OSD3358 Linux

This is a project I made some time ago.

Board rev. v1.

Almost finished board straight out of a reflow oven. USB host port and Click board-header connectors still missing, will hand solder them later on.

Board was developed from scratch following Octavo Systems reference design. Multiple components were not available for ordering so it was not possible to just download their board design files and order the boards and components.

Board specs

Octavo Systems SiP ( System In Package OSD3358 ) containing:
TI AM335x ARM Cortex-A8 1GHz
512MB DDR3 Main memory
TPS65217 Power management IC
TL5209 Low-dropout voltage regulator
100+ passive components
64GB eMMC ( AM335x supporting only 32GB at the moment )
SD card slot
USB-A host port
Micro-USB client port
Some buttons and LEDs
BeagleBone Debian 10.03 ( with modified u-boot to be able to boot it on the custom board. )

After reflow soldering, under a magnifying glass

Board preview in EAGLE

Board layout in EAGLE

4 layer board
3V3 and GND layers hidden.
RED = top signal layer
BLUE = bottom signal layer.

Board manufacturing process

Ordering process was easy from https://jlcpcb.com/. They have this detailed process log.

You can also view videos of each step of the process which was interesting.

Bottom side of the board

Top side of the board without components

Board taped down to hold it in place

Board stencil

About to spread some solder paste

Spreading the solder paste on to the board

Solder paste spread on to the board

Picture taken through a magnifying glass.

Some of the components used in the board

All the components placed, before reflowing

Reflowing the board

Custom reflow controller board controlling 4 x 230V infrared heating elements through a 3v DC -> 230V AC SSR ( Solid State Relay ). Temperature is read through a K-type thermocouple connected to MAX31855 thermocouple-to-digital IC.

Testing reflow oven temperature plot

ORANGE line = target temperature
BLUE line = actual temperature.

Debugging linux not booting up issue

U-boot not recognizing the board ID because the EEPROM is empty. I had to skip the EEPROM board ID check on u-boot and re-build it.