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Copy file name to clipboardexpand all lines: accessories/making-accessories.md
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### V2 revision
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The edge connector on the <spanclass="V2">V2</span> board revision is backwards compatible with the <spanclass="v1">v1</span> edge connector, but has additional dedicated pins.
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The edge connector on the <spanclass="V2">V2</span> board revision is backwards compatible with the <spanclass="v1">V1</span> edge connector, but has additional dedicated pins.
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- Details of the [edge connector and pinout](/hardware/edgeconnector)
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- Details about [powering things from the board](/hardware/powersupply)
The micro:bit has a <spanclass="v2">v2</span>Bluetooth 5.0/<spanclass="v1">v1</span>Bluetooth 4.1 stack with Bluetooth Low Energy (BLE) and supports the <spanclass="v1">v1</span>[GAP Peripheral Role](https://bluetooth-developer.blogspot.com/2016/07/microbit-and-bluetooth-roles.html) and <spanclass="v2">v2</span> GAP Peripheral and Central device roles.
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The micro:bit has a <spanclass="v2">V2</span>Bluetooth 5.0/<spanclass="v1">V1</span>Bluetooth 4.1 stack with Bluetooth Low Energy (BLE) and supports the <spanclass="v1">V1</span>[GAP Peripheral Role](https://bluetooth-developer.blogspot.com/2016/07/microbit-and-bluetooth-roles.html) and <spanclass="v2">V2</span> GAP Peripheral and Central device roles.
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It operates in the ISM (Industrial Scientific Medical) band, as per all Bluetooth devices. This starts at **2.4GHz and ends at 2.41GHz**. BLE divides the frequency band into 50 x 2MHz bands of which 40 are used. These are called **channels** and numbered **0 to 39**. Channels 37, 38 and 39 are used for "advertising".
Copy file name to clipboardexpand all lines: hardware/1-5-revision.md
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The compass must be calibrated before use, and the calibration process is automatically initiated by the runtime software.
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This device is connected to the application processor via the I2C bus.
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The v1.5 micro:bit has a footprint for two different motion sensors: one made by ST (the LSM303AGR) and one by NXP (FXOS8700CQ). The micro:bit DAL supports both of these sensors, detecting them at runtime. To date, all v1.5 boards have been manufactured with the LSM303AGR. If we were to move to the NXP part, a round of testing would be required and we would notify the [DAL and Devices mailing list.](http://eepurl.com/dyRx-v)
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The V1.5 micro:bit has a footprint for two different motion sensors: one made by ST (the LSM303AGR) and one by NXP (FXOS8700CQ). The micro:bit DAL supports both of these sensors, detecting them at runtime. To date, all V1.5 boards have been manufactured with the LSM303AGR. If we were to move to the NXP part, a round of testing would be required and we would notify the [DAL and Devices mailing list.](http://eepurl.com/dyRx-v)
This table shows various data about each of the pins on the micro:bit edge connector.
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NOTE 3: The pin marked 'ACCESSIBILITY' is used to enable/disable an on-board accessibility mode, and should not be used for anything else (even though it can be used as a GPIO for testing). Future versions of the official micro:bit editors may remove the ability to write to this pin.
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NOTE 4: The BBC suggest in the safety guide, that the maximum current you can draw from the whole edge connector at any one time is <spanclass="v1">v1</span>90mA. This is set based on the 30mA budget for on-board peripherals, and the fact that the on-board regulator of the KL26 when powered from USB is rated at a maximum of 120mA. On the latest board revision the maximum current is <spanclass="V2">V2</span>270mA, though it is possible that the on-board mic and speaker can draw more current, so this value is TBC.
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NOTE 4: The BBC suggest in the safety guide, that the maximum current you can draw from the whole edge connector at any one time is <spanclass="v1">V1</span>90mA. This is set based on the 30mA budget for on-board peripherals, and the fact that the on-board regulator of the KL26 when powered from USB is rated at a maximum of 120mA. On the latest board revision the maximum current is <spanclass="v2">V2</span>270mA, though it is possible that the on-board mic and speaker can draw more current, so this value is TBC.
Copy file name to clipboardexpand all lines: hardware/i2c-shared.md
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The motion sensors on the board are on the same I2C bus as the edge connector I2C pins. This means that if you have an accessory that uses I2C on this bus, you need to check it won’t clash with any of the possible on-board sensors. The [latest board revision does not share the I2C bus](../i2c/).
