As per MPSoC datasheet, SD initialization and booting of the PS is in high-speed mode and IO voltage level required is 3.3V. After initialization, the SD interface can operate at 1.8V to support the ultra-high-speed (UHS) SD cards.
To support different type SD cards which supports 1.8V & 3.3V IO voltages, PS SD signals from MPSoC is connected to SD connector through voltage level translator (NVT4857UKAZ). This level translator has a “SEL” pin which sets the IO voltage to 1.8V or 3.3V and connected through “PS_SD_PWR” pin of MPSoC. If this pin is high ‘1’ then IO level is 1.8V and this pin low ‘0’ then IO level is 3.3V. In carrier board, no external pullup/pulldown is mounted to this “SEL” pin.
Since no external pull down is mounted and SEL pin is floating during powerup, this pin sets IO voltage to 1.8V sometimes and affects the booting from carrier board SD connector.
This being a known issue with SD card booting in proto SOM/Kit and a fix is provided in the MP version carrier board. Because, Proto and MP carrier boards have different SD circuit. Errata attached for details.
Note: Errata is only applicable for MP version carrier board (G30D).
iW-RainboW-G30D-ZCU7_5_4-CarrierBoard-Errata-R2.0-REL1.0.pdf (355.7 KB)
For further inquiries, please get in touch with mktg@iwave-global.com
Please find the detailed G30D product information in the below link,