General
Review and verify the following for the custom
schematic design:
- Reviewed above "Common checklist for all sections" section of the
user's guide.
- Memory selected confirms to the JEDEC (JESD209-4B) standard.
- Supported memory configuration.
- The recommendation is to add layout notes on the schematic (the
recommendation is to follow the AM62x, AM62Lx DDR Board Design and Layout
Guidelines).
- Supply rails connected to the processor DDRSS peripheral supply rail and
the attached memory device IO.
- Connection of address, clock, control and data signals.
- Connection of DDRSS RESETn signal to LPDDR4_RESET_N memory reset input.
- Connection of chip select CSn0, CSn1 to the attached memory device.
- ODT pullup connection, DDR CAL0 and Memory ZQn resistor connections.
- Swapping of Data Bit or Data Byte.
Schematic Review
Follow the below list for the custom
schematic design:
- 1x1 6-bit is the only supported memory configuration.
- The recommendation is to compare the bulk and decoupling capacitors used and
values with relevant SK schematic implementation.
- Supply rails connected to the processor DDRSS peripheral supply and the
attached memory device IO follow the processor and attached memory device
ROC.
- Connection of address, clock, control and data signals. For LPDDR4 memory
interface, x16 is the only supported data bus width. For connecting the
DDRSS to 16-bit memory device - refer AM62x, AM62Lx DDR Board Design and
Layout Guidelines.
- Connection of DDRSS RESETn signal directly to LPDDR4_RESET_N memory reset
input (to hold the signal low during power-on initialization). The
recommendation is to add a pulldown (10kΩ) for DDRSS RESETn signal and place
close to the memory device reset input pin.
- Connection of chip select CSn0, CSn1 to the attached memory device. Follow
AM62x, AM62Lx DDR Board Design and Layout Guidelines based on
selected memory
- Memory device ODT pulled up through a resistor (2.2kΩ used on SK, the
recommendation is to not connect DDRSS signals and follow the SK
schematics).
- DDR0_CAL0, DDRSS IO pad calibration resistor (240Ω, ±1%) connected across
DDR0_CAL0 and VSS.
- ZQ0 Memory device IO calibration resistor (240Ω, ±1%) connected across ZQ
and VDD_LPDDR4.
- Data Bit or Byte Swapping. Follow AM62x, AM62Lx DDR Board Design and
Layout Guidelines.