ports/rp2: Configure Waveshare RP2350-USB-A for PIO USB host.

Reconfigure for dual-mode USB: native USB controller in device mode
(USB-C, REPL) on rhport 0, PIO USB in host mode (USB-A receptacle,
GPIO12/13) on rhport 1.

Set system clock to 120MHz (multiple of 12MHz required by PIO USB).
RP2350 default 150MHz doesn't divide evenly.

The original board config assumed native dual-controller host mode
which doesn't work as the RP2350 has only one USB controller. PIO USB
provides the second port via PIO state machines.

Tested on Waveshare RP2350-USB-A with ESP32-S3 native USB CDC device
connected to the USB-A receptacle. Host enumeration, CDC read/write
all verified.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

Author: pi-anl

ports/rp2/boards/WAVESHARE_RP2350_USB_A/mpconfigboard.cmake

@@ -6,5 +6,15 @@ set(MICROPY_PY_BTREE 1)
 # Set the board variant for the Pico SDK
 set(PICO_BOARD "waveshare_rp2350_one")
 
-# Enable USB Host support
-set(MICROPY_HW_USB_HOST 1)
+# Enable USB Host support via PIO USB
+set(MICROPY_HW_USB_HOST 1)
+
+# PIO USB requires sys clock to be a multiple of 12MHz.
+# RP2350 default is 150MHz which doesn't divide evenly.
+# 120MHz = 1440MHz VCO / (6 * 2)
+add_compile_definitions(
+    SYS_CLK_KHZ=120000
+    PLL_SYS_VCO_FREQ_HZ=1440000000
+    PLL_SYS_POSTDIV1=6
+    PLL_SYS_POSTDIV2=2
+)

ports/rp2/boards/WAVESHARE_RP2350_USB_A/mpconfigboard.h

@@ -4,9 +4,30 @@
 #define MICROPY_HW_BOARD_NAME          "Waveshare RP2350-USB-A"
 #define MICROPY_HW_FLASH_STORAGE_BYTES (PICO_FLASH_SIZE_BYTES - 1024 * 1024)
 
-// Enable USB Host functionality
+// USB Host via PIO USB on USB-A connector (GPIO12=D+, GPIO13=D-)
+// Native USB controller remains in device mode for CDC REPL on USB-C
 #define MICROPY_HW_USB_HOST            (1)
 
+// PIO USB D+ pin (D- is implicitly D+ + 1 = GPIO13)
+#define MICROPY_HW_USB_HOST_DP_PIN     (12)
+
+// Dual-mode USB: native device on rhport 0, PIO USB host on rhport 1
+#define BOARD_TUD_RHPORT               0
+#define BOARD_TUH_RHPORT               1
+#define CFG_TUH_RPI_PIO_USB            1
+
+// Tell TinyUSB which rhport is device vs host mode.
+// Using raw values (0x0001=DEVICE, 0x0002=HOST, 0x0200=FULL_SPEED) because
+// OPT_MODE_* may not be defined when mpconfigboard.h is included outside
+// TinyUSB context. tusb_option.h checks these before selecting HCD/DCD.
+#define CFG_TUSB_RHPORT0_MODE          (0x0201)  // OPT_MODE_DEVICE | OPT_MODE_FULL_SPEED
+#define CFG_TUSB_RHPORT1_MODE          (0x0202)  // OPT_MODE_HOST | OPT_MODE_FULL_SPEED
+
+// PIO USB requires sys clock to be a multiple of 12MHz.
+// RP2350 default is 150MHz which doesn't divide evenly.
+// SYS_CLK_KHZ=120000 is set in mpconfigboard.cmake so pico-sdk
+// sees it early enough during clock init.
+
 // UART config
 #define MICROPY_HW_UART0_TX            (0)
 #define MICROPY_HW_UART0_RX            (1)
@@ -32,6 +53,8 @@
 
 #define MICROPY_HW_SPI1_SCK            (10)
 #define MICROPY_HW_SPI1_MOSI           (11)
+// Note: GPIO12 is shared with PIO USB host D+ pin. Do not use SPI1 MISO
+// when USB host is active.
 #define MICROPY_HW_SPI1_MISO           (12)
 
 // LEDs

ports/rp2/boards/WAVESHARE_RP2350_USB_A/tusb_config.h

@@ -25,19 +25,18 @@
 #ifndef MICROPY_INCLUDED_RP2_TUSB_CONFIG_H
 #define MICROPY_INCLUDED_RP2_TUSB_CONFIG_H
 
-#include "py/mpconfig.h"
-#include "mpconfigport.h"
-
-// Use the default TinyUSB config
-#include "../../tusb_config.h"
-
-// Use native USB controllers for both host and device mode on RP2350
-#if CFG_TUH_ENABLED
-#define CFG_TUH_RPI_PIO_USB   0  // Disable PIO USB, use native controllers
-#define BOARD_TUH_RHPORT      1  // Use USB1 for host mode
-
-// Use native USB for device mode
-#define BOARD_TUD_RHPORT      0  // Use USB0 for device mode
+// Dual-mode USB: native device (USB-C) + PIO USB host (USB-A)
+// These are defined in mpconfigboard.h for early visibility but
+// repeated here with guards for TinyUSB source files that include
+// tusb_config.h without going through mpconfigboard.h first.
+#ifndef BOARD_TUD_RHPORT
+#define BOARD_TUD_RHPORT     0
+#endif
+#ifndef BOARD_TUH_RHPORT
+#define BOARD_TUH_RHPORT     1
+#endif
+#ifndef CFG_TUH_RPI_PIO_USB
+#define CFG_TUH_RPI_PIO_USB  1
 #endif
 
 #endif // MICROPY_INCLUDED_RP2_TUSB_CONFIG_H