diff --git a/src/class/usbtmc/usbtmc.h b/src/class/usbtmc/usbtmc.h
new file mode 100644
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--- /dev/null
+++ b/src/class/usbtmc/usbtmc.h
@@ -0,0 +1,316 @@
+
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 N Conrad
+ *
+ * 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 file is part of the TinyUSB stack.
+ */
+
+#ifndef _TUSB_USBTMC_H__
+#define _TUSB_USBTMC_H__
+
+#include "common/tusb_common.h"
+
+
+/* Implements USBTMC Revision 1.0, April 14, 2003
+
+ String descriptors must have a "LANGID=0x409"/US English string.
+ Characters must be 0x20 (' ') to 0x7E ('~') ASCII,
+   But MUST not contain: "/:?\*
+   Also must not have leading or trailing space (' ')
+ Device descriptor must state USB version 0x0200 or greater
+
+ If USB488DeviceCapabilites.D2 = 1 (SR1), then there must be a INT endpoint.
+*/
+
+#define USBTMC_VERSION 0x0100
+#define USBTMC_488_VERSION 0x0100
+
+typedef enum {
+  USBTMC_MSGID_DEV_DEP_MSG_OUT = 1u,
+  USBTMC_MSGID_DEV_DEP_MSG_IN = 2u,
+  USBTMC_MSGID_VENDOR_SPECIFIC_MSG_OUT = 126u,
+  USBTMC_MSGID_VENDOR_SPECIFIC_IN = 127u,
+  USBTMC_MSGID_USB488_TRIGGER = 128u,
+} usbtmc_msgid_enum;
+
+/// \brief Message header (For BULK OUT and BULK IN); 4 bytes
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t MsgID              ; ///< Message type ID (usbtmc_msgid_enum)
+  uint8_t bTag    		       ; ///< Transfer ID 1<=bTag<=255
+  uint8_t bTagInverse        ; ///< Complement of the tag
+  uint8_t _reserved           ; ///< Must be 0x00
+} usbtmc_msg_header_t;
+
+typedef struct TU_ATTR_PACKED
+{
+  usbtmc_msg_header_t header;
+  uint8_t data[8];
+} usbtmc_msg_generic_t;
+
+/* Uses on the bulk-out endpoint: */
+// Next 8 bytes are message-specific
+typedef struct TU_ATTR_PACKED {
+	usbtmc_msg_header_t header ; ///< Header
+	uint32_t TransferSize      ; ///< Transfer size; LSB first
+	struct TU_ATTR_PACKED
+	{
+	  unsigned int EOM  : 1         ; ///< EOM set on last byte
+  } bmTransferAttributes;
+  uint8_t _reserved[3];
+} usbtmc_msg_request_dev_dep_out;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_msg_request_dev_dep_out) == 12u, "struct wrong length");
+
+// Next 8 bytes are message-specific
+typedef struct TU_ATTR_PACKED
+{
+  usbtmc_msg_header_t header ; ///< Header
+  uint32_t TransferSize      ; ///< Transfer size; LSB first
+  struct TU_ATTR_PACKED
+  {
+    unsigned int TermCharEnabled  : 1 ; ///< "The Bulk-IN transfer must terminate on the specified TermChar."; CAPABILITIES must list TermChar
+  } bmTransferAttributes;
+  uint8_t TermChar;
+  uint8_t _reserved[2];
+} usbtmc_msg_request_dev_dep_in;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_msg_request_dev_dep_in) == 12u, "struct wrong length");
+
+/* Bulk-in headers */
+
+typedef struct TU_ATTR_PACKED
+{
+  usbtmc_msg_header_t header;
+  uint32_t TransferSize;
+  struct TU_ATTR_PACKED
+  {
+    uint8_t EOM: 1;           ///< Last byte of transfer is the end of the message
+    uint8_t UsingTermChar: 1; ///< Support TermChar && Request.TermCharEnabled && last char in transfer is TermChar
+  } bmTransferAttributes;
+  uint8_t _reserved[3];
