We have an exciting update for you and have a lot of developments to share with you. We thank you all for waiting so patiently.
While everything is returning back to normal here in China, we are watching closely to the ongoing situation regarding COVID-19 around the world. While we are safe, we hope that you and your loved ones are safe at home during this time.
Life in Shenzhen, China has slowly returned to where they were before but everyone is making sure to take extra precautions. This means that we are able to visit our factory partners, in person again, which is critical to ensure that everyone is on the same page and there is a clear understanding of our requirements for Pocket P.C. (We will be sharing photos and videos from a LCD display factory in our next post.)
Now on to the latest Pocket P.C. developments.
The schematics and layout for our Design Verification Test (D.V.T.) production run are complete. Allwinner, who makes the A64 processor and LPDDR3 RAM that we use in Pocket P.C., has performed a final review and made note of some changes that we will incorporate into the design early next week. After we have spent a few additional days reviewing the design, we will send the PCB Gerber files out for fabrication and we will then assemble them immediately after receiving them back from the PCB factory.
Note: D.V.T. is the step before Process Validation Test (P.V.T.) which is the final step before Mass Production (M.P.) in the product development life-cycle. If there are no issues with the manufacturing process then we can proceed producing many more.
Anyway, let’s dive right into the latest design!
The 3D render above is of the back-side of the PCB. There are 550 components on the PCB in total. There are some changes from the original specifications so let’s discuss them.
- We added an HDMI connector which can be seen on the top left of the PCB. With the display and keyboard facing you, the connector will be on the top right of Pocket P.C.
- We added a DisplayPort converter IC. This enables DisplayPort Alternate Mode (DP Alt Mode) over USB-C allowing you to connect directly to a monitor.
- Note: Only one of the external display connections will be able to be used at a time.
- We chose a RAKwireless 4200 LoRa module. (Seen in the upper right side of the PCB.) We had a lot of issues communicating with Murata and decided to look for a compatible module elsewhere. RAKwireless is a leader in LoRa solutions and are a 30 minute subway ride away from us, in Shenzhen, if we ever need to discuss something in person. Since the module has the same technical specifications as the Murata module, there is no disadvantage selecting the RAKwireless module for Pocket P.C.
- The SD card connector has changed styles from an internal card to one that is accessible from the side of the case. Now you will be able to easily change SD cards without needing to remove the back of the case.
- We added an internal back-up battery for the real-time clock in the keyboard controller which has evolved from it’s original purpose and is now more of a system management controller. The O.S. will now be able to poll this device on boot to set it’s internal clock.
The 3D render above is of the front-side of the PCB. While there are not too many components on this side of the board, you can see the heart of the keyboard controller right in the center. You may be wondering why there is another component next to it that looks exactly like it. Well, that’s new in this revision so let’s discuss it.
- We added an additional STM32 microcontroller that is identical to the keyboard controller except it will run different firmware. The purpose of this microcontroller is to provide a built in programming/debugging solution for the keyboard controller and the STM32 microcontroller in the RAKWireless LoRa module. (More about this in a future post.)
- We heard your early feedback about arrow keys and add four more buttons in the top right of the keyboard. These weren’t present on our original renders and we haven’t mentioned too much about the keyboard layout so far so we want to let you know that your feedback is important to us and has a real effect on what we do. (We will have a dedicated post on the keyboard in the next few weeks.)
- There are now three status LEDs on the upper left side of the keyboard. One LED is connected to the Power Management Unit (PMU) which let’s us know about the charging state of the battery. The other two will be connected to the system management controller and can be user configurable for whatever purpose.
The 3D render above shows the RGB LEDs lit green and the LCD display. Our original plan was to use Google Nexus 5 cellphone displays and connect them to the PCB on the front side but after feedback from our mechanical designer and production factory, they advised us that it is easier for assembly to connect the display on the back of the PCB. We created a notch in the main PCB for the LCD connector to wrap around.
You can see where the LCD display’s flexible printed circuit (FPC) connects to the PCB on the top right side in the render above. (The orange color part.) Due to this change in the way the LCD connects to the main circuit board, we will need to have a custom display made.
In our next post, we will be giving you an inside look into the LCD display factories here in Shenzhen.
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We have a lot to share with you soon. Until then stay safe and stay healthy!