BBC Micro:bit là gì?
The device is described as half the size of a credit card[9] and has an ARM Cortex-M0 processor, accelerometer and magnetometer sensors, Bluetooth and USB connectivity, a display consisting of 25 LEDs, two programmable buttons, and can be powered by either USB or an external battery pack.[2] The device inputs and outputs are through five ring connectors that form part of a larger 25-pin edge connector.
The physical board measures 43 mm × 52 mm and, as of the start of final manufacturing,[10] includes:
Nordic nRF51822 – 16 MHz 32-bit ARM Cortex-M0 microcontroller, 256 KB flash memory, 16 KB static ram, 2.4 GHz Bluetooth low energy wireless networking. The ARM core has the capability to switch between 16 MHz or 32.768 kHz.[2][3][11][12][13][14]
NXP/Freescale KL26Z – 48 MHz ARM Cortex-M0+ core microcontroller, that includes a full-speed USB 2.0 On-The-Go (OTG) controller, used as a communication interface between USB and main Nordic microcontroller. This device also performs the voltage regulation from the USB supply (4.5-5.25V) down to the nominal 3.3 volts used by the rest of the PCB. When running on batteries this regulator is not used.
NXP/Freescale MMA8652 – 3-axis accelerometer sensor via I²C-bus.[15]
NXP/Freescale MAG3110 – 3-axis magnetometer sensor via I²C-bus (to act as a compass and metal detector).[15]
MicroUSB connector, battery connector, 25-pin edge connector.[2][13][15][16]
Display consisting of 25 LEDs in a 5×5 array.[13]
Three tactile pushbuttons (two for user, one for reset).[17]
I/O includes three ring connectors (plus one power one ground) which accept crocodile clips or 4 mm banana plugs[17] as well as a 25-pin edge connector with two or three PWM outputs, six to 17 GPIO pins (depending on configuration), six analog inputs, serial I/O, SPI, and I²C.[15] Unlike early prototypes, which had an integral battery, an external battery pack (AAA batteries) can be used to power the device as a standalone or wearable product.[3][9][13] Health and safety concerns, as well as cost, were given as reasons for the removal of the button battery from early designs.[18]
The available hardware design documentation consist of only the schematic and BOM distributed under the Creative Commons By Attribution license, no PCB layout is available.[19][20] The compatible reference design by Micro:bit Educational Foundation, however, is fully documented.
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