rp2/PICO_COMPUTER_3: add USB mass-storage host (machine.USBDrive)

ports/rp2/CMakeLists.txt

@@ -244,6 +244,8 @@ if(MICROPY_HW_USB_HOST)
         usb_gamepad_mod.c
         usb_cdc.c
         usb_cdc_mod.c
+        usb_msc.c
+        machine_usbdrive.c
     )
 endif()
 
@@ -298,6 +300,7 @@ if(MICROPY_HW_USB_HOST)
         ${MICROPY_PORT_DIR}/usb_mouse_mod.c
         ${MICROPY_PORT_DIR}/usb_gamepad_mod.c
         ${MICROPY_PORT_DIR}/usb_cdc_mod.c
+        ${MICROPY_PORT_DIR}/machine_usbdrive.c
     )
 endif()
 if(MICROPY_HW_ENABLE_XMODEM)
@@ -479,6 +482,66 @@ if (MICROPY_BLUETOOTH_BTSTACK)
     list(APPEND MICROPY_INC_CORE ${BTSTACK_INCLUDE})
 endif()
 
+# Bluetooth Classic A2DP source (stream audio out to a Bluetooth speaker),
+# the `btaudio` module. Adds just the classic-profile BTstack sources this
+# needs (a2dp/avdtp source role + SDP + the SBC encoder) directly to the
+# firmware target, rather than linking pico-sdk's pico_btstack_classic
+# library -- that would pull in its own copy of hci.c/l2cap.c, duplicating
+# the ones micropy_extmod_btstack above already compiles for BLE. Classic and
+# LE share ONE BTstack/HCI instance (that's the whole point of dual-mode) --
+# hci.c/l2cap.c just need ENABLE_CLASSIC=1 applied to their one compilation,
+# which target_compile_definitions on the firmware target itself achieves
+# (it applies to every source pulled into this target, including
+# micropy_extmod_btstack's INTERFACE sources).
+if (MICROPY_HW_ENABLE_BT_A2DP)
+    if (NOT MICROPY_BLUETOOTH_BTSTACK)
+        message(FATAL_ERROR "MICROPY_HW_ENABLE_BT_A2DP requires MICROPY_BLUETOOTH_BTSTACK")
+    endif()
+
+    list(APPEND MICROPY_SOURCE_PORT
+        btaudio.c
+        ${BTSTACK_LIB_DIR}/src/classic/a2dp.c
+        ${BTSTACK_LIB_DIR}/src/classic/a2dp_source.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp_acceptor.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp_initiator.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp_source.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp_util.c
+        ${BTSTACK_LIB_DIR}/src/classic/sdp_client.c
+        ${BTSTACK_LIB_DIR}/src/classic/sdp_server.c
+        ${BTSTACK_LIB_DIR}/src/classic/sdp_util.c
+        ${BTSTACK_LIB_DIR}/src/classic/btstack_sbc_encoder_bluedroid.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_analysis.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_dct.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_dct_coeffs.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_enc_bit_alloc_mono.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_enc_bit_alloc_ste.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_enc_coeffs.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_encoder.c
+        ${BTSTACK_LIB_DIR}/3rd-party/bluedroid/encoder/srce/sbc_packing.c
+    )
+    list(APPEND MICROPY_SOURCE_QSTR ${MICROPY_PORT_DIR}/btaudio.c)
+
+    target_compile_definitions(${MICROPY_TARGET} PRIVATE
+        MICROPY_HW_ENABLE_BT_A2DP=1
+        ENABLE_CLASSIC=1
+    )
+    # Quiets known-noisy but harmless warnings in this vendored code (same
+    # suppressions pico-sdk's own pico_btstack_classic target applies).
+    set_source_files_properties(
+        ${BTSTACK_LIB_DIR}/src/classic/a2dp.c
+        ${BTSTACK_LIB_DIR}/src/classic/a2dp_source.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp.c
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp_source.c
+        ${BTSTACK_LIB_DIR}/src/classic/sdp_server.c
+        PROPERTIES COMPILE_OPTIONS "-Wno-cast-qual"
+    )
+    set_source_files_properties(
+        ${BTSTACK_LIB_DIR}/src/classic/avdtp_util.c
+        PROPERTIES COMPILE_OPTIONS "-Wno-unused-parameter"
+    )
+endif()
+
 if(MICROPY_BLUETOOTH_NIMBLE)
     list(APPEND GIT_SUBMODULES lib/mynewt-nimble)
     if(NOT UPDATE_SUBMODULES AND NOT EXISTS ${MICROPY_DIR}/lib/mynewt-nimble/nimble/host/include/host/ble_hs.h)

ports/rp2/boards/PICO_COMPUTER_3/USER_MANUAL.md

@@ -52,7 +52,7 @@ over the artwork otherwise) and restore `console()` in a `finally:`. XMODEM
 transfers use the serial port directly and work in any mode.
 
