KiCad project: STM8L051F3P6 breakout w/ nRF24L01+
STM8L051F3P6 board with an nRF24L01+ module, a 32.768KHz crystal, and a CR2032 battery holder for prototyping wireless sensors. STM8 eForth support for nRF24L01+ (or SI24R1) is work in progress.
The HackaDay project STM8 eForth Wireless Sensor explores using this PCB.
PCB can be ordered from OSHPark (3pcs for about $4):