+} usbtmc_msg_dev_dep_msg_in_header_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_msg_dev_dep_msg_in_header_t) == 12u, "struct wrong length");
+
+/* Unsupported vendor things.... Are these ever used?*/
+
+typedef struct TU_ATTR_PACKED
+{
+  usbtmc_msg_header_t header ; ///< Header
+  uint32_t TransferSize      ; ///< Transfer size; LSB first
+  uint8_t _reserved[4];
+} usbtmc_msg_request_vendor_specific_out;
+
+
+TU_VERIFY_STATIC(sizeof(usbtmc_msg_request_vendor_specific_out) == 12u, "struct wrong length");
+
+typedef struct TU_ATTR_PACKED
+{
+  usbtmc_msg_header_t header ; ///< Header
+  uint32_t TransferSize      ; ///< Transfer size; LSB first
+  uint8_t _reserved[4];
+} usbtmc_msg_request_vendor_specific_in;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_msg_request_vendor_specific_in) == 12u, "struct wrong length");
+
+// Control request type should use tusb_control_request_t
+
+/*
+typedef struct TU_ATTR_PACKED {
+  struct {
+    unsigned int Recipient  : 5         ; ///< EOM set on last byte
+    unsigned int Type       : 2         ; ///< EOM set on last byte
+    unsigned int DirectionToHost  : 1   ; ///< 0 is OUT, 1 is IN
+  } bmRequestType;
+  uint8_t bRequest                 ; ///< If bmRequestType.Type = Class, see usmtmc_request_type_enum
+  uint16_t wValue                  ;
+  uint16_t wIndex                  ;
+  uint16_t wLength                 ; // Number of bytes in data stage
+} usbtmc_class_specific_control_req;
+
+*/
+// bulk-in protocol errors
+enum {
+  USBTMC_BULK_IN_ERR_INCOMPLETE_HEADER = 1u,
+  USBTMC_BULK_IN_ERR_UNSUPPORTED = 2u,
+  USBTMC_BULK_IN_ERR_BAD_PARAMETER = 3u,
+  USBTMC_BULK_IN_ERR_DATA_TOO_SHORT = 4u,
+  USBTMC_BULK_IN_ERR_DATA_TOO_LONG = 5u,
+};
+// bult-in halt errors
+enum {
+  USBTMC_BULK_IN_ERR = 1u, ///< receives a USBTMC command message that expects a response while a
+                           /// Bulk-IN transfer is in progress
+};
+
+typedef enum {
+  USBTMC_bREQUEST_INITIATE_ABORT_BULK_OUT      = 1u,
+  USBTMC_bREQUEST_CHECK_ABORT_BULK_OUT_STATUS  = 2u,
+  USBTMC_bREQUEST_INITIATE_ABORT_BULK_IN       = 3u,
+  USBTMC_bREQUEST_CHECK_ABORT_BULK_IN_STATUS   = 4u,
+  USBTMC_bREQUEST_INITIATE_CLEAR               = 5u,
+  USBTMC_bREQUEST_CHECK_CLEAR_STATUS           = 6u,
+  USBTMC_bREQUEST_GET_CAPABILITIES             = 7u,
+
+  USBTMC_bREQUEST_INDICATOR_PULSE               = 64u, // Optional
+
+  /****** USBTMC 488 *************/
+  USB488_bREQUEST_READ_STATUS_BYTE  = 128u,
+  USB488_bREQUEST_REN_CONTROL       = 160u,
+  USB488_bREQUEST_GO_TO_LOCAL       = 161u,
+  USB488_bREQUEST_LOCAL_LOCKOUT     = 162u,
+
+} usmtmc_request_type_enum;
+
+typedef enum {
+  USBTMC_STATUS_SUCCESS = 0x01,
+  USBTMC_STATUS_PENDING = 0x02,
+  USBTMC_STATUS_FAILED = 0x80,
+  USBTMC_STATUS_TRANSFER_NOT_IN_PROGRESS = 0x81,
+  USBTMC_STATUS_SPLIT_NOT_IN_PROGRESS = 0x82,
+  USBTMC_STATUS_SPLIT_IN_PROGRESS  = 0x83
+} usbtmc_status_enum;
+
+/************************************************************
+ * Control Responses
+ */
+
+typedef struct TU_ATTR_PACKED {
+  uint8_t USBTMC_status;                 ///< usbtmc_status_enum
+  uint8_t _reserved;