 The USB device port is disabled (there is no USB-CDC prompt); the USB port is a
-**host** port for keyboards, mice and touch panels.
+**host** port for keyboards, mice, touch panels and USB flash drives.
 
 At the prompt you can type Python directly, or use the shell-style helpers
 (section 4). To run a program from the SD card or flash:
@@ -94,7 +94,7 @@ cannot be claimed with `machine.Pin()`.
 | PSRAM chip-select | **GP47** | 8 MB PSRAM |
 | Wi-Fi / Bluetooth (CYW43) | REG_ON **GP23**, DATA **GP24**, CS **GP25**, CLK **GP29** | wireless chip over PIO-SPI — *reserved* |
 | Status LED | CYW43 **GPIO0** | on the wireless chip (not an RP2350 pin) — named pin `"LED"` |
-| USB host | native USB port | keyboard / mouse / touch |
+| USB host | native USB port | keyboard / mouse / touch / flash drive |
 
 The **status LED** is on the CYW43 wireless chip, not on an RP2350 GPIO. It is
 exposed as the named pin `"LED"` (an "extended" pin) and driven like any output —
@@ -166,6 +166,7 @@ MicroPython v1.29.0 on PICO COMPUTER 2 v0.16 with RP2350B
 - **Floats:** double precision (64-bit). Integers are arbitrary precision.
 - **Flash filesystem:** 12 MB LittleFS mounted at `/`.
 - **SD card:** FAT, mounted at `/sd`, hot-swappable (section 12).
+- **USB flash drive:** FAT, mounted at `/usb`, hot-pluggable (section 12).
 - **PSRAM:** 8 MB — the Python heap lives here, so large data/images/audio
   buffers are fine.
 
@@ -1538,6 +1539,16 @@ ls("/sd")
 f = open("/sd/data.txt", "w"); f.write("hello"); f.close()
 ```
 
+A USB flash drive works the same way, mounted at **`/usb`**: plug one into the
+host port and it appears (`USB drive mounted at /usb`); unplugging it unmounts
+it (`Warning: USB drive removed`). Unlike the SD card, no polling is
+involved — USB tells the board directly when a drive appears or disappears.
+
+```python
+ls("/usb")
+cp("/usb/prog.py", "/sd")
+```
+
 ---
 
 ## 13. File transfer (XMODEM)

ports/rp2/boards/PICO_COMPUTER_3/_boot_board.py

@@ -52,6 +52,12 @@
 
 pcsd.start()
 
+# USB flash drive: mount /usb (if one is already plugged in) and react to
+# further plug/unplug events -- see pcusb.py for why this needs no poll.
+import pcusb
+
+pcusb.start()
+
 # On-screen console: console() mirrors REPL output to the HDMI screen.
 import pcconsole
 

ports/rp2/boards/PICO_COMPUTER_3/manifest.py

@@ -19,6 +19,18 @@
 # runs the hot-swap removal/insertion poll (replicates MMBasic's CheckSDCard).
 freeze("$(BOARD_DIR)", "pcsd.py")
 
+# USB flash drive support is provided by the native C machine.USBDrive driver
+# (machine_usbdrive.c / usb_msc.c). pcusb.py mounts /usb and reacts to
+# USBDrive.on_change -- USB enumeration gives a definitive plug/unplug event,
+# so unlike pcsd.py this needs no poll.
+freeze("$(BOARD_DIR)", "pcusb.py")
+
+# BLE keyboard/mouse (HID over GATT) support -- scan/pair/connect on demand
+# (unlike pcsd.py/pcusb.py, this doesn't auto-start at boot: pairing is a
+# deliberate user action). Feeds reports into keyboard.inject_report() /
+# mouse.inject_report(), the same decoders USB keyboards/mice use.
+freeze("$(BOARD_DIR)", "pcblekbd.py")
+
 # Shell-style REPL helpers (ls, ...), injected into __main__ by _boot.py.
 freeze("$(BOARD_DIR)", "pcshell.py")
 

ports/rp2/boards/PICO_COMPUTER_3/mpconfigboard.cmake

@@ -48,6 +48,11 @@ set(MICROPY_PY_NETWORK_CYW43 ON)
 set(MICROPY_PY_BLUETOOTH ON)
 set(MICROPY_BLUETOOTH_BTSTACK ON)
 set(MICROPY_PY_BLUETOOTH_CYW43 ON)
+# Classic Bluetooth A2DP source (stream audio out to a Bluetooth speaker),
+# the `btaudio` module -- see CMakeLists.txt for why this needs ENABLE_CLASSIC
+# on the shared BTstack/HCI instance rather than pico-sdk's separate
+# pico_btstack_classic library.
+set(MICROPY_HW_ENABLE_BT_A2DP 1)
 
 # Pull in ulab (numpy-like ndarray/linalg) as a user C module for this board.
 # ulab's own micropython.cmake defines MODULE_ULAB_ENABLED and links itself into