Basic 8051 Tutorial 6 2015-04-17

We start with the SPI bus... The main idea behind serial buses is to save on micro-controller pins... SPI requires three pins or more if there are multiple devices.. The serial transfer on an SPI bus is circular.. The inputs and outputs of each buffer are connected and the shift is synchronized.
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As data is shifted out of the SDO pin of a micro, the data is shifted into the SDI pin of the device...The data in the device is simultaneously shifted back into the micro....

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