Ross Squires / SoftSerial

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Fork of SoftSerial by Erik -

SoftSerial_rx.cpp@3:7238e9bb74d2, 2014-04-26 (annotated)

Committer:
Sissors
Date:
Sat Apr 26 16:35:20 2014 +0000
Revision:
3:7238e9bb74d2
Parent:
1:f8b4b764ace7
Child:
4:c010265ed202
And RX to 19200 (todo: a fast mode which is not interrupt based)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:8edaa7abe724 1 #include "SoftSerial.h"
Sissors 0:8edaa7abe724 2
Sissors 0:8edaa7abe724 3 int SoftSerial::_getc( void ) {
Sissors 1:f8b4b764ace7 4 while(!readable());
Sissors 1:f8b4b764ace7 5 out_valid = false;
Sissors 1:f8b4b764ace7 6 return out_buffer;
Sissors 1:f8b4b764ace7 7 }
Sissors 0:8edaa7abe724 8
Sissors 1:f8b4b764ace7 9 int SoftSerial::readable(void) {
Sissors 1:f8b4b764ace7 10 return out_valid;
Sissors 1:f8b4b764ace7 11 }
Sissors 1:f8b4b764ace7 12
Sissors 1:f8b4b764ace7 13 //Start receiving byte
Sissors 0:8edaa7abe724 14 void SoftSerial::rx_gpio_irq_handler(void) {
Sissors 3:7238e9bb74d2 15 rxout.attach_us(this, &SoftSerial::rx_handler, bit_period + (bit_period >> 1)); //Start reading first data byte
Sissors 1:f8b4b764ace7 16 rx->fall(NULL);
Sissors 1:f8b4b764ace7 17 rx_bit = 0;
Sissors 1:f8b4b764ace7 18 rx_error = false;
Sissors 0:8edaa7abe724 19 };
Sissors 1:f8b4b764ace7 20
Sissors 1:f8b4b764ace7 21 void SoftSerial::rx_handler(void) {
Sissors 3:7238e9bb74d2 22 if (!rx_bit)
Sissors 3:7238e9bb74d2 23 rxticker.attach_us(this, &SoftSerial::rx_handler, bit_period);
Sissors 3:7238e9bb74d2 24
Sissors 1:f8b4b764ace7 25 rx_bit++;
Sissors 1:f8b4b764ace7 26
Sissors 1:f8b4b764ace7 27 //Receive data
Sissors 1:f8b4b764ace7 28 int val = rx->read();
Sissors 1:f8b4b764ace7 29 if (rx_bit <= _bits) {
Sissors 1:f8b4b764ace7 30 read_buffer |= val << (rx_bit - 1);
Sissors 1:f8b4b764ace7 31 return;
Sissors 1:f8b4b764ace7 32 }
Sissors 1:f8b4b764ace7 33
Sissors 1:f8b4b764ace7 34 //Receive parity
Sissors 1:f8b4b764ace7 35 bool parity_count;
Sissors 1:f8b4b764ace7 36 if (rx_bit == _bits + 1) {
Sissors 1:f8b4b764ace7 37 switch (_parity) {
Sissors 1:f8b4b764ace7 38 case Forced1:
Sissors 1:f8b4b764ace7 39 if (val == 0)
Sissors 1:f8b4b764ace7 40 rx_error = true;
Sissors 1:f8b4b764ace7 41 return;
Sissors 1:f8b4b764ace7 42 case Forced0:
Sissors 1:f8b4b764ace7 43 if (val == 1)
Sissors 1:f8b4b764ace7 44 rx_error = true;
Sissors 1:f8b4b764ace7 45 return;
Sissors 1:f8b4b764ace7 46 case Even:
Sissors 1:f8b4b764ace7 47 case Odd:
Sissors 1:f8b4b764ace7 48 parity_count = val;
Sissors 1:f8b4b764ace7 49 for (int i = 0; i<_bits; i++) {
Sissors 1:f8b4b764ace7 50 if (((read_buffer >> i) & 0x01) == 1)
Sissors 1:f8b4b764ace7 51 parity_count = !parity_count;
Sissors 1:f8b4b764ace7 52 }
Sissors 1:f8b4b764ace7 53 if ((parity_count) && (_parity == Even))
Sissors 1:f8b4b764ace7 54 rx_error = true;
Sissors 1:f8b4b764ace7 55 if ((!parity_count) && (_parity == Odd))
Sissors 1:f8b4b764ace7 56 rx_error = true;
Sissors 1:f8b4b764ace7 57 return;
Sissors 1:f8b4b764ace7 58 }
Sissors 1:f8b4b764ace7 59 }
Sissors 1:f8b4b764ace7 60
Sissors 1:f8b4b764ace7 61 //Receive stop
Sissors 1:f8b4b764ace7 62 if (rx_bit < _bits + (bool)_parity + _stop_bits) {
Sissors 1:f8b4b764ace7 63 if (!val)
Sissors 1:f8b4b764ace7 64 rx_error = true;
Sissors 1:f8b4b764ace7 65 return;
Sissors 1:f8b4b764ace7 66 }
Sissors 1:f8b4b764ace7 67
Sissors 1:f8b4b764ace7 68 //The last stop bit
Sissors 1:f8b4b764ace7 69 if (!val)
Sissors 1:f8b4b764ace7 70 rx_error = true;
Sissors 1:f8b4b764ace7 71
Sissors 1:f8b4b764ace7 72 if (!rx_error) {
Sissors 1:f8b4b764ace7 73 out_valid = true;
Sissors 1:f8b4b764ace7 74 out_buffer = read_buffer;
Sissors 1:f8b4b764ace7 75 }
Sissors 1:f8b4b764ace7 76 read_buffer = 0;
Sissors 3:7238e9bb74d2 77 rxticker.detach();
Sissors 1:f8b4b764ace7 78 rx->fall(this, &SoftSerial::rx_gpio_irq_handler);
Sissors 1:f8b4b764ace7 79 }
Sissors 1:f8b4b764ace7 80