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 2013-2014
   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 == 48000000
  61   #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 428)
  62 #elif F_CPU == 24000000
  63   #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 262)
  64 #endif
  65
  66
  67
  68 // ----- Variables -----
  69
  70 // serial port settings (baud rate, control signals, etc) set
  71 // by the PC.  These are ignored, but kept in RAM.
  72 volatile uint8_t usb_cdc_line_coding[7] = { 0x00, 0xE1, 0x00, 0x00, 0x00, 0x00, 0x08 };
  73 volatile uint8_t usb_cdc_line_rtsdtr = 0;
  74 volatile uint8_t usb_cdc_transmit_flush_timer = 0;
  75
  76 static usb_packet_t *rx_packet = NULL;
  77 static usb_packet_t *tx_packet = NULL;
  78 static volatile uint8_t tx_noautoflush = 0;
  79
  80 // When we've suffered the transmit timeout, don't wait again until the computer
  81 // begins accepting data.  If no software is running to receive, we'll just discard
  82 // data as rapidly as Serial.print() can generate it, until there's something to
  83 // actually receive it.
  84 static uint8_t transmit_previous_timeout = 0;
  85
  86
  87
  88 // ----- Functions -----
  89
  90 // get the next character, or -1 if nothing received
  91 int usb_serial_getchar()
  92 {
  93         unsigned int i;
  94         int c;
  95
  96         if ( !rx_packet )
  97         {
  98                 if ( !usb_configuration )
  99                         return -1;
 100                 rx_packet = usb_rx( CDC_RX_ENDPOINT );
 101                 if ( !rx_packet )
 102                         return -1;
 103         }
 104         i = rx_packet->index;
 105         c = rx_packet->buf[i++];
 106         if ( i >= rx_packet->len )
 107         {
 108                 usb_free( rx_packet );
 109                 rx_packet = NULL;
 110         }
 111         else
 112         {
 113                 rx_packet->index = i;
 114         }
 115         return c;
 116 }
 117
 118 // peek at the next character, or -1 if nothing received
 119 int usb_serial_peekchar()
 120 {
 121         if ( !rx_packet )
 122         {
 123                 if ( !usb_configuration )
 124                         return -1;
 125                 rx_packet = usb_rx( CDC_RX_ENDPOINT );
 126                 if ( !rx_packet )
 127                         return -1;
 128         }
 129         if ( !rx_packet )
 130                 return -1;
 131         return rx_packet->buf[ rx_packet->index ];
 132 }
 133
 134 // number of bytes available in the receive buffer
 135 int usb_serial_available()
 136 {
 137         int count = usb_rx_byte_count( CDC_RX_ENDPOINT );
 138         if ( rx_packet )
 139                 count += rx_packet->len - rx_packet->index;
 140         return count;
 141 }
 142
 143 // read a block of bytes to a buffer
 144 int usb_serial_read( void *buffer, uint32_t size )
 145 {
 146         uint8_t *p = (uint8_t *)buffer;
 147         uint32_t qty, count=0;
 148
 149         while ( size )
 150         {
 151                 if ( !usb_configuration )
 152                         break;
 153                 if ( !rx_packet )
 154                 {
 155                         rx:
 156                                 rx_packet = usb_rx(CDC_RX_ENDPOINT);
 157                                 if ( !rx_packet )
 158                                         break;
 159                                 if ( rx_packet->len == 0 )
 160                                 {
 161                                         usb_free(rx_packet);
 162                                         goto rx;
 163                                 }
 164                 }
 165                 qty = rx_packet->len - rx_packet->index;
 166                 if ( qty > size )
 167                         qty = size;
 168                 memcpy( p, rx_packet->buf + rx_packet->index, qty );
 169                 p += qty;
 170                 count += qty;
 171                 size -= qty;
 172                 rx_packet->index += qty;
 173                 if ( rx_packet->index >= rx_packet->len )
 174                 {
 175                         usb_free( rx_packet );
 176                         rx_packet = NULL;
 177                 }
 178         }
 179         return count;
 180 }
 181
 182 // discard any buffered input
 183 void usb_serial_flush_input()
 184 {
 185         usb_packet_t *rx;
 186
 187         if ( !usb_configuration )
 188                 return;
 189         if ( rx_packet )
 190         {
 191                 usb_free( rx_packet );
