- The OSPI[x]_CLK output pin must
be connected to the CLK input pin of the attached OSPI/QSPI/SPI device
- The OSPI[x]_LBCLKO output pin
must be looped back to the OSPI[x]_DQS input pin
- The signal propagation delay of
the OSPI[x]_LBCLKO pin to the OSPI[x]_DQS pin (C to D) must be approximately
twice the propagation delay of the OSPI[x]_CLK pin to the attached OSPI/QSPI/SPI
device CLK pin (A to B)
- The signal propagation delay of
each OSPI[x]_D[y] and OSPI[x]_CSn[z] pin to the corresponding attached
OSPI/QSPI/SPI device data and control pin (E to F, or F to E) must be
approximately equal to the signal propagation delay from the OSPI[x]_CLK pin to
the attached OSPI/QSPI/SPI device CLK pin (A to B)
- 50Ω PCB routing is recommended
along with series terminations, as shown in Figure 8-2
- Propagation delays and matching:
- (C to D) = 2 x ((A to B)
± 30ps), see the exception note below.
- (E to F, or F to E) = ((A
to B) ± 60ps)
Note:
The External Board Loopback hold
time requirement (defined by parameter number O16 in the OSPI0 Timing
Requirements - PHY DDR Mode section) may be larger than the hold time
provided by a typical OSPI/QSPI/SPI device. In this case, the propagation delay
of OPSI[x]_LBCLKO pin to the OSPI[x]_DQS pin (C to D) can be reduced to provide
additional hold time.