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_tx.cpp@6:517082212c00, 2014-04-27 (annotated)

Committer:
Sissors
Date:
Sun Apr 27 08:33:17 2014 +0000
Revision:
6:517082212c00
Parent:
4:c010265ed202
Child:
7:7de3e1019e23
Added custom ticker lib to allow for baudrate up to 57600

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:8edaa7abe724 1 #include "SoftSerial.h"
Sissors 0:8edaa7abe724 2
Sissors 2:9e01a38606b4 3 int SoftSerial::_putc(int c)
Sissors 2:9e01a38606b4 4 {
Sissors 0:8edaa7abe724 5 while(!writeable());
Sissors 2:9e01a38606b4 6 prepare_tx(c);
Sissors 0:8edaa7abe724 7 tx_bit = 0;
Sissors 6:517082212c00 8 txticker.prime();
Sissors 0:8edaa7abe724 9 tx_handler();
Sissors 0:8edaa7abe724 10 return 0;
Sissors 2:9e01a38606b4 11 }
Sissors 0:8edaa7abe724 12
Sissors 2:9e01a38606b4 13 int SoftSerial::writeable(void)
Sissors 2:9e01a38606b4 14 {
Sissors 0:8edaa7abe724 15 if (!tx_en)
Sissors 0:8edaa7abe724 16 return false;
Sissors 0:8edaa7abe724 17 if (tx_bit == -1)
Sissors 0:8edaa7abe724 18 return true;
Sissors 0:8edaa7abe724 19 return false;
Sissors 0:8edaa7abe724 20 }
Sissors 0:8edaa7abe724 21
Sissors 2:9e01a38606b4 22 void SoftSerial::tx_handler(void)
Sissors 2:9e01a38606b4 23 {
Sissors 2:9e01a38606b4 24 if (tx_bit == _total_bits) {
Sissors 0:8edaa7abe724 25 tx_bit = -1;
Sissors 4:c010265ed202 26 fpointer[TxIrq].call();
Sissors 0:8edaa7abe724 27 return;
Sissors 0:8edaa7abe724 28 }
Sissors 2:9e01a38606b4 29
Sissors 0:8edaa7abe724 30 //Flip output
Sissors 0:8edaa7abe724 31 int cur_out = tx->read();
Sissors 0:8edaa7abe724 32 tx->write(!cur_out);
Sissors 2:9e01a38606b4 33
Sissors 0:8edaa7abe724 34 //Calculate when to do it again
Sissors 0:8edaa7abe724 35 int count = bit_period;
Sissors 0:8edaa7abe724 36 tx_bit++;
Sissors 2:9e01a38606b4 37 while(((_char >> tx_bit) & 0x01) == !cur_out) {
Sissors 0:8edaa7abe724 38 count+=bit_period;
Sissors 0:8edaa7abe724 39 tx_bit++;
Sissors 0:8edaa7abe724 40 }
Sissors 2:9e01a38606b4 41
Sissors 6:517082212c00 42 txticker.setNext(count);
Sissors 0:8edaa7abe724 43 }
Sissors 0:8edaa7abe724 44
Sissors 2:9e01a38606b4 45 void SoftSerial::prepare_tx(int c)
Sissors 2:9e01a38606b4 46 {
Sissors 2:9e01a38606b4 47 _char = c << 1;
Sissors 2:9e01a38606b4 48
Sissors 2:9e01a38606b4 49 bool parity;
Sissors 2:9e01a38606b4 50 switch (_parity) {
Sissors 2:9e01a38606b4 51 case Forced1:
Sissors 2:9e01a38606b4 52 _char |= 1 << (_bits + 1);
Sissors 2:9e01a38606b4 53 case Even:
Sissors 2:9e01a38606b4 54 parity = false;
Sissors 2:9e01a38606b4 55 for (int i = 0; i<_bits; i++) {
Sissors 2:9e01a38606b4 56 if (((_char >> i) & 0x01) == 1)
Sissors 2:9e01a38606b4 57 parity = !parity;
Sissors 2:9e01a38606b4 58 }
Sissors 2:9e01a38606b4 59 _char |= parity << (_bits + 1);
Sissors 2:9e01a38606b4 60 case Odd:
Sissors 2:9e01a38606b4 61 parity = true;
Sissors 2:9e01a38606b4 62 for (int i = 0; i<_bits; i++) {
Sissors 2:9e01a38606b4 63 if (((_char >> i) & 0x01) == 1)
Sissors 2:9e01a38606b4 64 parity = !parity;
Sissors 2:9e01a38606b4 65 }
Sissors 2:9e01a38606b4 66 _char |= parity << (_bits + 1);
Sissors 0:8edaa7abe724 67 }
Sissors 0:8edaa7abe724 68
Sissors 2:9e01a38606b4 69 _char |= 0xFFFF << (1 + _bits + (bool)_parity);
Sissors 2:9e01a38606b4 70 _char &= ~(1<<_total_bits);
Sissors 2:9e01a38606b4 71 }