Dear Mr Erik Malund,
but he wants to check the high impendance state. Is it possible with SPI you think? High impedance state is open output. If you have a push-pull resistor it looks the same like logic high state. If you are not using push-pull, TTL inputs detect high impedance state also as logic H. Do you mean is it possible to find to solution except verifing the memory contents?
Greetings, Jacek Bogusz