SDFM operation with synchronous GPIO is defined by setting GPyQSELn = 0b00. When using this synchronized GPIO mode, the timing requirement for tw(GPI) pulse duration of 2tc(SYSCLK) must be met. It is important for both SD-Cx and SD-Dx pairs be configured with SYNC option. Table 5-65 lists the SDFM timing requirements when using the synchronized GPIO (SYNC) option. Figure 5-65, Figure 5-66, Figure 5-67, and Figure 5-68 show the SDFM timing diagrams.