Output/pjrcUSB/arm/usb_serial.c

   1 /* Teensyduino Core Library
   2  * http://www.pjrc.com/teensy/
   3  * Copyright (c) 2013 PJRC.COM, LLC.
   4  * Modified by Jacob Alexander 2013-2015
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining
   7  * a copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sublicense, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * 1. The above copyright notice and this permission notice shall be
  15  * included in all copies or substantial portions of the Software.
  16  *
  17  * 2. If the Software is incorporated into a build system that allows
  18  * selection among a list of target devices, then similar target
  19  * devices manufactured by PJRC.COM must be included in the list of
  20  * target devices and selectable in the same manner.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  26  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  27  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  28  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  29  * SOFTWARE.
  30  */
  31
  32 // ----- Includes -----
  33
  34 // Compiler Includes
  35 #include <string.h> // For memcpy
  36
  37 // Project Includes
  38 #include <Lib/OutputLib.h>
  39
  40 // Local Includes
  41 #include "usb_dev.h"
  42 #include "usb_serial.h"
  43
  44
  45
  46 // ----- Defines -----
  47
  48 #define TRANSMIT_FLUSH_TIMEOUT  5   /* in milliseconds */
  49
  50 // Maximum number of transmit packets to queue so we don't starve other endpoints for memory
  51 #define TX_PACKET_LIMIT 8
  52
  53 // When the PC isn't listening, how long do we wait before discarding data?  If this is
  54 // too short, we risk losing data during the stalls that are common with ordinary desktop
  55 // software.  If it's too long, we stall the user's program when no software is running.
  56 #define TX_TIMEOUT_MSEC 70
  57
  58 #if F_CPU == 96000000
  59         #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 596)
  60 #elif F_CPU == 72000000
  61         #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 512) // XXX Correct?
  62 #elif F_CPU == 48000000
  63         #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 428)
  64 #elif F_CPU == 24000000
  65         #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 262)
  66 #endif
  67
  68
  69
  70 // ----- Variables -----
  71
  72 // serial port settings (baud rate, control signals, etc) set
  73 // by the PC.  These are ignored, but kept in RAM.
  74 volatile uint8_t usb_cdc_line_coding[7] = { 0x00, 0xE1, 0x00, 0x00, 0x00, 0x00, 0x08 };
  75 volatile uint8_t usb_cdc_line_rtsdtr = 0;
  76 volatile uint8_t usb_cdc_transmit_flush_timer = 0;
  77
  78 static usb_packet_t *rx_packet = NULL;
  79 static usb_packet_t *tx_packet = NULL;
  80 static volatile uint8_t tx_noautoflush = 0;
  81
  82 // When we've suffered the transmit timeout, don't wait again until the computer
  83 // begins accepting data.  If no software is running to receive, we'll just discard
  84 // data as rapidly as Serial.print() can generate it, until there's something to
  85 // actually receive it.
  86 static uint8_t transmit_previous_timeout = 0;
  87
  88
  89
  90 // ----- Functions -----
  91
  92 // get the next character, or -1 if nothing received
  93 int usb_serial_getchar()
  94 {
  95         unsigned int i;
  96         int c;
  97
  98         if ( !rx_packet )
  99         {
 100                 if ( !usb_configuration )
 101                         return -1;
 102                 rx_packet = usb_rx( CDC_RX_ENDPOINT );
 103                 if ( !rx_packet )
 104                         return -1;
 105         }
 106         i = rx_packet->index;
 107         c = rx_packet->buf[i++];
 108         if ( i >= rx_packet->len )
 109         {
 110                 usb_free( rx_packet );
 111                 rx_packet = NULL;
 112         }
 113         else
 114         {
 115                 rx_packet->index = i;
 116         }
 117         return c;
 118 }
 119
 120 // peek at the next character, or -1 if nothing received
 121 int usb_serial_peekchar()
 122 {
 123         if ( !rx_packet )
 124         {
 125                 if ( !usb_configuration )
 126                         return -1;
 127                 rx_packet = usb_rx( CDC_RX_ENDPOINT );
 128                 if ( !rx_packet )
 129                         return -1;
 130         }
 131         if ( !rx_packet )
 132                 return -1;
 133         return rx_packet->buf[ rx_packet->index ];
 134 }
 135
 136 // number of bytes available in the receive buffer
 137 int usb_serial_available()
 138 {
 139         int count = usb_rx_byte_count( CDC_RX_ENDPOINT );
 140         if ( rx_packet )
 141                 count += rx_packet->len - rx_packet->index;
 142         return count;
 143 }
 144
 145 // read a block of bytes to a buffer
 146 int usb_serial_read( void *buffer, uint32_t size )
 147 {
 148         uint8_t *p = (uint8_t *)buffer;
 149         uint32_t qty, count=0;
 150
 151         while ( size )
 152         {
 153                 if ( !usb_configuration )
 154                         break;
 155                 if ( !rx_packet )
 156                 {
 157                         rx:
 158                                 rx_packet = usb_rx(CDC_RX_ENDPOINT);
 159                                 if ( !rx_packet )
 160                                         break;
 161                                 if ( rx_packet->len == 0 )
 162                                 {
 163                                         usb_free(rx_packet);
