Erik - / SoftSerial

Software serial, for when you are out of serial pins

Dependents:   BufferedSoftSerial neurGAI_Seeed_BLUETOOTH LPC-SD-35 ESP-WROOM-02_test ... more

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 }