SPRUIS4E March 2022 – January 2024
Common Processor board supports 2 Lane PCIe M2.0 standard, to interface external SSD device.
M.2 series receptacle with M-Keyed Mfr. Part# MDT320M01001 is used to attach the external SSD device on common processor board. The x2 lane PCIe interface signals SERDES2 of J721E SoC will be terminated with receptacle. SoC_I2C0 is used for SMBUS access. Voltage level translator (TCA9543APWR) circuit will be used to change the I/O level of SMBUS signals to 1.8 V. The link activation signal (WKUP) from PCIe connector is terminated to the test point TP85.
Reset: Reset signal to the SSD/add on module is controlled by GPIO expander. The GPIO signal is pulled low with a resistor 10K by default to ensure PCIe Reset (#PERST) remains asserted until SoC releases reset.
Clock: A clock generator (CDCI #2) is provided to drive 100MHz HCSL clock for PCIe add on cards and J721E SoC. Resistor options are provided to select the clock source either from SoC or clock generator.