libraries/AP_RCProtocol/SoftSerial.h

   1 /*
   2  * This file is free software: you can redistribute it and/or modify it
   3  * under the terms of the GNU General Public License as published by the
   4  * Free Software Foundation, either version 3 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * This file is distributed in the hope that it will be useful, but
   8  * WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  10  * See the GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License along
  13  * with this program.  If not, see <http://www.gnu.org/licenses/>.
  14  */
  15
  16 #pragma once
  17
  18 #include "AP_RCProtocol.h"
  19
  20 class SoftSerial {
  21 public:
  22     enum serial_config {
  23         SERIAL_CONFIG_8N1  = 0, // DSM, SRXL etc, 8 bit, no parity, 1 stop bit
  24         SERIAL_CONFIG_8E2I = 1, // SBUS, 8 bit, even parity, 2 stop bits, inverted
  25         SERIAL_CONFIG_8N1I = 2, // FPort inverted, 8 bit, no parity, 1 stop bit
  26     };
  27
  28     SoftSerial(uint32_t baudrate, enum serial_config config);
  29     bool process_pulse(uint32_t width_s0, uint32_t width_s1, uint8_t &b);
  30
  31     // get timestamp of the last byte
  32     uint32_t get_byte_timestamp_us(void) const {
  33         return byte_timestamp_us;
  34     }
  35
  36     uint32_t baud() const { return baudrate; }
  37
  38 private:
  39     const uint32_t baudrate;
  40     const uint8_t half_bit; // width of half a bit in microseconds
  41     const enum serial_config config;
  42
  43     uint8_t data_width;
  44     uint8_t byte_width;
  45     uint16_t stop_mask;
  46     uint32_t timestamp_us;
  47     uint32_t byte_timestamp_us;
  48
  49     struct {
  50         uint32_t byte;
  51         uint16_t bit_ofs;
  52     } state;
  53 };