M. Amer Iqbal Qureshi
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- Điều hướng trang này:
- Symbol
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18F452 XTAL =20 ALL_DIGITAL =true Output PORTB Symbol SER = PORTB .0 ' Serial data Pin Symbol SRCLK = PORTB .1 ' Serial data Clock Pin Symbol SRClr = PORTB .2 ' Serial data Clear Symbol Latch = PORTB .3 ' Columns, Latch Symbol RowClk = PORTB .4 ' Row clock, to select new row Symbol Rowrst = PORTB .5 ' Row reset, selects row 0 High SRClr ' Turn off the serial register clear Remember, if no data is clocked to shift registers, they will be in state of 0 on their outputs, and since 0 on a column selects it, so all columns will be selected. A logical 1 on a column will turn the column off, and a 0 will turn the column ON. The PulsOut command gives a small high pulse on the specified pin. The number indicates duration of pulse. 2 in this case will give a 4us pulse. However thgis timing is not crucial for the function of display. SHOut is the command that transmits the contents of a byte, or word, as a stream of bits on a single pin. The arguments are the pin, on which data is to be transmitted, the Clock pin to be used to clock the shift registers, lsbfirst is a reserved word, indicating least significant bit first. So it will transmit, the bit 0 of data first and bit 7 last. The numbers in square brackets are the data to be sent. These are 4 bytes of data the first byte is sent first, from left side, the next three bytes push the first sent byte successively to right, so at the end of all 4 bytes the first Byte has been sent to the right most 8 columns. You can play with these four bytes to make various leds, ON. You must have noticed that the column corresponding to 0 is turned on. So to turn the entire row ON, just send this data: tải về 3.06 Mb. Chia sẻ với bạn bè của bạn:
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