The figure below shows several consecutive transfers while the chip select is active. Three delays can be programmed to modify the transfer waveforms:
- The delay between the deactivation and the activation of QCS, programmed by writing QSPI_MR.DLYCS. Allows to adjust the minimum time of QCS at high level.
- The delay before QSCK, programmed by writing QSPI_SR.DLYBS. Allows the start of QSCK to be delayed after the chip select has been asserted.
- The delay between consecutive transfers, programmed by writing QSPI_MR.DLYBCT. Allows insertion of a delay between two consecutive transfers. In Serial Memory mode, this delay is not programmable and DLYBCT is ignored. In this mode, DLYBCT must be written to ‘0’.
These delays allow the QSPI to be adapted to the interfaced peripherals and their speed and bus release time.
Figure 1. Programmable Delays
