Currently I am having an IMX6 board connected with LCD controller via SPI as shown below
Here SDO and SDI on Slave side are connected together via a resistor to the slave. Hence the SPI interface is 3- Wire.
I read some posts saying that for SPI 3-Wire to work, we need to connect MOSI to MISO via resistor, which is not the case above.
Can some one please tell me whether the above design will work for SPI 3-Wire ?.
Thanks in advance.
I didn't try this connection (SPI 4-wire to SPI 3-wire). So I cannot tell you the above design can work or not.
I tried to porting a LCD panel (SPI 3-wire). I just connect the MOSI to the LCD panel's SDA pin because I don't need to read the message from the panel to make it work.
I think another method is using GPIO pins as SPI. I remember there is GPIO-SPI in linux already. I think you may modify the code little bit so you may able to change GPIO read/write for the SPI read/write. Hope this information can help you.