replace printer_to_hid example with printer_to_cdc example

fix printer GET_DEVICE_ID request weird wIndex (interface high, alt low)

6 files changed, 517 insertions, 0 deletions

diff --git a/examples/device/printer_to_cdc/CMakeLists.txt b/examples/device/printer_to_cdc/CMakeLists.txt
new file mode 100644
index 000000000..3c8ab3653
--- /dev/null
+++ b/examples/device/printer_to_cdc/CMakeLists.txt
@@ -0,0 +1,29 @@
+cmake_minimum_required(VERSION 3.20)
+
+include(${CMAKE_CURRENT_SOURCE_DIR}/../../../hw/bsp/family_support.cmake)
+
+project(printer_to_cdc C CXX ASM)
+
+# Checks this example is valid for the family and initializes the project
+family_initialize_project(${PROJECT_NAME} ${CMAKE_CURRENT_LIST_DIR})
+# Espressif has its own cmake build system
+if(FAMILY STREQUAL "espressif")
+  return()
+endif()
+
+add_executable(${PROJECT_NAME})
+
+# Example source
+target_sources(${PROJECT_NAME} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/main.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/usb_descriptors.c
+        )
+
+# Example include
+target_include_directories(${PROJECT_NAME} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src
+        )
+
+# Configure compilation flags and libraries for the example without RTOS.
+# See the corresponding function in hw/bsp/FAMILY/family.cmake for details.
+family_configure_device_example(${PROJECT_NAME} noos)
diff --git a/examples/device/printer_to_cdc/Makefile b/examples/device/printer_to_cdc/Makefile
new file mode 100644
index 000000000..1a4b428dc
--- /dev/null
+++ b/examples/device/printer_to_cdc/Makefile
@@ -0,0 +1,11 @@
+include ../../../hw/bsp/family_support.mk
+
+INC += \
+	src \
+
+
+# Example source
+EXAMPLE_SOURCE += $(wildcard src/*.c)
+SRC_C += $(addprefix $(EXAMPLE_PATH)/, $(EXAMPLE_SOURCE))
+
+include ../../../hw/bsp/family_rules.mk
diff --git a/examples/device/printer_to_cdc/src/main.c b/examples/device/printer_to_cdc/src/main.c
new file mode 100644
index 000000000..aba79025c
--- /dev/null
+++ b/examples/device/printer_to_cdc/src/main.c
@@ -0,0 +1,115 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2026 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+/* This example demonstrates a USB Printer + CDC composite device.
+ * Data received on the Printer interface is forwarded to the CDC serial port,
+ * and data received on the CDC serial port is forwarded back to the Printer interface.
+ *
+ * To test:
+ *   1. Flash the device
+ *   2. Open a serial terminal on the CDC port (e.g. /dev/ttyACM0)
+ *   3. Send data to the printer: echo "hello" > /dev/usb/lp0
+ *   4. The data appears on the CDC serial terminal
+ *   5. Type in the serial terminal to send data back through the printer TX
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "bsp/board_api.h"
+#include "tusb.h"
+
+#include "usb_descriptors.h"
+
+// -------------------------------------------------------------------+
+// Tasks
+// -------------------------------------------------------------------+
+
+// Forward data from Printer RX to CDC TX
+static void printer_to_cdc_task(void) {
+  if (tud_printer_read_available() == 0 || !tud_cdc_write_available()) {
+    return;
+  }
+
+  uint8_t buf[64];
+  uint32_t count = tud_printer_read(buf, sizeof(buf));
+  if (count > 0) {
+    tud_cdc_write(buf, count);
+    tud_cdc_write_flush();
+  }
+}
+
+// Forward data from CDC RX to Printer TX
+static void cdc_to_printer_task(void) {
+  if (tud_cdc_available() == 0 || !tud_printer_write_available()) {
+    return;
+  }
+
+  uint8_t buf[64];
+  uint32_t count = tud_cdc_read(buf, sizeof(buf));
+  if (count > 0) {
+    tud_printer_write(buf, count);
+    tud_printer_write_flush();
+  }
+}
+
+int main(void) {
+  board_init();
+  // init device stack on configured roothub port
+  tusb_rhport_init_t dev_init = {.role = TUSB_ROLE_DEVICE, .speed = TUSB_SPEED_AUTO};
+  tusb_init(BOARD_TUD_RHPORT, &dev_init);
+  board_init_after_tusb();
+
+  while (1) {
+    tud_task();             // tinyusb device task
+    printer_to_cdc_task();  // forward printer data to CDC
+    cdc_to_printer_task();  // forward CDC data to printer
+  }
+}
+
+//--------------------------------------------------------------------+
+// Printer callbacks
+//--------------------------------------------------------------------+
+
+void tud_printer_rx_cb(uint8_t itf) {
+  (void)itf;
+}
+
+// IEEE 1284 Device ID: first 2 bytes are big-endian total length (including the 2 length bytes).
