RedBearLab has launched the Blend Micro, a mini development board targeted at the Internet of Things (IoT). Powered by Atmel’s popular ATmega32u4 microcontroller (MCU), the board is also equipped with a Bluetooth 4.0 Smart Energy chip.
Blend Micro is compatible with Nordic’s Bluetooth Smart SDK for Arduino, making software development easy via the official Arduino IDE.
So, how does the board work? According to the RedBearLab crew, the nRF8001 chip communicates with Atmel’s Atmega32u4 MCU via the ACI (Application Controller Interface). Although the ACI is similar to SPI, it does not actually function as SPI. Indeed, SPI consists of MOSI, MISO, SCK and SS, whereas ACI includes MOSI, MISO, SCK, REQN and RDYN.
“Since the nRF8001 chip may receive data anytime (even when not selected by SPI master) the SS line is not needed. For the ACI, data exchange [is routed] through MOSI and MISO, [while] SCK provides the clock generated by master,” a RedBearLab rep explained.
“When the master wants to request data from BLE Shield, it [shifts] the REQN to low until RDYN line is put to low by BLE Shield. The master then generates the clock to read out the data. After reading out the data, master will release the REQN and BLE Shield release the RDYN, putting them to high.”
The Blend Micro runs at 3.3V to reduce level shifting, since the nRF8001 chip only accepts 3.3V. As such, the onboard LDO converts 5V from the USB power source into 3.3V for the board.
“Normally, you should set Blend Micro to run at 8 MHz/3.3V. However, if you want to run faster and not concern about the reliability (we do not see any issue so far), you can run it as 16 MHz [for a] so-called ‘overclock,’ the rep added.
Interested in learning more? You can check out Blend Micro’s official page here.