74.6.6.1.1 Maximum FLEXCOM SPI Frequency

The following formulas provide the achievable SPI frequency in Host Read and Write modes and in Client Read and Write modes. When the result of these formulas exceeds the f_{SPCK_MAX} parameter provided in Table 74-29, f_{SPCK_MAX} applies.

Host Write Mode

Where t_{SU_CLIENT} is the input setup time of the client device.

Host Read Mode

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

Where 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, f_SPCK = 40 MHz.

Client Read Mode

Where t_{VALID_HOST} is the host’s delay between the SPCK edge and the output data valid.

Client Write Mode

$f_{\mathrm{SPCK}}=\frac{1}{{\mathrm{}2x(S\mathrm{PI}}_{6\max }\left(\text{or }{\mathrm{SPI}}_{9\max }\right)+t_{\mathrm{setup}})}$

Where t_setup is the setup time from the host before sampling data.