEDs (liquid crystal display elements), and a latch means for holding the on/off driving information for each unit for driving the LEDs. , LED driving means for blinking the LED according to the on/off light drive information held in the latch means, and direct memory access means for reading the on/off light drive information from the memory means and transferring it to the latch means. The LED dynamic drive system is characterized by: 2. The plurality of LEDs are arranged in a matrix of rows and columns, and one unit of the on/off light driving information held in the latch means corresponds to the matrix of the rows and columns. LED dynamic drive system.