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Using GPIO Pin As SI & SO for SPI interface?

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qville_usm

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Hi...

I currently do a design using Fujitsu MB91F467 Microcontroller. Right after PCB fab, i found out that the connection for SO & SI pin to SPI EEPROM not according to hardware SPI standard. I've been thinking if i could posibly use the port function as standard GPIO for SPI purpose. The CS & SCK pin is correctly connected. Is anybody know about this? Or any related material suited my need now.

Thx in advance for looking at my problem.

Arigato..
 

Indeed you may use GPIO to make a spi interface. The problem is that if you don't use hardware support it will be a bit slower and will keep the processor busy. The microcontroler will have to control all signals as GPIO (CE, SCL, and MOSI and read MISO).
 
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    FvM

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I don't think it is possible to use the hardware SPI clock and custom MISO/MOSI data lines because you can't synchronize the clock with the data.
You have to do it either completely in hardware level for all lines (clock, DI, DO) or use custom pins (GPIO user controlled) for all three signals, a custom clock pin and turn it high/low synchronized with the data in your custom DI/DO pins

Alex
 

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