67.18.1 Maximum QSPI Frequency

The following formulas give maximum QSPI frequency in Host Read and Write modes.

• Host Write Mode

  The QSPI sends data to a client device only, e.g. an LCD. The limit is given by QSPI₂ (or QSPI₅) timing.

• Host Read Mode

  $f_{\mathrm{QSCK}}\max =\frac{1}{{\mathrm{QSPI}}_0\left(\text{or }{\mathrm{QSPI}}_3\right)+t_{\mathrm{VALID}}}$

  t_VALID is the client time response to output data after detecting a QSCK edge.

  The f_QSCK max is given between the maximum frequency given by the above formula and the pad I/O limitation.