variants: add nano rp2040 connect

boards.txt

@@ -660,4 +660,71 @@ unoq.bootloader.tool.default=remoteocd
 unoq.bootloader.file=zephyr-{build.variant}.elf
 unoq.bootloader.target=stm32u585zitxq
 
-##########################################################################################
+##############################################################################################################
+
+nano_connect.name=Arduino Nano RP2040 Connect
+nano_connect.build.core=arduino
+nano_connect.build.crossprefix=arm-zephyr-eabi-
+nano_connect.build.compiler_path={runtime.tools.arm-zephyr-eabi-0.16.8.path}/bin/
+
+nano_connect.menu.debug.false=Standard
+nano_connect.menu.debug.true=Debug
+nano_connect.menu.debug.true.build.zsk_args.debug=-debug
+
+nano_connect.menu.link_mode.dynamic=Dynamic
+nano_connect.menu.link_mode.static=Static
+nano_connect.menu.link_mode.static.build.link_mode=static
+nano_connect.menu.link_mode.static.upload.extension=bin-zsk.bin
+
+nano_connect.build.zephyr_target=arduino_nano_connect
+nano_connect.build.zephyr_args=
+nano_connect.build.zephyr_hals=hal_rpi_pico
+nano_connect.build.artifact=zephyr_main
+nano_connect.build.variant=arduino_nano_connect_rp2040
+nano_connect.build.mcu=cortex-m0plus
+nano_connect.build.fpu=
+nano_connect.build.architecture=cortex-m0plus
+nano_connect.compiler.zephyr.arch.define=
+
+nano_connect.build.float-abi=-mfloat-abi=soft
+nano_connect.build.extra_flags=
+nano_connect.build.postbuild.cmd="{tools.imgtool.path}/{tools.imgtool.cmd}" exit
+nano_connect.recipe.hooks.objcopy.postobjcopy.3.pattern="{runtime.tools.bin2uf2.path}/bin2uf2" {upload.address} {upload.familyid} "{build.path}/{build.project_name}.{upload.extension}" "{build.path}/{build.project_name}.uf2"
+nano_connect.build.board=NANO_RP2040_CONNECT
+nano_connect.compiler.zephyr=
+nano_connect.vid.0=0x2341
+nano_connect.pid.0=0x005E
+nano_connect.upload_port.0.vid=0x2341
+nano_connect.upload_port.0.pid=0x005E
+
+nano_connect.upload.tool=picotool
+nano_connect.upload.tool.default=picotool
+nano_connect.upload.protocol=
+nano_connect.upload.transport=
+nano_connect.upload.vid=0x2341
+nano_connect.upload.pid=0x005E
+nano_connect.upload.interface=0
+nano_connect.upload.use_1200bps_touch=true
+nano_connect.upload.wait_for_upload_port=false
+nano_connect.upload.native_usb=true
+nano_connect.upload.maximum_size=16777216
+nano_connect.upload.maximum_data_size=270336
+
+nano_connect.upload.address=0x100E0000
+nano_connect.upload.familyid=0xe48bff56
+
+nano_connect.bootloader.tool=picotool
+nano_connect.bootloader.tool.default=picotool
+nano_connect.bootloader.vid=0x2341
+nano_connect.bootloader.pid=0x005E
+nano_connect.bootloader.interface=0
+nano_connect.bootloader.file=zephyr-{build.variant}
+
+nano_connect.debug.tool=gdb
+nano_connect.debug.server.openocd.scripts.0=interface/{programmer.protocol}.cfg
+nano_connect.debug.server.openocd.scripts.1={programmer.transport_script}
+nano_connect.debug.server.openocd.scripts.2=target/rp2040-core0.cfg
+nano_connect.debug.cortex-debug.custom.request=attach
+nano_connect.debug.svd_file={runtime.platform.path}/svd/rp2040.svd
+
+##############################################################################################################

cores/arduino/llext_wrappers.c

@@ -74,13 +74,28 @@
  * The naked trampoline uses r12 (ip, AAPCS inter-procedure scratch register)
  * which is never an argument register, so r0–r3 and d0–d7 are untouched.
  */
+#if defined(__ARM_ARCH_6M__) || (defined(__ARM_ARCH) && __ARM_ARCH < 7)
+/* Thumb-1 (Cortex-M0/M0+): movw/movt are Thumb-2 only, use a PC-relative
+ * literal pool load via r4 (callee-saved, push/pop balanced). r0-r3 carry
+ * the RTABI double arguments and must not be touched.
+ */
+#define VN(name)                                                                                   \
+	__attribute__((naked)) void name(void) {                                                       \
+		__asm__("push {r4}\n\t"                                                                    \
+				"ldr  r4, =__real_" #name "\n\t"                                                   \
+				"mov  r12, r4\n\t"                                                                 \
+				"pop  {r4}\n\t"                                                                    \
+				"bx   r12");                                                                       \
+	}
+#else
 #define VN(name)                                                                                   \
 	__attribute__((naked)) void name(void) {                                                       \
 		__asm__("movw r12, #:lower16:__real_" #name "\n\t"                                         \
 				"movt r12, #:upper16:__real_" #name "\n\t"                                         \
 				"bx   r12");                                                                       \
 	}
 #endif
+#endif
 