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The v1.5 micro:bit has a footprint for two different motion sensors: one made by ST (the LSM303AGR) and one by NXP (FXOS8700CQ). The micro:bit DAL supports both of these sensors, detecting them at runtime. To date, all v1.5 boards have been manufactured with the LSM303AGR, however we may switch to the NXP part. Before doing so we will perform a round of testing and notify the [DAL and Devices mailing list.](http://eepurl.com/dyRx-v)
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The V1.5 micro:bit has a footprint for two different motion sensors: one made by ST (the LSM303AGR) and one by NXP (FXOS8700CQ). The micro:bit DAL supports both of these sensors, detecting them at runtime. To date, all V1.5 boards have been manufactured with the LSM303AGR, however we may switch to the NXP part. Before doing so we will perform a round of testing and notify the [DAL and Devices mailing list.](http://eepurl.com/dyRx-v)
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### I2C block diagram
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Copy file name to clipboardexpand all lines: hardware/power-consumption.md
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## Power modes
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The micro:bitv2 <spanclass="v2">V2</span> board revision has a range of modes that enable us to conserve power, for example when the board is not being used or when it is powered by battery pack.
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The micro:bitV2 <spanclass="v2">V2</span> board revision has a range of modes that enable us to conserve power, for example when the board is not being used or when it is powered by battery pack.
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### Awake
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## LED display
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The LED display on the <spanclass="v2">V2</span> board revision is also brighter than previous revisions, so when using at full brightness you will notice faster battery drain than an equivalent program on a <spanclass="v1">v1</span> board.
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The LED display on the <spanclass="v2">V2</span> board revision is also brighter than previous revisions, so when using at full brightness you will notice faster battery drain than an equivalent program on a <spanclass="v1">V1</span> board.
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See our tips on [prolonging battery life](https://support.microbit.org/en/support/solutions/articles/19000087231-prolonging-battery-life)
Copy file name to clipboardexpand all lines: hardware/powersupply.md
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It's is important to stay within the design parameters of the board:
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- When powered from USB, the on-board interface chip (KL26<spanclass="v1">v1</span>/KL27<spanclass="v2">V2</span>) uses its on-chip regulator to provide power, and this chip is rated at a maximum of 120mA.
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- When powered from USB, the on-board interface chip (KL26<spanclass="v1">V1</span>/KL27<spanclass="v2">V2</span>) uses its on-chip regulator to provide power, and this chip is rated at a maximum of 120mA.
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- The on-board current budget will vary depending on the use of the display, the Bluetooth, microphone, speaker and other peripherals. You should allow a worst case budget of 30mA for when all on-board peripherals are in use, leaving <spanclass="v1">v1</span>90mA/<spanclass="v2">V2</span>270mA for circuits plugged into the edge connector.
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- The on-board current budget will vary depending on the use of the display, the Bluetooth, microphone, speaker and other peripherals. You should allow a worst case budget of 30mA for when all on-board peripherals are in use, leaving <spanclass="v1">V1</span>90mA/<spanclass="v2">V2</span>270mA for circuits plugged into the edge connector.
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- When powered from a battery, the KL chip is not powered up and the USB Indicator LED will not light up.
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As taken from each of the chip datasheets, it can be seen that different devices have slightly different operating voltage ranges and absolute maximum voltages. Manufacturers state the operating voltage range as well as the absolute maximum tolerable by the device. You should never exceed the operating voltage range of any of the devices.
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### v1 revision
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### V1 revision
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| Device | min | max | absolutemax
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<!-- TODO: Update these paragraphs to detail that 270mA is TBC budget for V2 -->
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When powered from USB, the KL26 <spanclass="v1">v1</span> interface chip's on-board regulator is used to provide 3.3V to the rest of the board. The latest revision <spanclass="v2">V2</span> has a seperate regulator on the board.
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When powered from USB, the KL26 <spanclass="v1">V1</span> interface chip's on-board regulator is used to provide 3.3V to the rest of the board. The latest revision <spanclass="v2">V2</span> has a seperate regulator on the board.
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The [KL26 datasheet](http://www.nxp.com/docs/pcn_attachments/16440_KL26P64M48SF5_Rev.4.pdf)<spanclass="v1">v1</span> section 3.8.2, Table 30. "USB VREG electrical specifications" indicates the maximum current from the regulated supply is 120mA. Some of this current is required to run on-board devices, such as the KL26 itself, the nRF application processor, the motion sensor, and the LED display. When Bluetooth is enabled, the current consumption of the nRF increases slightly. You should budget your current requirements for anything you attach to the micro:bit <spanclass="v1">v1</span> to not exceed about
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The [KL26 datasheet](http://www.nxp.com/docs/pcn_attachments/16440_KL26P64M48SF5_Rev.4.pdf)<spanclass="v1">V1</span> section 3.8.2, Table 30. "USB VREG electrical specifications" indicates the maximum current from the regulated supply is 120mA. Some of this current is required to run on-board devices, such as the KL26 itself, the nRF application processor, the motion sensor, and the LED display. When Bluetooth is enabled, the current consumption of the nRF increases slightly. You should budget your current requirements for anything you attach to the micro:bit <spanclass="v1">V1</span> to not exceed about
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90mA to give enough safe headroom for worst case with all on-board peripherals in use.
