usbd: Update hid_keypad example module.

- Use SET_REPORT via control transfer.
- Merge the keycodes module into hid_keypad.
- Remove LEDs other than NumLock to make the report handler even simpler.

Author: projectgus

micropython/usbd/hid_keypad.py

@@ -0,0 +1,96 @@
+# MicroPython USB keypad module
+# MIT license; Copyright (c) 2023 Dave Wickham, Angus Gratton
+
+from .hid import HIDInterface
+from micropython import const
+
+_INTERFACE_PROTOCOL_KEYBOARD = const(0x01)
+
+# See HID Usages and Descriptions 1.4, section 10 Keyboard/Keypad Page (0x07)
+#
+# This keypad example has a contiguous series of keys (KEYPAD_KEY_IDS) starting
+# from the NumLock/Clear keypad key (0x53), but you can send any Key IDs from
+# the table in the HID Usages specification.
+_KEYPAD_KEY_OFFS = const(0x53)
+
+_KEYPAD_KEY_IDS = [
+    "<NumLock>",
+    "/",
+    "*",
+    "-",
+    "+",
+    "<Enter>",
+    "1",
+    "2",
+    "3",
+    "4",
+    "5",
+    "6",
+    "7",
+    "8",
+    "9",
+    "0",
+    ".",
+]
+
+
+def _key_to_id(key):
+    # This is a little slower than making a dict for lookup, but uses
+    # less memory and O(n) can be fast enough when n is small.
+    return _KEYPAD_KEY_IDS.index(key) + _KEYPAD_KEY_OFFS
+
+
+# fmt: off
+_KEYPAD_REPORT_DESC = bytes(
+    [
+        0x05, 0x01,  # Usage Page (Generic Desktop)
+            0x09, 0x07,  # Usage (Keypad)
+            0xA1, 0x01,  # Collection (Application)
+                0x05, 0x07,  # Usage Page (Keypad)
+                    0x19, 0x00,  # Usage Minimum (0)
+                    0x29, 0xFF,  # Usage Maximum (ff)
+                    0x15, 0x00,  # Logical Minimum (0)
+                    0x25, 0xFF,  # Logical Maximum (ff)
+                    0x95, 0x01,  # Report Count (1),
+                    0x75, 0x08,  # Report Size (8),
+                    0x81, 0x00,  # Input (Data, Array, Absolute)
+                0x05, 0x08,  # Usage page (LEDs)
+                    0x19, 0x01,  # Usage Minimum (1)
+                    0x29, 0x01,  # Usage Maximum (1),
+                    0x95, 0x01,  # Report Count (1),
+                    0x75, 0x01,  # Report Size (1),
+                    0x91, 0x02,  # Output (Data, Variable, Absolute)
+                    0x95, 0x01,  # Report Count (1),
+                    0x75, 0x07,  # Report Size (7),
+                    0x91, 0x01,  # Output (Constant) - padding bits
+            0xC0,  # End Collection
+    ]
+)
+# fmt: on
+
+
+class KeypadInterface(HIDInterface):
+    # Very basic synchronous USB keypad HID interface
+
+    def __init__(self):
+        self.numlock = False
+        self.set_report_initialised = False
+        super().__init__(
+            _KEYPAD_REPORT_DESC,
+            set_report_buf=bytearray(1),
+            protocol=_INTERFACE_PROTOCOL_KEYBOARD,
+            interface_str="MicroPython Keypad",
+        )
+
+    def handle_set_report(self, report_data, _report_id, _report_type):
+        report = report_data[0]
+        b = bool(report & 1)
+        if b != self.numlock:
+            print("Numlock: ", b)
+            self.numlock = b
+
+    def send_key(self, key=None):
+        if key is None:
+            self.send_report(b"\x00")
+        else:
+            self.send_report(_key_to_id(key).to_bytes(1, "big"))