 /* string.h */
 W3(void *, memcpy, void *, const void *, size_t)
@@ -203,6 +218,16 @@ VN(__aeabi_idivmod)
 VN(__aeabi_uidivmod)
 VN(__aeabi_ldivmod)
 VN(__aeabi_uldivmod)
+#if defined(__ARM_ARCH_6M__) || (defined(__ARM_ARCH) && __ARM_ARCH < 7)
+/*
+ * Thumb1 switch-dispatch helpers.
+ */
+VN(__gnu_thumb1_case_uqi)
+VN(__gnu_thumb1_case_sqi)
+VN(__gnu_thumb1_case_uhi)
+VN(__gnu_thumb1_case_shi)
+VN(__gnu_thumb1_case_si)
+#endif
 #endif
 
 /* stdio.h */

extra/build.sh

@@ -100,7 +100,7 @@ line_continuation='\\$' # match lines ending with '\'
 c_comment='\s*\/\*.*?\*\/' # match C-style comments and any preceding space
 perl -i -pe "s/${c_comment}//gs unless /${line_preproc_ok}/ || (/${line_comment_only}/ && !/${line_continuation}/)" $(find ${VARIANT_DIR}/llext-edk/include/ -type f)
 
-for ext in elf bin hex; do
+for ext in elf bin hex uf2; do
     rm -f firmwares/zephyr-$variant.$ext
     if [ -f ${BUILD_DIR}/zephyr/zephyr.$ext ]; then
         cp ${BUILD_DIR}/zephyr/zephyr.$ext firmwares/zephyr-$variant.$ext

libraries/SPI/SPI.cpp

@@ -114,11 +114,18 @@ void arduino::ZephyrSPI::detachInterrupt() {
 }
 
 void arduino::ZephyrSPI::begin() {
-
+#if defined(CONFIG_BOARD_ARDUINO_NANO_CONNECT)
+	/* On nano_connect the SPI driver is already initialized by the loader;
+	 * calling init() again on an already-ready device hangs. */
+	if (!device_is_ready(spi_dev)) {
+		(void)zephyr::arduino::init_dev_apply_pinctrl(spi_dev);
+	}
+#else
 	/* Re-apply DEFAULT pinctrl state so shared pins
 	 * are remuxed back to SPI after other peripherals have used them.
 	 */
 	(void)zephyr::arduino::init_dev_apply_pinctrl(spi_dev);
+#endif
 }
 
 void arduino::ZephyrSPI::end() {

loader/fixups.c

@@ -53,6 +53,54 @@ SYS_INIT(disable_bootloader_mpu, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAU
 SYS_INIT(disable_mpu_rasr_xn, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
 #endif
 
+#if defined(CONFIG_BOARD_ARDUINO_NANO_CONNECT)
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/gpio.h>
+#include <pico/bootrom.h>
+
+/*
+ * Double-tap reset detection: if the board is reset twice within 500ms,
+ * enter USB bootloader (BOOTSEL) mode. This mirrors the original
+ * ArduinoCore-mbed NANO_RP2040_CONNECT behavior.
+ *
+ * A magic token is stored in uninitialized RAM (.noinit), which survives
+ * a warm reset but is lost on power cycle. On boot:
+ *   - If the token is present: a second reset happened quickly, so we
+ *     clear the token and enter USB boot mode (never returns).
+ *   - If not: write the token, wait 500ms, then clear it and boot normally.
+ */
+static const uint32_t magic_token[] = {
+	0xf01681de,
+	0xbd729b29,
+	0xd359be7a,
+};
+
+/* Non-static so the variant's _on_1200_bps() can arm the same magic. */
+uint32_t magic_location[3] __attribute__((section(".noinit.double_tap")));
+
+#define NANO_RP2040_LED_PIN 6
+
+int double_tap_check(void) {
+	if (magic_location[0] == magic_token[0] && magic_location[1] == magic_token[1] &&
+		magic_location[2] == magic_token[2]) {
+		magic_location[0] = 0;
+		reset_usb_boot(1 << NANO_RP2040_LED_PIN, 0);
+		/* never returns */
+	}
+
+	for (int i = 0; i < 3; i++) {
+		magic_location[i] = magic_token[i];
+	}
+
+	k_busy_wait(500000);
+
+	magic_location[0] = 0;
+	return 0;
+}
+
+SYS_INIT(double_tap_check, POST_KERNEL, 0);
+#endif
+
 #if defined(CONFIG_INPUT)
 #include <zephyr/kernel.h>
 #include <zephyr/device.h>

