- 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_OSPI[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 8-2
- Propagation delays and matching:
- A to B = E to F = (C to
D) / 2
- Matching skew: <
60pS
Note: The OSPI Board Loopback Hold time requirement
(described in Section 6.9.5.18, OSPI) is larger than the Hold time provided by a typical flash
device. Therefore, the length of MCU_OSPI[x]_LBCLKO pin to the MCU_OSPI[x]_DQS
pin (C to D) may need to be shortened to compensate.