User Guide

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The 96Boards specification calls for two I2C interfaces to be implemented on the Low Speed Expansion Connector.
The DB8 implements both interfaces, I2C0 and I2C1 that connects directly to the APQ8096 SoC. A 2.2K resistor is
provided as pull-up for each of the I2C lines per the I2C specifications, these pull-ups are connected to the 1.8V voltage
rail.
6.3 GPIO {A-L}
The 96Boards specifications calls for 12 GPIO lines to be implemented on the Low Speed Expansion Connector. Some of
these GPIOs may support alternate functions for DSI/CSI control
The DB8 implements this requirement. 11 GPIOs are routed to the APQ8096 SoC and one GPIO is connected to the
on-board PMIC. All are 1.8V signals. Reference the connector pinout table for details regarding GPIO assignments
● Note: GPIO C - Connects to GPIO_125 of APQ8096 SoC, can serves as TS_INT0 supporting the
96Boards requirements to create a wake-up event for the SoC.
6.4 SPI 0
The 96Boards specification calls for one SPI bus master to be provided on the Low Speed Expansion Connector.
The DB8 implements a full SPI master with 4 wires, CLK, CS, MOSI and MISO all connect directly to the APQ8096 SoC.
These signals are driven at 1.8V.
6.5 PCM/I2S
The 96Boards specification calls for one PCM/I2S bus to be provided on the Low Speed Expansion Connector. The CLK, FS
and DO signals are required while the DI is optional.
The DB8 implements a PCM/I2S with 4 wires, CLK, FS, D0 and DI. The I2S signals are connected directly to the APQ8096
SoC. These signals are driven at 1.8V.
6.6 Power and Reset
The 96Boards specification calls for a signal on the Low Speed Expansion Connector that can power on/off the board and a
signal that serves as a board reset signal.
The DB8 routes the PWR_BTN_N (named PHONE_ON_N on DB8 schematic) signal to the KYPDPWR_N pin of the PMI8996
PMIC. This signal is driven by S2 as well, the on-board power on push-button switch. Please note that the push button only
provides an On/Sleep function and not OFF functionality.
A mezzanine implementation of this signals should not drive it with any voltage, the only allowed operation is to force it to
GND to start the board from a sleep mode. A board shutdown will occur when this signal is held to ground for more than
15 seconds.