bridge

docs/pico_hid.md

@@ -1,4 +1,4 @@
-# Raspberry Pi Pico HID
+# The Pico HID
 
 The Pico HID is a part of [DIY PiKVM V1](v1.md) platform that performs keyboard and mouse emulation.
 It has excellent compatibility, and emulates USB by default, including two mouse modes: absolute and relative.
@@ -52,7 +52,7 @@ But if you are making the Pico HID for [V2](v2.md) or [V3](v3.md), then follow t
     Soldering skills will also come in handy.
 
     * *x1* 3.3V/5V bi-directional logic level shifter [like this](https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/).
-    * Optional: *x2* PS/2 cable with male connector (can be salvaged from the an keyboard or mouse).
+    * *x2* PS/2 cable with male connector (can be salvaged from the an keyboard or mouse).
 
     Make sure that the level shifter pinout matches the scheme, and connect everything according to the [Pico pinout](https://pico.pinout.xyz).
 
@@ -132,7 +132,7 @@ To upload the firmware to Pico HID, you can use any computer with a USB port.
 -----
 ## The final steps
 
-Connect the Pico HID to a computer using the USB cable.
+Connect the Pico HID to the target host using the USB cable.
 
 If you are building PiKVM [V1](v1.md), no further action with the Pico HID is required.
 

docs/pico_hid_bridge.md

@@ -0,0 +1,93 @@
+# The Pico HID PS/2 Bridge
+
+The Pico HID Bridge is a special case of the [Pico HID](pico_hid.md).
+It is a simple PS/2-only emulator with a USB interface. Unlike generic [Pico HID](pico_hid.md)
+and legacy [Arduino HID](arduino_hid.md), it doesn't require SPI wiring with GPIO.
+
+At one end it connects to USB-A on PiKVM, on the other side it has two PS/2 connectors for keyboard and mouse:
+
+<a href="pico_hid_bridge_ps2.jpg"><img src="pico_hid_bridge_ps2.jpg" width="500"/></a>
+
+In addition, on PiKVM V2+, the use of Pico the HID Bridge does not exclude the use of a regular USB OTG port with Mass Storage emulation.
+Thus, on V2+ you will be able to use PS/2 and USB Mass Storage at the same time, and even switch between OTG HID and [Pico HID](pico_hid.md).
+
+
+-----
+## Making the Bridge
+
+* *x1* [Raspberry Pi Pico board](https://www.raspberrypi.com/products/raspberry-pi-pico/) with soldered pins.
+* *x1* USB-A to Micro-USB cable.
+* *x1* 3.3V/5V bi-directional logic level shifter [like this](https://learn.sparkfun.com/tutorials/bi-directional-logic-level-converter-hookup-guide/).
+* *x2* PS/2 cable with male connector.
+* *x2* Small dip jumpers.
+
+Make sure that the level shifter pinout matches the scheme, and connect everything according to the [Pico pinout](https://pico.pinout.xyz).
+
+```
+				 _________________
+				|                 |
+Pico GP11 ______| LV1         HV1 |______ PS/2 keyboard data
+Pico GP12 ______| LV2         HV2 |______ PS/2 keyboard clock
+Pico GP13 ______| LV          HV  |______ PS/2 5V
+Pico  GND ______| GND         GND |______ PS/2 GND
+Pico GP14 ______| LV3         HV3 |______ PS/2 mouse data
+Pico GP15 ______| LV4         HV4 |______ PS/2 mouse clock
+				|_________________|
+
+```
+
+You can take the 5V power line from one of the PS/2, for example from the keyboard,
+or from both at once, but use a multimeter to make sure that both PS/2 female 
+connectors have the same line.
+
+<img src="../pico_hid/ps2_pinout.png" />
+
+PS/2 female socket pinout on the motherboard is the same for the keyboard and the mouse.
+A purple socket usually corresponds to the keyboard, and a green one to the mouse.
+If your motherboard only has one port, it's probably universal and can be used for both
+the keyboard and the mouse. Most likely, it will be painted both colors.
+
+Use a multimeter to determine the purpose of the wires in your PS/2 cables.
+
+A good idea is to mount the level shifter on top of the Pico, as in this photo:
+
+<img src="../pico_hid/ps2_level_shifter_soldering.png" width="300" />
+
+Finally, install DIP jumpers to soldered pins of the Pico to enable PS/2 and Bridge modes:
+
+* `GP2 <-> GND`
+* `GP5 <-> GND`
+
+Like this:
+
+<a href="pico_hid_bridge_ps2_jumpers.jpg"><img src="pico_hid_bridge_ps2_jumpers.jpg" width="500"/></a>
+
+
+-----
+## Flashing the firmware
+
+To upload the firmware to Pico HID, you can use any computer with a USB port.
+
+1. [Download](https://github.com/pikvm/kvmd/releases) the latest release of the firmware. The file is called `pico-hid.uf2`.
+2. Press and hold the white button on the Pico board.
+3. While still holding the button, plug it in the computer using a USB cable.
+4. Release the button.
+5. The Pico board appears as a flash drive on your computer.
+6. Copy the `pico-hid.uf2` file to this flash drive.
+7. Safely eject the USB device.
+
+
+-----
+## The final steps
+
+Connect the Pico HID to the target host using PS/2 cable and USB to USB-A port on PiKVM.
+
+Add following lines to the PiKVM configuration and reboot it:
+
+* `/etc/kvmd/override.yaml`:
+    ```yaml
+    kvmd:
+        hid:
+            type: serial
+			device: /dev/kvmd-hid-bridge
+    ```