Black Pill
The Black Pill development board is a good choice. Of the commercially available development modules, this is one of the best. It was designed by WeAct Studio, but like the Blue Pill many different versions exist. Unlike the Blue Pill, at least at the time of writing this, they all appear to be using genuine STM32 processors (read: no cheaper clones exist). Here are two different ones, both of which I suspect are clones (and both working just fine):
Features
The Black Pills are typically based on a STM32F401 or STM32F411 (both of the above are the F411 version) and offers the following specs:
- STM32F4 (STM32F401 or STM32F411) processor
- Same footprint (I/O pins)
- 25 MHz main crystal
- 32.768 kHz RTC crystal
- 512 kB Flash (STM32F411 version)
- 128 kB RAM
- 1 ADC (no DAC)
- USB-C connector
- Programming header
Pinout
Flash Layout
EEPROM Footprint
The Black Pill board usually have an unpopulated footprint on the reverse side of the PCB intended for a generic EEPROM:
On the Board Info page, this is documented as:
Unfortunately, the clone Black Pill boards are wired up different. The DO (MISO) is not wired up to PB4 as indicated but rather PA6 (which makes more sense anyway). Using STM32CubeMX, the right configuration is:
USB
The STM32F411 MCU on the Black Pill boards can in principle run in USB Host mode. However, it is worth having a look at the schematics:
Both the CC lines are pulled to GND using a 5.1k resistor, which signals that this is a device, not a host. Also, there is no way to control the power delivery. In short, while the MCU on these boards can operate in USB Host mode, there is no way this can be reliably done on the Black Pill boards.
Miscellaneous Links
- WeAct Black Pill Github Repository
- Board Info
- Original Schematics ver. 2.0
- Original Schematics vers. 1.2
- STM32F411x Datasheet
- STM32F411xC/E advanced Arm®-based 32-bit MCUs Reference Manual
- Bare metal coding on the STM32F411/Black Pill
Notice, most - if not all - clone boards match the 1.2 schematics.