+// The rest is the Device ID string using standard abbreviated keys.
+static const char printer_device_id[] =
+  "\x00\x34" // total length = 52 = 0x0034 (big-endian)
+  "MFG:TinyUSB;"
+  "MDL:Printer to CDC;"
+  "CMD:PS;"
+  "CLS:PRINTER;";
+
+TU_VERIFY_STATIC(sizeof(printer_device_id) - 1 == 52, "device ID length mismatch");
+
+uint8_t const *tud_printer_get_device_id_cb(uint8_t itf) {
+  (void)itf;
+  return (uint8_t const *)printer_device_id;
+}
diff --git a/examples/device/printer_to_cdc/src/tusb_config.h b/examples/device/printer_to_cdc/src/tusb_config.h
new file mode 100644
index 000000000..50ef41762
--- /dev/null
+++ b/examples/device/printer_to_cdc/src/tusb_config.h
@@ -0,0 +1,117 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2026 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#ifndef _TUSB_CONFIG_H_
+#define _TUSB_CONFIG_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//--------------------------------------------------------------------+
+// Board Specific Configuration
+//--------------------------------------------------------------------+
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_TUD_RHPORT
+  #define BOARD_TUD_RHPORT 0
+#endif
+
+// RHPort max operational speed can defined by board.mk
+#ifndef BOARD_TUD_MAX_SPEED
+  #define BOARD_TUD_MAX_SPEED OPT_MODE_DEFAULT_SPEED
+#endif
+
+//--------------------------------------------------------------------
+// COMMON CONFIGURATION
+//--------------------------------------------------------------------
+
+// defined by compiler flags for flexibility
+#ifndef CFG_TUSB_MCU
+  #error CFG_TUSB_MCU must be defined
+#endif
+
+#ifndef CFG_TUSB_OS
+  #define CFG_TUSB_OS OPT_OS_NONE
+#endif
+
+#ifndef CFG_TUSB_DEBUG
+  #define CFG_TUSB_DEBUG 0
+#endif
+
+// Enable Device stack
+#define CFG_TUD_ENABLED 1
+
+// Default is max speed that hardware controller could support with on-chip PHY
+#define CFG_TUD_MAX_SPEED BOARD_TUD_MAX_SPEED
+
+/* USB DMA on some MCUs can only access a specific SRAM region with restriction on alignment.
+ * Tinyusb use follows macros to declare transferring memory so that they can be put
+ * into those specific section.
