LUFA/Drivers/USB/LowLevel/OTG.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *  \brief USB OTG mode definitions.
  33  *
  34  *  This file contains structures, function prototypes and macros related to USB OTG mode, where two USB devices
  35  *  may be linked directly together and exchange host/device roles as needed.
  36  *
  37  *  \note This file should not be included directly. It is automatically included as needed by the USB driver
  38  *        dispatch header located in LUFA/Drivers/USB/USB.h.
  39  */
  40
  41 /** \ingroup Group_USB
  42  *  @defgroup Group_OTG USB On The Go (OTG) Management
  43  *
  44  *  This module contains macros for embedded USB hosts with dual role On The Go capabilities, for managing role
  45  *  exchange. OTG is a way for two USB dual role devices to talk to one another directly without fixed device/host
  46  *  roles.
  47  *
  48  *  @{
  49  */
  50
  51 #ifndef __USBOTG_H__
  52 #define __USBOTG_H__
  53
  54         /* Includes: */
  55                 #include <avr/io.h>
  56                 #include <stdbool.h>
  57
  58                 #include "../../../Common/Common.h"
  59
  60         /* Preprocessor Checks: */
  61                 #if !defined(__INCLUDE_FROM_USB_DRIVER)
  62                         #error Do not include this file directly. Include LUFA/Drivers/USB/USB.h instead.
  63                 #endif
  64
  65         /* Public Interface - May be used in end-application: */
  66                 /* Macros: */
  67                         /** Mask for the VBUS pulsing method of SRP, supported by some OTG devices.
  68                          *
  69                          *  \see \ref USB_OTG_Device_InitiateSRP().
  70                          */
  71                         #define USB_OTG_SRP_VBUS                   (1 << SRPSEL)
  72
  73                         /** Mask for the Data + pulsing method of SRP, supported by some OTG devices.
  74                          *
  75                          *  \see \ref USB_OTG_Device_InitiateSRP().
  76                          */
  77                         #define USB_OTG_STP_DATA                   0
  78
  79                 /* Inline Functions: */
  80                         /** Initiate a Host Negotiation Protocol request. This indicates to the other connected device
  81                          *  that the device wishes to change device/host roles.
  82                          */
  83                         static inline void USB_OTG_Device_RequestHNP(void) ATTR_ALWAYS_INLINE;
  84                         static inline void USB_OTG_Device_RequestHNP(void)
  85                         {
  86                                 OTGCON |=  (1 << HNPREQ);
  87                         }
  88
  89                         /** Cancel a Host Negotiation Protocol request. This stops a pending HNP request to the other
  90                          *  connected device.
  91                          */
  92                         static inline void USB_OTG_Device_CancelHNPRequest(void) ATTR_ALWAYS_INLINE;
  93                         static inline void USB_OTG_Device_CancelHNPRequest(void)
  94                         {
  95                                 OTGCON &= ~(1 << HNPREQ);
  96                         }
  97
  98                         /** Determines if the device is currently sending a HNP to an attached host.
  99                          *
 100                          *  \return Boolean \c true if currently sending a HNP to the other connected device, \c false otherwise
 101                          */
 102                         static inline bool USB_OTG_Device_IsSendingHNP(void) ATTR_ALWAYS_INLINE;
 103                         static inline bool USB_OTG_Device_IsSendingHNP(void)
 104                         {
 105                                 return ((OTGCON & (1 << HNPREQ)) ? true : false);
 106                         }
 107
 108                         /** Initiates a Session Request Protocol request. Most OTG devices turn off VBUS when the USB
 109                          *  interface is not in use, to conserve power. Sending a SRP to a USB OTG device running in
 110                          *  host mode indicates that VBUS should be applied and a session started.
 111                          *
 112                          *  There are two different methods of sending a SRP - either pulses on the VBUS line, or by
 113                          *  pulsing the Data + line via the internal pull-up resistor.
 114                          *
 115                          *  \param[in] SRPTypeMask  Mask indicating the type of SRP to use, either \ref USB_OTG_SRP_VBUS or
 116                          *                          \ref USB_OTG_STP_DATA.
 117                          */
 118                         static inline void USB_OTG_Device_InitiateSRP(const uint8_t SRPTypeMask) ATTR_ALWAYS_INLINE;
 119                         static inline void USB_OTG_Device_InitiateSRP(const uint8_t SRPTypeMask)
 120                         {
 121                                 OTGCON = ((OTGCON & ~(1 << SRPSEL)) | (SRPTypeMask | (1 << SRPREQ)));
 122                         }
 123
 124                         /** Accepts a HNP from a connected device, indicating that both devices should exchange
 125                          *  device/host roles.
 126                          */
 127                         static inline void USB_OTG_Host_AcceptHNP(void) ATTR_ALWAYS_INLINE;
 128                         static inline void USB_OTG_Host_AcceptHNP(void)
 129                         {
 130                                 OTGCON |=  (1 << HNPREQ);
 131                         }
 132
 133                         /** Rejects a HNP from a connected device, indicating that both devices should remain in their
 134                          *  current device/host roles.
 135                          */
 136                         static inline void USB_OTG_Host_RejectHNP(void) ATTR_ALWAYS_INLINE;
 137                         static inline void USB_OTG_Host_RejectHNP(void)
 138                         {
 139                                 OTGCON &= ~(1 << HNPREQ);
 140                         }
 141
 142                         /** Indicates if the connected device is not currently sending a HNP request.
 143                          *
 144                          *  \return Boolean \c true if a HNP is currently being issued by the connected device, \c false otherwise.
 145                          */
 146                         static inline bool USB_OTG_Host_IsHNPReceived(void) ATTR_WARN_UNUSED_RESULT ATTR_ALWAYS_INLINE;
 147                         static inline bool USB_OTG_Host_IsHNPReceived(void)
 148                         {
 149                                 return ((OTGCON & (1 << HNPREQ)) ? true : false);
 150                         }
 151
 152 #endif
 153
 154 /** @} */
 155