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Hardware Design

Pin Multiplexing​

Except for dedicated high-speed signals, power pins, and grounds, selected signals can be multiplexed as I2C, UART, SPI, I2S, PWM, or GPIO. Before carrier-board release, verify:

  • Reset state and pull resistors.
  • I/O voltage domains.
  • Multiplexing conflicts.
  • Drive capability and external loading.

Power Design​

  • Pins 101, 102, and 103 are VSYS 5V inputs; use a supply rated for at least 3A.
  • Keep main-supply ripple below 100mV.
  • Use power traces wider than 2mm where possible and at least five vias for layer transitions.
  • Pin 77 is VIO18_PMU. The hardware-design text states approximately 600mA, while the feature table states 500mA. Use the current schematic, PMIC configuration, and measured margin for production.
  • Pin 79, VCN33_1_PMU, is a 3.3V output rated at 800mA in the manual.
  • Pin 80, VCN18_PMU, is a 1.8V output rated at 1.2A.
  • Pin 81, VIO28_PMU, is a 2.8V output rated at 200mA.

USB Design​

The core board exposes three USB2.0 interfaces and one USB3.0 interface. Micro USB on the development board is used as the firmware-upgrade Device port.

  • USB2.0 nominal bandwidth: 480Mbps.
  • USB3.0 nominal bandwidth: up to 5Gbps.
  • Route differential pairs length-matched.
  • Control differential impedance to 90Ω ±10%.
  • Maintain a continuous reference plane and avoid unnecessary vias.

HDMI Design​

The MT8390 integrates HDMI OUT with HDMI 2.0 support.

  • Match lengths within and between the high-speed pairs.
  • Control differential impedance to 100Ω ±10%.
  • Maintain a continuous reference plane.
  • Minimize vias, stubs, and connector discontinuities.

Poor impedance or skew control can cause missing colors, intermittent output, or no display.

MIPI Design​

The core board supports two MIPI DSI and two MIPI CSI interfaces.

  • Route differential pairs length-matched.
  • Control differential impedance to 100Ω ±10%.
  • Confirm whether multiplexed pins operate as DSI or CSI in the target design.
  • Match camera supplies, MCLK, RESET, PWDN, and I2C voltage to the sensor.
  • Follow the panel specification for display power, reset, backlight, and touch sequencing.

PCIe, DP, and eDP​

PCIe, DisplayPort, and eDP are high-speed interfaces. The supplied manual does not provide a complete loss, length, and via budget. Use the MediaTek hardware design guide, core-board schematic, and target connector specification as the final PCB references.