loader/llext_exports.c

@@ -378,6 +378,17 @@ EXPORT_AEABI_SYM(__aeabi_idivmod);
 EXPORT_AEABI_SYM(__aeabi_uidivmod);
 EXPORT_AEABI_SYM(__aeabi_ldivmod);
 EXPORT_AEABI_SYM(__aeabi_uldivmod);
+
+#if defined(__ARM_ARCH_6M__) || (defined(__ARM_ARCH) && __ARM_ARCH < 7)
+/*
+ * Thumb1 switch-dispatch helpers.
+ */
+EXPORT_AEABI_SYM(__gnu_thumb1_case_uqi);
+EXPORT_AEABI_SYM(__gnu_thumb1_case_sqi);
+EXPORT_AEABI_SYM(__gnu_thumb1_case_uhi);
+EXPORT_AEABI_SYM(__gnu_thumb1_case_shi);
+EXPORT_AEABI_SYM(__gnu_thumb1_case_si);
+#endif
 #endif
 
 #if defined(CONFIG_CPP)
@@ -443,7 +454,7 @@ EXPORT_SYMBOL(arm_irq_is_enabled);
 EXPORT_SYMBOL(arm_irq_priority_set);
 #endif
 
-#if defined(__arm__)
+#if defined(__arm__) && !defined(CONFIG_SOC_FAMILY_RPI_PICO)
 EXPORT_SYMBOL(SystemCoreClock);
 #endif
 
@@ -455,3 +466,8 @@ STRUCT_SECTION_END_EXTERN(device);
 EXPORT_SYMBOL(TYPE_SECTION_START(device));
 EXPORT_SYMBOL(TYPE_SECTION_END(device));
 #endif
+
+#if defined(CONFIG_BOARD_ARDUINO_NANO_CONNECT)
+extern uint32_t magic_location[3];
+EXPORT_SYMBOL(magic_location);
+#endif

platform.txt

@@ -251,7 +251,15 @@ tools.picotool.path={runtime.tools.rp2040tools.path}
 tools.picotool.cmd=rp2040load
 tools.picotool.upload.params.verbose=-v
 tools.picotool.upload.params.quiet=
-tools.picotool.upload.pattern="{path}/{cmd}" {upload.verbose} -D "{build.path}/{build.project_name}.elf"
+tools.picotool.upload.pattern="{path}/{cmd}" {upload.verbose} -D "{build.path}/{build.project_name}"
+
+tools.picotool.erase.params.verbose=
+tools.picotool.erase.params.quiet=
+tools.picotool.erase.pattern=
+
+tools.picotool.bootloader.params.verbose=-v
+tools.picotool.bootloader.params.quiet=
+tools.picotool.bootloader.pattern="{path}/{cmd}" {upload.verbose} -D "{runtime.platform.path}/firmwares/{bootloader.file}"
 
 #
 # IMGTOOL

variants/arduino_nano_connect_rp2040/arduino_nano_connect_rp2040.conf

@@ -0,0 +1,25 @@
+# Copyright (c) Arduino s.r.l. and/or its affiliated companies
+# SPDX-License-Identifier: Apache-2.0
+
+CONFIG_USB_DEVICE_STACK=y
+CONFIG_USB_DEVICE_PRODUCT="Arduino Nano RP2040 Connect"
+CONFIG_USB_DEVICE_MANUFACTURER="Arduino"
+CONFIG_USB_DEVICE_VID=0x2341
+CONFIG_USB_DEVICE_PID=0x005E
+
+CONFIG_USB_CDC_ACM=y
+CONFIG_USB_CDC_ACM_RINGBUF_SIZE=1024
+CONFIG_UART_LINE_CTRL=y
+CONFIG_CDC_ACM_DTE_RATE_CALLBACK_SUPPORT=y
+
+CONFIG_HEAP_MEM_POOL_SIZE=16384
+CONFIG_MAIN_STACK_SIZE=32768
+CONFIG_LLEXT_HEAP_SIZE=64
+
+CONFIG_LLEXT_STORAGE_WRITABLE=n
+CONFIG_USB_DEVICE_INITIALIZE_AT_BOOT=n
+
+CONFIG_ADC=y
+CONFIG_DAC=n
+CONFIG_PWM=y
+