+  uint16_t bcdUSBTMC;                    ///< USBTMC_VERSION
+
+  struct TU_ATTR_PACKED
+  {
+    unsigned int listenOnly :1;
+    unsigned int talkOnly :1;
+    unsigned int supportsIndicatorPulse :1;
+  } bmIntfcCapabilities;
+  struct TU_ATTR_PACKED
+  {
+    unsigned int canEndBulkInOnTermChar :1;
+  } bmDevCapabilities;
+  uint8_t _reserved2[6];
+  uint8_t _reserved3[12];
+} usbtmc_response_capabilities_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_response_capabilities_t) == 0x18, "struct wrong length");
+
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t USBTMC_status;
+  struct TU_ATTR_PACKED
+  {
+    unsigned int BulkInFifoBytes :1;
+  } bmClear;
+} usbtmc_get_clear_status_rsp_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_get_clear_status_rsp_t) == 2u, "struct wrong length");
+
+// Used for both abort bulk IN and bulk OUT
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t USBTMC_status;
+  uint8_t bTag;
+} usbtmc_initiate_abort_rsp_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_get_clear_status_rsp_t) == 2u, "struct wrong length");
+
+// Used for both check_abort_bulk_in_status and check_abort_bulk_out_status
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t USBTMC_status;
+  struct TU_ATTR_PACKED
+  {
+    unsigned int BulkInFifoBytes : 1; ///< Has queued data or a short packet that is queued
+  } bmAbortBulkIn;
+  uint8_t _reserved[2];               ///< Must be zero
+  uint32_t NBYTES_RXD_TXD;
+} usbtmc_check_abort_bulk_rsp_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_check_abort_bulk_rsp_t) == 8u, "struct wrong length");
+
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t USBTMC_status;                 ///< usbtmc_status_enum
+  uint8_t _reserved;
+  uint16_t bcdUSBTMC;                    ///< USBTMC_VERSION
+
+  struct TU_ATTR_PACKED
+  {
+    unsigned int listenOnly :1;
+    unsigned int talkOnly :1;
+    unsigned int supportsIndicatorPulse :1;
+  } bmIntfcCapabilities;
+
+  struct TU_ATTR_PACKED
+  {
+    unsigned int canEndBulkInOnTermChar :1;
+  } bmDevCapabilities;
+
+  uint8_t _reserved2[6];
+  uint16_t bcdUSB488;
+
+  struct TU_ATTR_PACKED
+  {
+    unsigned int is488_2 :1;
+    unsigned int supportsREN_GTL_LLO :1;
+    unsigned int supportsTrigger :1;
+  } bmIntfcCapabilities488;
+
+  struct TU_ATTR_PACKED
+  {
+    unsigned int SCPI :1;
+    unsigned int SR1 :1;
+    unsigned int RL1 :1;
+    unsigned int DT1 :1;
+  } bmDevCapabilities488;
+  uint8_t _reserved3[8];
+} usbtmc_response_capabilities_488_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_response_capabilities_488_t) == 0x18, "struct wrong length");
+
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t USBTMC_status;
+  uint8_t bTag;
+  uint8_t statusByte;
+} usbtmc_read_stb_rsp_488_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_read_stb_rsp_488_t) == 3u, "struct wrong length");
+
+typedef struct TU_ATTR_PACKED
+{
+  struct TU_ATTR_PACKED
+  {
+      unsigned int bTag : 7;
+      unsigned int one  : 1;
+  } bNotify1;
+  uint8_t StatusByte;
+} usbtmc_read_stb_interrupt_488_t;
+
+TU_VERIFY_STATIC(sizeof(usbtmc_read_stb_interrupt_488_t) == 2u, "struct wrong length");
+
+#endif
+