Add code for mouse support in NeXT keyboard

CircuitPython_NeXT_Keyboard_RP2040/code.py

@@ -10,6 +10,7 @@ from keypad import Keys
 from adafruit_hid.consumer_control import ConsumerControl
 from adafruit_hid.keyboard import Keyboard
 from adafruit_hid.keyboard import Keycode
+from adafruit_hid.mouse import Mouse
 from adafruit_pioasm import Program
 from adafruit_ticks import ticks_add, ticks_less, ticks_ms
 from next_keycode import (
@@ -21,6 +22,14 @@ from next_keycode import (
     shift_modifiers,
 )
 
+
+# Compared to a modern mouse, the DPI of the NeXT mouse is low. Increasing this
+# number makes the pointer move further faster, but it also makes moves chunky.
+# Customize this number according to the trade-off you want, but also check
+# whether your operating system can assign a higher "sensitivity" or
+# "acceleration" for the mouse.
+MOUSE_SCALE = 8
+
 # Customize the power key's keycode. You can change it to `Keycode.POWER` if
 # you really want to accidentally power off your computer!
 POWER_KEY_SENDS = Keycode.F1
@@ -79,7 +88,8 @@ def set_leds(i):
     return pack_message_str(f"0000000001110{i:02b}0000000")
 
 
-QUERY = pack_message_str("000001000", 1)
+QUERY = pack_message_str("000001000", True)
+MOUSEQUERY = pack_message_str("010001000", True)
 RESET = pack_message_str("0111101111110000000000")
 
 BIT_BREAK = 1 << 11
@@ -94,12 +104,19 @@ def is_mod_report(report):
     return not bool(report & BIT_MOD)
 
 
+def extract_bits(report, *positions):
+    result = 0
+    for p in positions:
+        result = (result << 1)
+        if report & (1 << p):
+            result |= 1
+        #result = (result << 1) | bool(report & (1<<p))
+    return result
+
 # keycode bits are backwards compared to other information sources
 # (bit 0 is first)
 def keycode(report):
-    b = f"{report >> 12:07b}"
-    b = "".join(reversed(b))
-    return int(b, 2)
+    return extract_bits(report, 12, 13, 14, 15, 16, 17, 18)
 
 
 def modifiers(report):
@@ -122,11 +139,18 @@ sm = rp2pio.StateMachine(
 )
 
 
+def signfix(num, sign_pos):
+    """Fix a signed number if the bit with weight `sign_pos` is actually the sign bit"""
+    if num & sign_pos:
+        return num - 2*sign_pos
+    return num
+
 class KeyboardHandler:
     def __init__(self):
         self.old_modifiers = 0
         self.cc = ConsumerControl(usb_hid.devices)
         self.kbd = Keyboard(usb_hid.devices)
+        self.mouse = Mouse(usb_hid.devices)
 
     def set_key_state(self, key, state):
         if state:
@@ -144,6 +168,27 @@ class KeyboardHandler:
             else:
                 self.kbd.release(key)
 
+    def handle_mouse_report(self, report):
+        if report == 1536: # the "nothing happened" report
+            return
+
+        dx = extract_bits(report, 11,12,13,14,15,16,17)
+        dx = -signfix(dx, 64)
+        dy = extract_bits(report, 0,1,2,3,4,5,6)
+        dy = -signfix(dy, 64)
+        b1 = not extract_bits(report, 18)
+        b2 = not extract_bits(report, 7)
+
+        self.mouse.report[0] = (
+            Mouse.MIDDLE_BUTTON if (b1 and b2) else
+            Mouse.LEFT_BUTTON if b1 else
+            Mouse.RIGHT_BUTTON if b2
+            else 0)
+        if dx or dy:
+            self.mouse.move(dx * MOUSE_SCALE, dy * MOUSE_SCALE)
+        else:
+            self.mouse._send_no_move() # pylint: disable=protected-access
+
     def handle_report(self, report_value):
         if report_value == 1536: # the "nothing happened" report
             return
@@ -205,5 +250,19 @@ try:
             sm.restart()
             sm.write(RESET)
             time.sleep(0.1)
+
+        sm.write(MOUSEQUERY)
+        deadline = ticks_add(ticks_ms(), 100)
+        while ticks_less(ticks_ms(), deadline):
+            if sm.in_waiting:
+                sm.readinto(recv_buf)
+                value = recv_buf[0]
+                handler.handle_mouse_report(value)
+                break
+        else:
+            print("keyboard did not respond - resetting")
+            sm.restart()
+            sm.write(RESET)
+            time.sleep(0.1)
 finally:  # Release all keys before e.g., code is reloaded
     handler.kbd.release_all()