Dennis Field / dvk-mx8m-bsb - History

Use a DP3T switch to select between eMMC, USB (serial download), and uSD boot devices, corrected the SW_BACK and SW_HOME buttons to have 33Ohm pull-ups instead
of pull-downs since the respective boot config lines have pull-downs already set

These buttons should be untouched during boot otherwise the board will not boot properly (pressing SW_HOME during boot causes "SD power cycle enable/eMMC reset enable" and pressing SW_BACK causes the uSD to be treated as a 4-bit bus if it's the boot device otherwise it's a BOOTCONFIG[6:4]=011 "reserved" condition)

Add haptic/vibration motor circuit

Using a PFET to switch the high-side. The motor will likely be coin-shaped with adhesive on the back to stick to a designated spot on the board and have a 2-pin Molex or JST connector installed on the wire leads (by request).

Add NOR flash chip schematic, use mini-HDMI (requested) instead of micro and add its corresponding properties and footprint, use 3.5mm CTIA headset jack with through-hole pins rather than an SMD one for extra "mechanical rigidity"

Will likely want to use a USB-C receptacle with through-hole shield pins.

Add Proximity+Ambient Light sensor and 9-axis IMU circuits to the "sensors" schematic sheet, include the associated footprints and assign them to the respective symbols

The 9-axis IMU is configured to use I2C(1) rather than SPI. Notes are included regarding the IMU's setup. Descriptions of the IMU state that it is "fully compliant with Android" and therefore drivers must be available.

Add HDMI schematic and connector footprint (using SMD type D/micro-HDMI receptacle)

Add built-in speaker and class-D amplifier to drive it from lineout, use an anal
og SPDT switch to select internal or external mic via software (GPIO), select sp
ecific 8Ohm SMD speaker and SMD -37dB passive 2 terminal microphone (2.2kOhm output impedance)

Introduce a method to switch between built-in and headset microphone depending on the presence of something plugged into the 3.5mm headphone jack, included notes regarding measurements, simulations, and various findings for the headset/built-in mic opperation

Zener diode included to protect the GPIO pin against under/over voltage from HP_OUT. Schmitt-trigger inverted at the enable pin of the analog switch for some debouncing.

Add ethernet PHY schematic, assign the RGMII signals, and include its associated 48-QFN footprint

Assign verious signals such as W_DISABLE1, W_DISABLE2, WWAN_DISABLE; reorder the hierarchy to make more sense; add "solid" graphic lines around the power signals on the top sheet for clarity

Organize the USB-C, Battery, and Power sheets at the top-level such that the power-flow makes more sense when reading the schematic