João Sousa / SoftSerial1

Software Serial lib

Dependents:   BufferedSoftSerial

Fork of SoftSerial by João Sousa

SoftSerial_rx.cpp@11:2d4a883a687a, 2015-05-16 (annotated)

Committer:
jotaemesousa
Date:
Sat May 16 21:40:11 2015 +0000
Revision:
11:2d4a883a687a
Parent:
10:236fce2e5b8c 
ENC sendong message

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:8edaa7abe724 1 #include "SoftSerial.h"
Sissors 0:8edaa7abe724 2
jotaemesousa 11:2d4a883a687a 3 DigitalOut myled(LED1);
Sissors 10:236fce2e5b8c 4 uint32_t overhead_us = 200 * 1000000 / SystemCoreClock; //Random estimation of the overhead of mbed libs, makes slow devices like LPC812 @ 12MHz perform better
Sissors 10:236fce2e5b8c 5
Sissors 0:8edaa7abe724 6 int SoftSerial::_getc( void ) {
Sissors 1:f8b4b764ace7 7 while(!readable());
Sissors 1:f8b4b764ace7 8 out_valid = false;
Sissors 1:f8b4b764ace7 9 return out_buffer;
Sissors 1:f8b4b764ace7 10 }
Sissors 0:8edaa7abe724 11
Sissors 1:f8b4b764ace7 12 int SoftSerial::readable(void) {
Sissors 1:f8b4b764ace7 13 return out_valid;
Sissors 1:f8b4b764ace7 14 }
Sissors 1:f8b4b764ace7 15
Sissors 1:f8b4b764ace7 16 //Start receiving byte
Sissors 0:8edaa7abe724 17 void SoftSerial::rx_gpio_irq_handler(void) {
Sissors 6:517082212c00 18 rxticker.prime();
Sissors 10:236fce2e5b8c 19 rxticker.setNext(bit_period + (bit_period >> 1) - overhead_us);
Sissors 1:f8b4b764ace7 20 rx->fall(NULL);
Sissors 1:f8b4b764ace7 21 rx_bit = 0;
Sissors 1:f8b4b764ace7 22 rx_error = false;
jotaemesousa 11:2d4a883a687a 23 myled = 1;
Sissors 0:8edaa7abe724 24 };
Sissors 1:f8b4b764ace7 25
Sissors 1:f8b4b764ace7 26 void SoftSerial::rx_handler(void) {
Sissors 10:236fce2e5b8c 27 //Receive data
jotaemesousa 11:2d4a883a687a 28 myled = 0;
Sissors 10:236fce2e5b8c 29 int val = rx->read();
Sissors 10:236fce2e5b8c 30
Sissors 6:517082212c00 31 rxticker.setNext(bit_period);
Sissors 1:f8b4b764ace7 32 rx_bit++;
Sissors 1:f8b4b764ace7 33
Sissors 10:236fce2e5b8c 34
Sissors 1:f8b4b764ace7 35 if (rx_bit <= _bits) {
Sissors 1:f8b4b764ace7 36 read_buffer |= val << (rx_bit - 1);
Sissors 1:f8b4b764ace7 37 return;
Sissors 1:f8b4b764ace7 38 }
Sissors 1:f8b4b764ace7 39
Sissors 1:f8b4b764ace7 40 //Receive parity
Sissors 1:f8b4b764ace7 41 bool parity_count;
Sissors 1:f8b4b764ace7 42 if (rx_bit == _bits + 1) {
Sissors 1:f8b4b764ace7 43 switch (_parity) {
Sissors 1:f8b4b764ace7 44 case Forced1:
Sissors 1:f8b4b764ace7 45 if (val == 0)
Sissors 1:f8b4b764ace7 46 rx_error = true;
Sissors 1:f8b4b764ace7 47 return;
Sissors 1:f8b4b764ace7 48 case Forced0:
Sissors 1:f8b4b764ace7 49 if (val == 1)
Sissors 1:f8b4b764ace7 50 rx_error = true;
Sissors 1:f8b4b764ace7 51 return;
Sissors 1:f8b4b764ace7 52 case Even:
Sissors 1:f8b4b764ace7 53 case Odd:
Sissors 1:f8b4b764ace7 54 parity_count = val;
Sissors 1:f8b4b764ace7 55 for (int i = 0; i<_bits; i++) {
Sissors 1:f8b4b764ace7 56 if (((read_buffer >> i) & 0x01) == 1)
Sissors 1:f8b4b764ace7 57 parity_count = !parity_count;
Sissors 1:f8b4b764ace7 58 }
Sissors 1:f8b4b764ace7 59 if ((parity_count) && (_parity == Even))
Sissors 1:f8b4b764ace7 60 rx_error = true;
Sissors 1:f8b4b764ace7 61 if ((!parity_count) && (_parity == Odd))
Sissors 1:f8b4b764ace7 62 rx_error = true;
Sissors 1:f8b4b764ace7 63 return;
Sissors 1:f8b4b764ace7 64 }
Sissors 1:f8b4b764ace7 65 }
Sissors 1:f8b4b764ace7 66
Sissors 1:f8b4b764ace7 67 //Receive stop
Sissors 1:f8b4b764ace7 68 if (rx_bit < _bits + (bool)_parity + _stop_bits) {
Sissors 1:f8b4b764ace7 69 if (!val)
Sissors 1:f8b4b764ace7 70 rx_error = true;
Sissors 1:f8b4b764ace7 71 return;
Sissors 1:f8b4b764ace7 72 }
Sissors 1:f8b4b764ace7 73
Sissors 1:f8b4b764ace7 74 //The last stop bit
Sissors 1:f8b4b764ace7 75 if (!val)
Sissors 1:f8b4b764ace7 76 rx_error = true;
Sissors 1:f8b4b764ace7 77
Sissors 1:f8b4b764ace7 78 if (!rx_error) {
Sissors 1:f8b4b764ace7 79 out_valid = true;
Sissors 1:f8b4b764ace7 80 out_buffer = read_buffer;
Sissors 4:c010265ed202 81 fpointer[RxIrq].call();
Sissors 1:f8b4b764ace7 82 }
Sissors 1:f8b4b764ace7 83 read_buffer = 0;
Sissors 3:7238e9bb74d2 84 rxticker.detach();
Sissors 1:f8b4b764ace7 85 rx->fall(this, &SoftSerial::rx_gpio_irq_handler);
Sissors 1:f8b4b764ace7 86 }
Sissors 1:f8b4b764ace7 87