Info for COMBINED_SENSOR_INT and logo pin (#269)

* Schematic page: Add logo pin.

* Add info about COMBINED_SENSOR_INT.

Author: microbit-carlos

hardware/i2c.md

@@ -49,4 +49,4 @@ No difference was seen between the revisions.
 
 ## Notes
 
-The <span class="v2">V2</span> device can be woken by activating the combined sensor interrupt on P0.25. This signal is connected between the nRF52, the KL27, and motion sensors and requires the nRF52 internal pull up to be configured, even while the device is sleeping.
+The <span class="v2">V2</span> device can be woken by activating (by pulling low) the combined sensor interrupt on P0.25. This open drain signal is connected between the nRF52, the KL27, and motion sensors and requires the nRF52 internal pull up to be configured, even while the device is sleeping.

hardware/schematic.md

@@ -47,6 +47,7 @@ Whilst we work on the publication of the schematic for the latest revision, here
 | P0.19            | ROW5                | N                                        |                     |
 | P0.14            | BTN_A               | N                                        | P5                  |
 | P0.23            | BTN_B               | N                                        | P11                 |
+| P1.04            | FACE_TOUCH          | N                                        |                     |
 | P0.16            | I2C_INT_SDA         | P23 (I2C1_SDA)                           |                     |
 | P0.17            | SCK_EXTERNAL        | N                                        | P13                 |
 | P0.01            | MISO_EXTERNAL       | N                                        | P14                 |
@@ -78,7 +79,7 @@ Some of the Columns appear on the edge connector, so if you want to use extra GP
 
 ### Interface
 
-The Interface sheet shows the KL26/<span class="v1">V1</span>KL27<span class="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.
+The Interface sheet shows the KL26<span class="v1">V1</span>/KL27<span class="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.
 
 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.
 
@@ -92,7 +93,9 @@ There is one combined motion sensor IC on the micro:bit, that contains an accele
 
 The device is connected to the application processor [I2C bus](../i2c/), and for the <span class="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.
 
-The magnetometer can generate one processor interrupt for the application processor, and the accelerometer can generate two different processor interrupts for the application processor.
+In <span class="v2">V2</span> there is a combined open drain, active low, interrupt signal (`COMBINED_SENSOR_INT`) to the application processor for the motion sensors and the KL27. Any device can asset this signal and the application processor has to query the individual devices to locate the origin.
+
+The magnetometer can generate one processor interrupt for the application processor, and the accelerometer can generate two different processor interrupts in <span class="v1">V1</span> or just one in <span class="v2">V2</span>.
 
 Note, the physical orientation of this IC is important for binary compatibility with the driver code in the application processor, which assumes a particular physical orientation in its calculations.
 
@@ -126,7 +129,7 @@ The edge connector is the main interface to external components attached to the
 
 This interface has a range of digital, analog, touch, PWM, and serial communications interfaces.
 
-10Mohm weak pull-up resistors are fitted on P0 P1 and P2 for use in touch sensing mode, where they provide a weak pull-up to the supply providing a default high input and the user touching the GND pad pulls the pin down towards 0V, providing a low input. When in non touch modes, these pads have stronger internal pull-downs enabled in the software, so that the default input state when not connected is 'low'.
+10Mohm weak pull-up resistors are fitted on P0 P1 P2 and logo<span class="v2">V2</span> for use in touch sensing mode, where they provide a weak pull-up to the supply providing a default high input and the user touching the GND pad pulls the pin down towards 0V, providing a low input. When in non touch modes, these pads have stronger internal pull-downs enabled in the software, so that the default input state when not connected is 'low'.
 
 Guard pins are provided both sides of the 3V and GND pads, so that shorting by crocodile clips does not degrade the features of the device by causing spurious inputs.