This is a main control board for the Flex Modules. It is an STM32F401 which is the most compact M4 Cortex die available. We hope to eventually shrink the board further with support of the WLCSP 3x3mm package. There will be many versions of this board with a variety of pins routed depending on Fyber Labs project requirements.
To support USB, an external crystal is required. Clock timing through the STM32CubeMX code generating GUI are the following (left to right in UI/self explanatory):
24MHz crystal:
Input frequency = 24, PLL Source Mux = HSE, /M = /16, *N = x224,
/P = /4, /Q = /7, System Clock Mux = PLLCLK, AHB Prescaler = /1, APB1 Prescaler = /2.
16MHz crystal:
Input frequency = 16, PLL Source Mux = HSE, /M = /10, *N = x210,
/P = /4, /Q = /7, System Clock Mux = PLLCLK, AHB Prescaler = /1, APB1 Prescaler = /2.
8MHz is the development board (32F401CDiscovery) default, however they require a much larger footprint.
Programming is supported through SWD utilizing the 6-Pin Tag-Connect TC2030-IDC.
We have preliminary Espruino support. Web GUI interface through UART works for the chip, though USB device configuration is still not functional.
Any software related will be released under BSD or MIT license. SAAS or cloud based software will be AGPL.
Considering kickstarter it? I would buy!