+ * e.g
+ * - CFG_TUSB_MEM SECTION : __attribute__ (( section(".usb_ram") ))
+ * - CFG_TUSB_MEM_ALIGN   : __attribute__ ((aligned(4)))
+ */
+#ifndef CFG_TUSB_MEM_SECTION
+  #define CFG_TUSB_MEM_SECTION
+#endif
+
+#ifndef CFG_TUSB_MEM_ALIGN
+  #define CFG_TUSB_MEM_ALIGN __attribute__((aligned(4)))
+#endif
+
+//--------------------------------------------------------------------
+// DEVICE CONFIGURATION
+//--------------------------------------------------------------------
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+  #define CFG_TUD_ENDPOINT0_SIZE 64
+#endif
+
+//------------- CLASS -------------//
+#define CFG_TUD_HID     0
+#define CFG_TUD_CDC     1
+#define CFG_TUD_MSC     0
+#define CFG_TUD_MIDI    0
+#define CFG_TUD_VENDOR  0
+#define CFG_TUD_PRINTER 1
+
+// CDC FIFO size of TX and RX
+#define CFG_TUD_CDC_RX_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+#define CFG_TUD_CDC_TX_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+
+// CDC Endpoint transfer buffer size
+#define CFG_TUD_CDC_EP_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+
+// Printer buffer sizes
+#define CFG_TUD_PRINTER_RX_BUFSIZE 512
+#define CFG_TUD_PRINTER_TX_BUFSIZE 512
+#define CFG_TUD_PRINTER_EP_BUFSIZE 512
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/examples/device/printer_to_cdc/src/usb_descriptors.c b/examples/device/printer_to_cdc/src/usb_descriptors.c
new file mode 100644
index 000000000..30d309ed4
--- /dev/null
+++ b/examples/device/printer_to_cdc/src/usb_descriptors.c
@@ -0,0 +1,208 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2026 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include "bsp/board_api.h"
+#include "tusb.h"
+
+#include "usb_descriptors.h"
+
+#define USB_VID   0xCafe
+#define USB_PID   0x4005
+#define USB_BCD   0x0200
+
+//--------------------------------------------------------------------+
+// Device Descriptors
+//--------------------------------------------------------------------+
+static tusb_desc_device_t const desc_device = {
+  .bLength            = sizeof(tusb_desc_device_t),
+  .bDescriptorType    = TUSB_DESC_DEVICE,
+  .bcdUSB             = USB_BCD,
+
+  // Use Interface Association Descriptor (IAD) for CDC
+  // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
+  .bDeviceClass       = TUSB_CLASS_MISC,
+  .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+  .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+  .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+
+  .idVendor           = USB_VID,
+  .idProduct          = USB_PID,
+  .bcdDevice          = 0x0100,
+
+  .iManufacturer      = 0x01,
+  .iProduct           = 0x02,
+  .iSerialNumber      = 0x03,
+
+  .bNumConfigurations = 0x01
+};
+
+uint8_t const *tud_descriptor_device_cb(void) {
+  return (uint8_t const *) &desc_device;
+}
+
+//--------------------------------------------------------------------+
+// Configuration Descriptor
+//--------------------------------------------------------------------+
+
+// Endpoint numbers
+#if defined(TUD_ENDPOINT_ONE_DIRECTION_ONLY)
+  #define EPNUM_CDC_NOTIF   0x81
+  #define EPNUM_CDC_OUT     0x02
+  #define EPNUM_CDC_IN      0x83
+  #define EPNUM_PRINTER_OUT 0x04
+  #define EPNUM_PRINTER_IN  0x85
+#else
+  #define EPNUM_CDC_NOTIF   0x81
+  #define EPNUM_CDC_OUT     0x02
+  #define EPNUM_CDC_IN      0x82
+  #define EPNUM_PRINTER_OUT 0x03
+  #define EPNUM_PRINTER_IN  0x83
+#endif
+
+// full speed configuration
+static uint8_t const desc_fs_configuration[] = {
+  // Config number, interface count, string index, total length, attribute, power in mA
+  TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+  // Interface number, string index, EP notification address and size, EP data address (out, in) and size.
