58.6.2.1.2 Host Read Mode

$f_{\mathrm{SPCK}}\text{max}=\frac{1}{{\mathrm{SPI}}_0\left(\text{or }{\mathrm{SPI}}_3\right)+t_{\mathrm{valid}}}$

t_valid is the client time response to output data after detecting an SPCK edge.

For a nonvolatile memory with t_VALID (or t_v) = 5 ns, using SPI₃ at 3.3V, f_SPCKmax = 56 MHz.