I have different SPI peripherals operating at 3.3 and 5 V logic levels, with the MCU operating at 3.3 V. Therefore I use level shifters (in my case I used 74LV1T32GWH with the two inputs tied together) to communicate with the 5V peripherals, which works fine on its own.
However, it looks like the MISO signal of the 3.3V peripheral is now "absorbed" by the output pin of the 5-to-3.3V level shifter (probably because the output pin of the level shifter doesn't have a high input impedance?) and therefore no signal from the 3.3V peripheral arrives at the MCU.
What can I do to solve this problem? Can I add a diode between MISO and 5-to-3.3V level shifter? Or do I need some kind of additional buffer? (I suspect this is what open drain buffers are for?)
I would like to avoid using some Tri-State-Buffer where I have to actively enable the buffer, because then I would have to have an additional CS line for that (at least if i have several 5V-peripherals behind the level shifter which don't share a common CS line).