Hi,
Using Open Collector mode of the SPI, putting the two pins together and a pull-up on the new created bus is a solution.
You will need your master to have 0xFF in its buffer when it should receive data as it will also send data (you shift in and out !!!).
Using the 0xFF data will allow you to avoid data collision on the newly created bus.
Cheers,
Alban.
Hello Jarin,
To avoid external signal routing issues, the simplest approach may be to use the SPI hardware for the 4-wire slave device, and your bit-banged routines for the 3-wire slave device. The same pin furnctionality would be allocated to the software interface as the hardware interface, but using the alternate GPIO. Of course, each slave device will need a separate SS connection, requiring a total of five pins for the two devices.
Regards,
Mac