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 16, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),
+
+  // Interface number, string index, EP Bulk Out address, EP Bulk In address, EP size
+  TUD_PRINTER_DESCRIPTOR(ITF_NUM_PRINTER, 5, EPNUM_PRINTER_OUT, EPNUM_PRINTER_IN, 64),
+};
+
+#if TUD_OPT_HIGH_SPEED
+// high speed configuration
+static uint8_t const desc_hs_configuration[] = {
+  TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 16, EPNUM_CDC_OUT, EPNUM_CDC_IN, 512),
+
+  TUD_PRINTER_DESCRIPTOR(ITF_NUM_PRINTER, 5, EPNUM_PRINTER_OUT, EPNUM_PRINTER_IN, 512),
+};
+
+// other speed configuration
+static uint8_t desc_other_speed_config[CONFIG_TOTAL_LEN];
+
+// device qualifier is mostly similar to device descriptor since we don't change configuration based on speed
+static tusb_desc_device_qualifier_t const desc_device_qualifier = {
+  .bLength            = sizeof(tusb_desc_device_qualifier_t),
+  .bDescriptorType    = TUSB_DESC_DEVICE_QUALIFIER,
+  .bcdUSB             = USB_BCD,
+
+  .bDeviceClass       = TUSB_CLASS_MISC,
+  .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+  .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+
+  .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+  .bNumConfigurations = 0x01,
+  .bReserved          = 0x00
+};
+
+uint8_t const *tud_descriptor_device_qualifier_cb(void) {
+  return (uint8_t const *) &desc_device_qualifier;
+}
+
+uint8_t const *tud_descriptor_other_speed_configuration_cb(uint8_t index) {
+  (void) index;
+
+  // if link speed is high return fullspeed config, and vice versa
+  memcpy(desc_other_speed_config,
+         (tud_speed_get() == TUSB_SPEED_HIGH) ? desc_fs_configuration : desc_hs_configuration,
+         CONFIG_TOTAL_LEN);
+
+  desc_other_speed_config[1] = TUSB_DESC_OTHER_SPEED_CONFIG;
+
+  return desc_other_speed_config;
+}
+
+#endif // TUD_OPT_HIGH_SPEED
+
+uint8_t const *tud_descriptor_configuration_cb(uint8_t index) {
+  (void) index;
+
+#if TUD_OPT_HIGH_SPEED
+  return (tud_speed_get() == TUSB_SPEED_HIGH) ? desc_hs_configuration : desc_fs_configuration;
+#else
+  return desc_fs_configuration;
+#endif
+}
+
+//--------------------------------------------------------------------+
+// String Descriptors
+//--------------------------------------------------------------------+
+
+enum {
+  STRID_LANGID = 0,
+  STRID_MANUFACTURER,
+  STRID_PRODUCT,
+  STRID_SERIAL,
+  STRID_CDC,
+  STRID_PRINTER,
+};
+
+static char const *string_desc_arr[] = {
+  (const char[]) { 0x09, 0x04 }, // 0: supported language is English (0x0409)
+  "TinyUSB",                     // 1: Manufacturer
+  "TinyUSB Device",              // 2: Product
+  NULL,                          // 3: Serial, use unique ID if possible
+  "TinyUSB CDC",                 // 4: CDC Interface
+  "TinyUSB Printer",             // 5: Printer Interface
+};
+
+static uint16_t _desc_str[32 + 1];
+
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
+  (void) langid;
+  size_t chr_count;
+
+  switch (index) {
+    case STRID_LANGID:
+      memcpy(&_desc_str[1], string_desc_arr[0], 2);
+      chr_count = 1;
+      break;
+
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
+
+    default:
+      if (!(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0]))) { return NULL; }
+
+      const char *str = string_desc_arr[index];
+
+      chr_count = strlen(str);
+      size_t const max_count = sizeof(_desc_str) / sizeof(_desc_str[0]) - 1;
+      if (chr_count > max_count) { chr_count = max_count; }
+
+      for (size_t i = 0; i < chr_count; i++) {
+        _desc_str[1 + i] = str[i];
+      }
+      break;
+  }
+
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
+  return _desc_str;
+}
diff --git a/examples/device/printer_to_cdc/src/usb_descriptors.h b/examples/device/printer_to_cdc/src/usb_descriptors.h
new file mode 100644
index 000000000..830593b4d
--- /dev/null
+++ b/examples/device/printer_to_cdc/src/usb_descriptors.h
@@ -0,0 +1,37 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2026 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef USB_DESCRIPTORS_H_
+#define USB_DESCRIPTORS_H_
+
+enum {
+  ITF_NUM_CDC,
+  ITF_NUM_CDC_DATA,
+  ITF_NUM_PRINTER,
+  ITF_NUM_TOTAL,
+};
+
+#define CONFIG_TOTAL_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN + TUD_PRINTER_DESC_LEN)
+
+#endif /* USB_DESCRIPTORS_H_ */