Manufacturing Test Accessories
When you design many boards (over 100, to date) you start to see common requirements. Most boards need a way to connect:
UART Serial Interface
There’s no easy way to accomplish this without adding a lot of connectors to the board, so we made our own small programming board. This connects to the target PCBA with one small connector. This connector is a spring loaded cable so no part is required on the target, only a PCB pattern.
This programming board has been used to program tens of thousands of devices because it is so versatile. It can interface with three types of processors:
TI 8051 (CC2530, CC2541, etc.)
ARM from multiple vendors
This programming board acts as a “breakout board” to convert from the 10 pin target connector to industry standard connectors.
ibeacon USB receiver
The Apple iBeacon standard defines a protocol for a Bluetooth Low Energy beacon. The standard is very straightforward so we use it in manufacturing testing to output test results. This information is then received with one of our custom iBeacon USB receivers. We made two versions of this - one that outputs the information via ASCII to a screen, and the other that outputs the information via binary. Both use a normal COM port for easy integration with other systems. While manufacturing test systems don’t need to use the iBeacon standard, it makes it much easier since these include the following fields:
UUID - 16 Bytes - basically the ‘name’ of the application; sometimes we include the device’s serial number
Major - 2 Bytes - can be used for anything; we frequently use it for self-test results
Minor - 2 Bytes - can be used for anything; we often use it for firmware version
TxPower - 1 Byte - officially this is the device’s output power at 1m but can be used for anything
The advantages of using this same packet format for test messages are:
Easy to implement - fixed width fields
Easy to troubleshoot - many view apps
Standard tools - we have two hardware tools to assist us
However, the downsides of using this standard for test information are:
Insecure - although you could encrypt your core data if you want
Only one way transmission from Device Under Test to our system
Now you may be wondering why the PCB in the USB Dongle is pink. We wanted to pick a color that stood out so it’s clear that this is a piece of test equipment, so we chose pink. And it looked cool.