We have been working nonstop this month and the last to get DVT2 into production and assembled before Chinese New Year. All factories take a holiday from February 5th to February 18th. Chinese New Year is on February 11th this year.
The process of verifying everything again was really worth it. We discovered an issue with the LCD pinout. Luckily, we had not yet ordered the PCBs and could change the pinout on the connector in less than half a day.
There were over a hundred changes and refinements made to the schematic, layout and BOM. Many were minor cosmetic changes to the schematic and some were major including moving and re-routing some components to accommodate the new antenna. We also swapped some data lines in the LPDDR3 Memory in DVT2 to make it function properly.
The latest schematic and layout has been open sourced and released on GitHub. You can click here to check out the latest files. We will release the design files after we start shipping Pocket P.C.
Getting a PCB Fabrication House to produce 10-Layer impedance controlled PCBs before Chinese New Year was a difficult challenge. We tried numerous PCB services and companies we know or have worked with in the past and none could start production until after the holiday. Many companies are trying to get existing orders out of the door and are not taking new orders.
Fortunately, one of our team members checked with one of his long term partner factory and they agreed to accommodate us.
As part of the normal process of auditing a new factory, we took a number of pictures. Here are a few.
There were a number of Engineering Questions (EQ) that were raised that required us to carefully check the potential issues before providing a response on how the fabrication house should proceed. This is part of the process of getting PCBs manufactured. Since our board uses some complex technologies such as a few Wafer Level Chip Scale Packages (WLCSP) that have very fine ball spacing, we had to get the manufacturing tolerance correct to avoid issues during assembly. One issue we had is that their processes can’t accommodate white soldermask for the WLCSP component footprints. Their solution is to use a green soldermask around these components while the rest of the PCB will be white. This will not be the case for Mass Production as the fabrication house we use for M.P. has more advanced machinery capability of higher tolerance.The color white was chosen for the PCB so that it can reflect the keyboard backlight LEDs thereby making them appear brighter. If we had chosen a different soldermask color, the true color of the LEDs would not come through.
Our perseverance is paying off. We are getting a quick-turn around on the PCBs and will be doing assembly of five pieces this week.We will be sending another update shortly after we have had some time to test the PCBs and let you know the results.