Dennis Field / dvk-mx8m-bsb - History

Move the charge controller, USB-C TCPC, and RTC to I2C1

Since each of these ICs will be powered at the same time as the SoM regardless of the PWR_EN state, they should share the same I2C bus as the PMIC.

Change the capacitor C1718 near the ETH PHY's AVDDL2 pin 44 from 220nF to 2.2uF

Emcraft is also going to change this cap to 2.2uF.

Now using GPIO5_IO03 (P4.03) to put the class-D op-amp in shutdown and conserve energy when muted, make C1716 near the ETH PHY's DVDDL pin 47 220nF instead of 10uF (EmCraft suggested that this should be 100nF but their's is 220nF, asked why), added a 10k pull-down to PAM2841's ENA pin, added a 100nF cap to the smart card's C1 VCC pin, added a 1uF cap to the haptic motor circuit's 3V3_P rail

Still need to use I2C3 instead of I2C1 according to EmCraft's suggestions.

Move CAPTOUCH_~RST from BOOT_CFG_03 to GPIO1_IO05/P3.33 (was CSI_P2_PWDN), add a 10k pull-down to LCD_~RESET, make the corresponding changes to the BoM and netlist/layout

Having CAPTOUCH_~RST on BOOT_CFG_03 caused a voltage divider on the pin.

Fix all DRC violations in the layout by making corrections to various footprints

Make the ETH PHY's crystal's load capacitors 27pF instead of 22pF, Cstray should now be 3.5pF instead of 7pF

Replace camera's schottky+resistor level-shifter circuit with the more functional TXB0101 dedicated IC

Add proper WWAN reset circuit using a MMBT2222A NPN BJT along with a 100nF cap and a TVS diode, make needed adjustements to the WWAN's SIM card circuit (UIM-CLK and UIM-RESET caps are NC & added 4.7k series resistor to SIM_DETECT_O#), assign the MMBT2222A footprint to KiCad's official SOT-23 footprint (identical to the spec sheet's recommended land pattern)

If necessary, the NC cap pads on UIM-CLK and UIM-RESET can be tested with various values during the first prototype debugging phase.

Make recommended changes after reviewer examined pages 13, 15-20