Dennis Field / dvk-mx8m-bsb - History

Include reverse polarity protection circuit along with a simulation showing its effectiveness

Protecting VBAT from when board is sinking current via USB C. Protects against reverse polarity at the DC jack.

In EmCraft's instance VBUS should only be 5V when sinking current but they must protect against the condition when VBUS>12V and DC_IN=12V. This may need testing.

Move reference designators in the schematic so that they are legible

Use "Start to sheet number*100 and use first free number" designation, any new component added to the schematic will occupy the next available number in that sheet

For example: if sheet 2 has R201-R215 and we add a new resistor it will become R216.

Assign all associated signals to their respective pins on the EmCraft i.MX8M SoM

The ERC is now at the same state as the DART SoM schematic. Need to compare various aspects of the current schematic against the EmCraft reference design. The main buck-boost will likely need to be switched to a 5V regulator, or be configured to output 5V.

A regulator will likely need to be added which will output some VBAT voltage level (3.5~4.2V) for the M.2 cards. The SIM7100 for example requires at least 3.4V!

Bring out M.2 signals to the main sheet and attach WoWWAN and RESET

Add notes regarding the WWAN M.2's USB interface. The Emcraft SoM has NAND_CE3_B available for the DISABLE pin. Still need to select which pin will be used for CONFIG_1.

Add sim card slot, ESD protection, and relevant notes regarding the expected M.2 configuration

Add 3.0V LDO for display's VCI and TP_VCC, include a 3~12ms rise time delay for the 1.8V rail to turn on before the 3.0V rail, begin the WWAN M.2 schematic (found a a low-profile key B connector)

Add MIPI DSI, cap touch interface, and AMOLED display regulator circuits

TPS65632's components were selected based on the best match and price based on suggestions. The RT4720 does not seem to be sold by any distributors.

Add JTAG and buttons & LED schematics, reorder based on priority (especially for debugging/development)