New Pygmy Nebula Prototypes

The last revision of the Nebula was mostly a success. The one disappointment was the Microchip LiPo charging IC, it performed poorly and seemed somewhat unpredictable when load on the output was inadequate. This forced us to use LiPo batteries with all the prototypes, even when the application didn’t warrant the use of a battery. A redesign was put through to upgrade to a superior TI battery management IC.

Well, the latest PCBs have arrived, been assembled and tested! The TI part functions perfectly, it provides improved protection, a rock steady output and high current capability.

Another first was tested with the most recent proto PCBs: The first XL Density STM32F103s for the High Performance Nebula. These MCUs have 1MB of Flash, 96KB of RAM, and run at 72MHz. Initially, the bootloader failed to flash code into the XL devices. Errata notes and the updated programming manual show that the internal flash configuration changes at512KB to 2KB pages in the HD and XL and 2KB pages arranged in dual-bank configuration for the XL. This hardware change required a minor re-write of the bootloader, which I completed today. The bootloader was already capable of detecting the MCU ID and self configuring to adapt to hardware variations, the update leveraged that ability and new peripheral defines to extend compatibility to the XL line.


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