 164                                         goto rx;
 165                                 }
 166                 }
 167                 qty = rx_packet->len - rx_packet->index;
 168                 if ( qty > size )
 169                         qty = size;
 170                 memcpy( p, rx_packet->buf + rx_packet->index, qty );
 171                 p += qty;
 172                 count += qty;
 173                 size -= qty;
 174                 rx_packet->index += qty;
 175                 if ( rx_packet->index >= rx_packet->len )
 176                 {
 177                         usb_free( rx_packet );
 178                         rx_packet = NULL;
 179                 }
 180         }
 181         return count;
 182 }
 183
 184 // discard any buffered input
 185 void usb_serial_flush_input()
 186 {
 187         usb_packet_t *rx;
 188
 189         if ( !usb_configuration )
 190                 return;
 191         if ( rx_packet )
 192         {
 193                 usb_free( rx_packet );
 194                 rx_packet = NULL;
 195         }
 196         while (1)
 197         {
 198                 rx = usb_rx( CDC_RX_ENDPOINT );
 199                 if ( !rx )
 200                         break;
 201                 usb_free( rx );
 202         }
 203 }
 204
 205 // transmit a character.  0 returned on success, -1 on error
 206 int usb_serial_putchar( uint8_t c )
 207 {
 208         return usb_serial_write( &c, 1 );
 209 }
 210
 211 int usb_serial_write( const void *buffer, uint32_t size )
 212 {
 213         uint32_t len;
 214         uint32_t wait_count;
 215         const uint8_t *src = (const uint8_t *)buffer;
 216         uint8_t *dest;
 217
 218         tx_noautoflush = 1;
 219         while ( size > 0 )
 220         {
 221                 if ( !tx_packet )
 222                 {
 223                         wait_count = 0;
 224                         while ( 1 )
 225                         {
 226                                 if ( !usb_configuration )
 227                                 {
 228                                         tx_noautoflush = 0;
 229                                         return -1;
 230                                 }
 231                                 if ( usb_tx_packet_count( CDC_TX_ENDPOINT ) < TX_PACKET_LIMIT )
 232                                 {
 233                                         tx_noautoflush = 1;
 234                                         tx_packet = usb_malloc();
 235                                         if ( tx_packet )
 236                                                 break;
 237                                         tx_noautoflush = 0;
 238                                 }
 239                                 if ( ++wait_count > TX_TIMEOUT || transmit_previous_timeout )
 240                                 {
 241                                         transmit_previous_timeout = 1;
 242                                         return -1;
 243                                 }
 244                                 yield();
 245                         }
 246                 }
 247                 transmit_previous_timeout = 0;
 248                 len = CDC_TX_SIZE - tx_packet->index;
 249                 if ( len > size )
 250                         len = size;
 251                 dest = tx_packet->buf + tx_packet->index;
 252                 tx_packet->index += len;
 253                 size -= len;
 254                 while ( len-- > 0 )
 255                         *dest++ = *src++;
 256                 if ( tx_packet->index >= CDC_TX_SIZE )
 257                 {
 258                         tx_packet->len = CDC_TX_SIZE;
 259                         usb_tx( CDC_TX_ENDPOINT, tx_packet );
 260                         tx_packet = NULL;
 261                 }
 262                 usb_cdc_transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
 263         }
 264         tx_noautoflush = 0;
 265         return 0;
 266 }
 267
 268 void usb_serial_flush_output()
 269 {
 270         if ( !usb_configuration )
 271                 return;
 272         tx_noautoflush = 1;
 273         if ( tx_packet )
 274         {
 275                 usb_cdc_transmit_flush_timer = 0;
 276                 tx_packet->len = tx_packet->index;
 277                 usb_tx( CDC_TX_ENDPOINT, tx_packet );
 278                 tx_packet = NULL;
 279         }
 280         else
 281         {
 282                 usb_packet_t *tx = usb_malloc();
 283                 if ( tx )
 284                 {
 285                         usb_cdc_transmit_flush_timer = 0;
 286                         usb_tx( CDC_TX_ENDPOINT, tx );
 287                 }
 288                 else
 289                 {
 290                         usb_cdc_transmit_flush_timer = 1;
 291                 }
 292         }
 293         tx_noautoflush = 0;
 294 }
 295
 296 void usb_serial_flush_callback()
 297 {
 298         if ( tx_noautoflush )
 299                 return;
 300         if ( tx_packet )
 301         {
 302                 tx_packet->len = tx_packet->index;
 303                 usb_tx( CDC_TX_ENDPOINT, tx_packet );
 304                 tx_packet = NULL;
 305         } else {
 306                 usb_packet_t *tx = usb_malloc();
 307                 if ( tx )
 308                 {
 309                         usb_tx( CDC_TX_ENDPOINT, tx );
 310                 }
 311                 else
 312                 {
 313                         usb_cdc_transmit_flush_timer = 1;
 314                 }
 315         }
 316 }
 317