外文翻譯--基于stc單片機(jī)的紅外遙控開關(guān)系統(tǒng)的設(shè)計(jì)(編輯修改稿)
2025-02-14 15:13 本頁面
【文章內(nèi)容簡介】 odulated signals. Modulated receivers are available from Sharp and Lite On, part numbers GP1U521Y and LT1060 respectively. The nonmodulated type is available from Quality Technologies part number QSE157QT.The choice of the PIC16C57 is not indicative of the processing power required for decoding. Typical IR receiver code can ?t into less than half the ROM space available in a PIC16C54, and uses four RAM choice of a PIC16C57 in this case was driven by the need to store a lot of signal lengths for later reading.A ceramic resonator clocks the PIC16C57. It will give adequate frequency accuracy to determine pulse and gap lengths. A RC network does not usually have adequate accuracy. A button is available for resetting the PIC16C57, and four jumpers are provided to control the application startup. The two digit display is multiplexed and driven through Q1 and Q2.Three octal switches are used as inputs to control the OPTION register and which ?le is displayed. The whole circuit derives its power from a 9V, 200 m A wall mounted supply. U1 regulates the 9V down to 5V for the PIC16C57 and associated circuitry.DESCRIPTION OF SOFTWARE TO AID DEVELOPMENTThis application uses four different firmware files. IRMAIN. ASM controls the selection of the three application files. The first file is MEASURE. ASM which stores the infrared burst and gap lengths into memory and allows playback of that decodes NEC6121 infrared format and displays the received codes on the LED display. The final file, , shows the final firmware for decoding the infrared format for a Teknika Television. The firmware listed includes three applications that will aid in designing an infrared control system. IRMAIN. ASM reads jumpers 1 and 2 and directs program flow after reset to one of the three applications. Having no jumper in 2 will direct program flow to jumper in 2 only will direct program flow to in both 1 and 2 will direct program flow to TEKNIKA. ASM. Jumpers 3 and 4 are not used.This is the most basic and most useful of the three applications. This program stores the infrared burst and gap lengths into memory, allowing playback of the measure ments through the two digit display. It allows external control of the OPTION register also, through setting of SW1 is read directly into the OPTION register prescaler value for SW1 is changed during program operation, the PIC16C57 resets.Upon startup a “hyphen”will be displayed in the left digit space until the infrared input settles to the dark logic indicating that the unit is ready to receive an infrared signal.As an infrared signal es in, the lengths of bursts of infrared, and the lengths of gaps between burst are stored in consecutive file locations until all four pages of the PIC16C57’s memory files are filled. If a jumper had been in 1, the program throws away the first 32 pulse and gap lengths and starts storing pulse and gap lengths with the thirty third pulse length. This allows the decoding of very long formats.When all four pages of file memory are filled with pulse and gap lengths, a number and decimal point are displayed. The decimal point indicates that the unit is donereading. The number is a gap or pulse and SW3 control the time sequence of the pulse or gap length displayed. These are in octal with SW3 being the more significant digit.INSTRUCTIONS ON WRITING AN ALGORITHM TO DECODE IR REMOTES1. To design a system that uses an infrared remote control, the first step is to choose a remote control. Self designed or off the shelf, modulated or unmodulated are the primary technical decisions. 2. Once a remote control has been chosen or designed, its modulation frequency, if it has one, must be determined. This controls the kind of hardware used to receive the infrared signal. 3. The next step is to determine the timebase of the data, that is, if the pulses and gaps are short or long in reference to the PIC16C57 clock. The OPTION switch, SW1, is used to get optimum length pulse and gap counts from TMR0. This defines the value of the OPTION prescaler. 4. Fourth, definition is made as to what, in the format, defines a 39。139。, and what, in the format, defines
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