 192                 rx_packet = NULL;
 193         }
 194         while (1)
 195         {
 196                 rx = usb_rx( CDC_RX_ENDPOINT );
 197                 if ( !rx )
 198                         break;
 199                 usb_free( rx );
 200         }
 201 }
 202
 203 // transmit a character.  0 returned on success, -1 on error
 204 int usb_serial_putchar( uint8_t c )
 205 {
 206         return usb_serial_write( &c, 1 );
 207 }
 208
 209 int usb_serial_write( const void *buffer, uint32_t size )
 210 {
 211         uint32_t len;
 212         uint32_t wait_count;
 213         const uint8_t *src = (const uint8_t *)buffer;
 214         uint8_t *dest;
 215
 216         tx_noautoflush = 1;
 217         while ( size > 0 )
 218         {
 219                 if ( !tx_packet )
 220                 {
 221                         wait_count = 0;
 222                         while ( 1 )
 223                         {
 224                                 if ( !usb_configuration )
 225                                 {
 226                                         tx_noautoflush = 0;
 227                                         return -1;
 228                                 }
 229                                 if ( usb_tx_packet_count( CDC_TX_ENDPOINT ) < TX_PACKET_LIMIT )
 230                                 {
 231                                         tx_noautoflush = 1;
 232                                         tx_packet = usb_malloc();
 233                                         if ( tx_packet )
 234                                                 break;
 235                                         tx_noautoflush = 0;
 236                                 }
 237                                 if ( ++wait_count > TX_TIMEOUT || transmit_previous_timeout )
 238                                 {
 239                                         transmit_previous_timeout = 1;
 240                                         return -1;
 241                                 }
 242                                 yield();
 243                         }
 244                 }
 245                 transmit_previous_timeout = 0;
 246                 len = CDC_TX_SIZE - tx_packet->index;
 247                 if ( len > size )
 248                         len = size;
 249                 dest = tx_packet->buf + tx_packet->index;
 250                 tx_packet->index += len;
 251                 size -= len;
 252                 while ( len-- > 0 )
 253                         *dest++ = *src++;
 254                 if ( tx_packet->index >= CDC_TX_SIZE )
 255                 {
 256                         tx_packet->len = CDC_TX_SIZE;
 257                         usb_tx( CDC_TX_ENDPOINT, tx_packet );
 258                         tx_packet = NULL;
 259                 }
 260                 usb_cdc_transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
 261         }
 262         tx_noautoflush = 0;
 263         return 0;
 264 }
 265
 266 void usb_serial_flush_output()
 267 {
 268         if ( !usb_configuration )
 269                 return;
 270         tx_noautoflush = 1;
 271         if ( tx_packet )
 272         {
 273                 usb_cdc_transmit_flush_timer = 0;
 274                 tx_packet->len = tx_packet->index;
 275                 usb_tx( CDC_TX_ENDPOINT, tx_packet );
 276                 tx_packet = NULL;
 277         }
 278         else
 279         {
 280                 usb_packet_t *tx = usb_malloc();
 281                 if ( tx )
 282                 {
 283                         usb_cdc_transmit_flush_timer = 0;
 284                         usb_tx( CDC_TX_ENDPOINT, tx );
 285                 }
 286                 else
 287                 {
 288                         usb_cdc_transmit_flush_timer = 1;
 289                 }
 290         }
 291         tx_noautoflush = 0;
 292 }
 293
 294 void usb_serial_flush_callback()
 295 {
 296         if ( tx_noautoflush )
 297                 return;
 298         if ( tx_packet )
 299         {
 300                 tx_packet->len = tx_packet->index;
 301                 usb_tx( CDC_TX_ENDPOINT, tx_packet );
 302                 tx_packet = NULL;
 303         } else {
 304                 usb_packet_t *tx = usb_malloc();
 305                 if ( tx )
 306                 {
 307                         usb_tx( CDC_TX_ENDPOINT, tx );
 308                 }
 309                 else
 310                 {
 311                         usb_cdc_transmit_flush_timer = 1;
 312                 }
 313         }
 314 }
 315