General
Review and verify the following for the custom
schematic design:
- Reviewed above "Common
checklist for all sections" section of the user's guide.
- Required memory interface
configuration and recommended connections.
- IO level compatibility
between processor and attached device. Connection of attached device IO
supply and the IO supply for IO group referenced to (powered by) the OSPI0
interface signals.
- Provision for series resistor
and pulldown for OSPI0_CLK.
- Provision for pullups for
data and control signals.
- IO level compatibility
between processor and attached device.
- Implementation of reset logic
and connection of attached device reset input.
- Clock loop back configuration
based on the memory device and interface selected (OSPI/QSPI).
- Connection of DQS input from
memory (QSPI) or LBCLKO from processor (QSPI).
Schematic Review
Follow the below list for the custom schematic
design:
- The recommendation is to
compare the OSPI0 or QSPI0 memory interface with SK schematic implementation
for provisioning of parallel pulls, series resistors, and the resistor
values.
- The recommendation is to
compare implementation of attached device reset logic with the SK schematic
implementation.
- Series resistor (0Ω)
provision for OSPI0_CLK (close to processor clock output pin to control
possible signal reflections) and external pulldown (10kΩ) for OSPI0_CLK
(close to attached device clock input pin) to hold the attached device in
low state (there are cases where the clock is stopped or paused in a low
logic state and the pulldown option is consistent with this logic
state).
- Provision for pullups (10kΩ
or 47kΩ) are provided for data and control signals that can float (to
prevent the attached device inputs from floating until driven by the host).
The recommendation is to verify the supply source connected to the
pullups.
- Connecting the OSPI0 interface to multiple attached devices (more than x1
attached device) is not recommended or allowed.
- IO level compatibility
between processor and attached device. The attached device IO supply and the
IO supply for IO group VDDSHV1 referenced to (powered by) the OSPI0
interface signals are connected to the same supply source.
- Supply rail connected to the
IO supply for IO group VDDSHV1 referenced to (powered by) OSPI0 peripheral
and attached device IO supply follows the ROC.
- Implementation of external
loopback (based on the use case).
- Connection of DQS from OSPI
memory device and pulldown added for DQS input near to processor.
- Connection of OSPI0_LBCLKO
for QSPI memory device through 0Ω.
- Pulling up the reset input to
a high state during reset or supply ramp (is not recommended).
- Implementation of reset logic when used for boot using a 2-input (RESETSTATz
and processor IO) ANDing logic or using MAIN domain warm reset status output
RESETSTATz.
- When OSPI0 interface is not used for boot, the reset logic can be
implemented using a processor IO. A pulldown is recommended near to the
reset input.
Additional
- The recommendation is to verify
that the OSPI/QSPI/SPI Board Design and Layout Guidelines section of the
processor-specific data sheet is followed.
- In case OSPI/QSPI boot mode is
implemented, the recommendation is to verify the silicon errata, selected memory
meets the boot criteria described in the processor-specific TRM (or verify with
TI, recommend using E2E).