MCP4151's scary SDI/SDO multiplexing thing.

Yesterday when I read the MCP4151 datasheet, I found a strange thing called SDI/SDO multiplexing.


*** From MCP4151 datasheet ***

SDI/SDO multiplexing (MCP41X1 only)


3.3 Serial Data In / Serial Data Out (SDI/SDO)

On the MCP41X1 devices, pin-out limitations do not allow for individual SDI and SDO pins. On these devices, the SDI and SDO pins are multiplexed.

The MCP41X1 serial interface knows when the pin needs to change from being an input (SDI) to being an output (SDO). The Host Controller’s SDO pin must be properly protected from a drive conflict.

*** End MCP4151 datasheet ***


I think this is scary, because any careless mistake might cause white smoke rising at my RPi.  This is for sure not for SPI newbies.

So I decided not to touch this SDI/SDO multiplexing MCP4151.  I visited MCP and found they has MCP4251 which is not SDI/SDO multiplexed.  TaoBao sells for RMB10 each.  I think this is safer for newbies messing with.  So I bid a couple of them.

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