- The MCU_OSPI[x]_CLK output signal must be connected to the CLK pin of the flash device
- The MCU_OSPI[x]_LBCLKO output signal must be looped back into the MCU_OSPI[x]_DQS input
- The signal propagation delay from the MCU_OSPI[x]_CLK pin to the flash device CLK input pin (A to B) should be approximately equal to half of the signal propagation delay from the MCU_OPSI[x]_LBCLKO pin to the MCU_OSPI[x]_DQS pin ((C to D)/2). See the note below.
- The signal propagation delay from the MCU_OSPI[x]_CLK pin to the flash device CLK input pin (A to B) must be approximately equal to the signal propagation delay of the control and data signals between the flash device and the SoC device (E to F, or F to E)
- 50 Ω PCB routing is recommended along with series terminations, as shown in Figure 7-2
- Propagation delays and matching:
- A to B = E to F = (C to D) / 2
- Matching skew: < 60 ps
Note: The OSPI Board Loopback Hold time requirement
(described in OSPI) is larger
than the Hold time provided by a typical flash device. Therefore, the length of
MCU_OPSI[x]_LBCLKO pin to the MCU_OSPI[x]_DQS pin (C to D) can be shortened to
compensate.