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This means that if you require more than 90mA from the edge connector, (e.g. driving lots of NeoPixels or a small motor) these should have power supplied to them externally. You can back-power the micro:bit via its 3V pad, but please be sure to use a properly regulated supply and a protection diode, as explained below, so that your micro:bit always has a supply within the operating range of all the on-board peripherals and the supplies are not able to power each other.
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2. If powered from a voltage source that could generate a voltage higher than the maximum operating voltage of the micro:bit, fit some form of over voltage protection, or proper regulation.
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### Power Supply Architecture v1
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### Power Supply Architecture V1
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The [schematic](/hardware/schematic/) shows the architecture of the power supply.
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Key points to note are that there are two BAT60A diodes, one from the 3.3V supply from the KL26/27 interface chip, and one from the external battery connector.
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### LEDS
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The LED matrix is physically laid out as a 5x5. On the <spanclass="v2">V2</span> board this is implemented as a 5x5 matrix, but in the <spanclass="v1">v1</span>, this is implemented as a scanned matrix of 9x3 (i.e. 9 columns by 3 rows). Row 2 Col 8, and Row 2 Col 9 are not used.
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The LED matrix is physically laid out as a 5x5. On the <spanclass="v2">V2</span> board this is implemented as a 5x5 matrix, but in the <spanclass="v1">V1</span>, this is implemented as a scanned matrix of 9x3 (i.e. 9 columns by 3 rows). Row 2 Col 8, and Row 2 Col 9 are not used.
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The LED matrix is driven via a high-speed multiplex generated by application processor software.
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This software also uses the LED Row and Col pins to implement the light sensing feature, as such you may see a difference in sensitivity between board revisions.
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Some of the Columns appear on the edge connector, so if you want to use extra GPIO pins, you have to disable the display in software.
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### Interface
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The Interface sheet shows the KL26/<spanclass="v1">v1</span>KL27<spanclass="v2">v2</span> processor, which is an NXP microcontroller with an Arm processor, that implements the USB protocol for the USB connector. This provides a method for loading code onto the application processor, using a drag and drop interface.
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The Interface sheet shows the KL26/<spanclass="v1">V1</span>KL27<spanclass="v2">V2</span> processor, which is an NXP microcontroller with an Arm processor, that implements the USB protocol for the USB connector. This provides a method for loading code onto the application processor, using a drag and drop interface.
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The USB protocol handler on this processor implements a Mass Storage Class device in order to offer the drag and drop code load interface. It also provides a Connected Device Class that allows a serial port interface to be used across the USB.
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The interface processor also contains an on-board regulator that steps down the USB voltage to 3.3V suitable for powering the rest of the micro:bit, and you can draw 120mA<spanclass="v1">v1</span>/300mA<spanclass="v2">V2</span> from this processor regulator. A TVS device is fitted to suppress ESD spikes and out of range voltages that could be present on the USB connector.
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The interface processor also contains an on-board regulator that steps down the USB voltage to 3.3V suitable for powering the rest of the micro:bit, and you can draw 120mA<spanclass="v1">V1</span>/300mA<spanclass="v2">V2</span> from this processor regulator. A TVS device is fitted to suppress ESD spikes and out of range voltages that could be present on the USB connector.
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This processor does not have any connection to the GPIO pins on the micro:bit.
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### Sensors
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There is one combined motion sensor IC on the micro:bit, that contains an accelerometer and a magnetometer. The accelerometer measures acceleration in 3 axes, and the magnetometer can be used as a compass, as well as a magnetic field detector.
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The device is connected to the application processor [I2C bus](../i2c/), and for the <spanclass="v1">v1</span> revision this [I2C bus is also shared](../i2c-shared/) to two pins on the edge connector. I2C pull-up resistors are pre-fitted on the board.
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The device is connected to the application processor [I2C bus](../i2c/), and for the <spanclass="v1">V1</span> revision this [I2C bus is also shared](../i2c-shared/) to two pins on the edge connector. I2C pull-up resistors are pre-fitted on the board.
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The magnetometer can generate one processor interrupt for the application processor, and the accelerometer can generate two different processor interrupts for the application processor.
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