![]() ![]() When you're done using the peripheral, the line is made high again. There are two ways of connecting multiple peripherals to an SPI bus: In a shift register, this corresponds to the "latch" input, which transfers the received data to the output lines. In general, each peripheral will need a separate CS line.To talk to a particular peripheral, you'll make that peripheral's CS line low and keep the rest of them high (you don't want two peripherals activated at the same time, or they may both try to talk on the same CIPO line resulting in garbled data). Lots of peripherals will require lots of CS lines if you're running low on outputs, there are binary decoder chips that can multiply your CS outputs. Many microcontrollers have built-in SPI peripherals that handle all the details of sending and receiving data, and can do so at very high speeds. If you're using an Arduino, there are two ways you can communicate with SPI devices: (A good example is on the Wikipedia SPI page.) The SPI protocol is also simple enough that you (yes, you!) can write your own routines to manipulate the I/O lines in the proper sequence to transfer data. You can use the shiftIn() and shiftOut() commands. These are software-based commands that will work on any group of pins, but will be somewhat slow. #SPI SERIAL FLASH PROGRAMMER SCHEMATIC DIAGRAM FULL#. ![]()
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