Question: are sdhc and sdxc cards interchangeable?
Answer: SDXC is an SD memory card format that is based on the SDA 3.0 specification. SD and SDHC cards are based on the SDA 2.0 specification. ... This difference is the reason that the new SDXC format is NOT backwards compatible with host devices that only take SD (128MB to 2GB) or SDHC (4GB to 32GB) cards.