8.3 Brown-Out Mitigation Techniques for New Self-Hosted CC3200 Designs

This section describes how to mitigate the effects of a substantially discharged battery on a self-hosted CC3200 system. It is assumed that the CC3200 device is the main controller and has the ability to control all high power components in the system and that Service Pack [1.0.1.6] and SDK [1.2.0] or later have been installed.

The problem: The brownout problem can occur when operating with a substantially discharged battery which has enough energy to power up the CC3200 processor, but not enough to power the Wi-Fi transmitter. This can cause a loop where the CC3200 device powers up, reaches the point where it does some high power activity, this activity causes the battery voltage to drop below brown out threshold causing a reset. Once reset, the device consumes no power, the voltage rises back above brown out threshold and the device powers up again.

The solution: The suggested approach to avoid the above cycle is to use the secondary bootloader (like the one used in over-the-air updates) to load the user application and keep track of whether the application was loaded successfully (without causing another brown out event). This is done by keeping a counter in an on chip register (OCR) which will most likely be retained if voltage drops due to excessive power usage. The power up flow should be as described in the scheme below.