Hardware Design
Pin Description
Except for interfaces explicitly marked as non-GPIO, power pins, and ground pins, the remaining X527 GPIOs can normally be multiplexed to I2C, UART, SPI, I2S, PWM, and other functions. Confirm multiplexing from the core-board schematic and T527/A527 datasheet.
GPIO Levels
Carrier-board peripheral I/O levels must match the corresponding X527 power domains. A mismatch can damage the SoC or peripheral.
| Power Domain | Supported Supply | X527 I/O Level |
|---|---|---|
| VCC-PC | 1.8V / 3.3V | 1.8V |
| VCC-PD | 1.8V / 3.3V | 3.3V |
| VCC-IO | 3.3V | 3.3V |
| VCC-PG | 1.8V | 1.8V |
| VCC-PE | 1.8V / 3.3V | 1.8V |
| VCC-PI | 3.3V | 3.3V |
| VCC-PJ | 1.8V / 3.3V | 3.3V |
| VCC-PM | 1.8V / 3.3V | 1.8V |
| VCC-PL | 1.8V / 3.3V | 3.3V |
| VCC-PK | 1.8V / 3.3V | 3.3V |
| VCC-LVDS0 | 1.8V | 1.8V |
| VCC-LVDS1 | 1.8V | 1.8V |
| VCC-MCSI | 1.8V | 1.8V |
Power Design
The X527 requires only the main supply for normal operation.
- Pins 101, 102, and 103 are
VCC-SYS-5Vmain power inputs. - The recommended supply capability is 5V/3A.
- Keep supply ripple below 100mV.
- Use power traces wider than 2mm where possible.
- Use at least five vias when the main supply changes layers.
- Pin 109 is the
DCDC43.3V output. - Pin 110 is the
CLDO33.3V output.
Parameter difference: The feature table rates DCDC4 at 3.3V/3A and CLDO3 at 3.3V/500mA, while the hardware-design text describes pins 109 and 110 together as a 3.3V/1A output. Use the core-board schematic, AXP717B configuration, and measurements as the final production references.
USB Design
The X527 provides three USB2.0 ports and one USB3.0 port. One USB2.0 port is used as a Device Type-C firmware-upgrade interface on the development board.
- USB2.0 nominal bandwidth is 480Mbps.
- USB3.0 nominal bandwidth is up to 5Gbps.
- Route differential pairs length-matched.
- The specified differential impedance is 90Ω ±10%.
- Maintain a continuous reference plane below the pairs.
HDMI Design
The X527 integrates one HDMI OUT controller with HDMI2.0 support.
- Route the HDMI high-speed pairs length-matched.
- The specified differential impedance is 100Ω ±10%.
- Poor impedance or skew control can cause missing colors, intermittent video, or no display.
MIPI Design
The hardware-design chapter states that the X527 supports one MIPI DSI interface and three MIPI CSI interfaces:
- MIPI DSI connects to a display panel.
- MIPI CSI connects to camera sensors.
- Route the MIPI high-speed pairs length-matched.
- The specified differential impedance is 100Ω ±10%.
Confirm the number of active interface instances, lane multiplexing, and resistor population from the core-board schematic.