Revision 0:064ba08b22ef, committed 2017-09-23

Comitter:

briandk

Date:

Sat Sep 23 21:01:23 2017 +0000

Commit message:

Comunicacion serial

Changed in this revision

diff -r 000000000000 -r 064ba08b22ef SoftSerial.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftSerial.cpp	Sat Sep 23 21:01:23 2017 +0000
@@ -0,0 +1,40 @@
+#include "SoftSerial.h"
+
+SoftSerial::SoftSerial(PinName TX, PinName RX, const char* name) {
+    tx_en = rx_en = false;
+    if (TX != NC) {
+        tx = new DigitalOut(TX);
+        tx_en = true;
+        tx->write(1);
+        tx_bit = -1;
+        txticker.attach(this, &SoftSerial::tx_handler);
+    }
+    if (RX != NC) {
+        rx = new InterruptIn(RX);
+        rx_en = true;
+        out_valid = false;
+        rxticker.attach(this, &SoftSerial::rx_handler);
+        rx->fall(this, &SoftSerial::rx_gpio_irq_handler);
+    }
+    
+    baud(9600);
+    format();
+}
+
+SoftSerial::~SoftSerial() {
+    if (tx_en)
+        delete(tx);
+    if (rx_en)
+        delete(rx);
+}
+
+void SoftSerial::baud(int baudrate) {
+    bit_period = 1000000 / baudrate;
+}
+
+void SoftSerial::format(int bits, Parity parity, int stop_bits) {
+    _bits = bits;
+    _parity = parity;
+    _stop_bits = stop_bits;
+    _total_bits = 1 + _bits + _stop_bits + (bool)_parity;
+}

diff -r 000000000000 -r 064ba08b22ef SoftSerial.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftSerial.h	Sat Sep 23 21:01:23 2017 +0000
@@ -0,0 +1,124 @@
+#ifndef SOFTSERIAL_H
+#define SOFTSERIAL_H
+
+#include "mbed.h"
+#include "SoftSerial_Ticker.h"
+/** A software serial implementation
+ *
+ */
+class SoftSerial: public Stream {
+
+public:
+    /**
+    * Constructor
+    *
+    * @param TX Name of the TX pin, NC for not connected
+    * @param RX Name of the RX pin, NC for not connected, must be capable of being InterruptIn
+    * @param name Name of the connection
+    */
+    SoftSerial(PinName TX, PinName RX, const char* name = NULL);
+    virtual ~SoftSerial();
+    
+    /** Set the baud rate of the serial port
+     *
+     *  @param baudrate The baudrate of the serial port (default = 9600).
+     */
+    void baud(int baudrate);
+
+    enum Parity {
+        None = 0,
+        Odd,
+        Even,
+        Forced1,
+        Forced0
+    };
+
+    enum IrqType {
+        RxIrq = 0,
+        TxIrq
+    };
+
+    /** Set the transmission format used by the serial port
+     *
+     *  @param bits The number of bits in a word (default = 8)
+     *  @param parity The parity used (SerialBase::None, SerialBase::Odd, SerialBase::Even, SerialBase::Forced1, SerialBase::Forced0; default = SerialBase::None)
+     *  @param stop The number of stop bits (default = 1)
+     */
+    void format(int bits=8, Parity parity=SoftSerial::None, int stop_bits=1);
+
+    /** Determine if there is a character available to read
+     *
+     *  @returns
+     *    1 if there is a character available to read,
+     *    0 otherwise
+     */
+    int readable();
+
+    /** Determine if there is space available to write a character
+     *
+     *  @returns
+     *    1 if there is space to write a character,
+     *    0 otherwise
+     */
+    int writeable();
+
+    /** Attach a function to call whenever a serial interrupt is generated
+     *
+     *  @param fptr A pointer to a void function, or 0 to set as none
+     *  @param type Which serial interrupt to attach the member function to (Seriall::RxIrq for receive, TxIrq for transmit buffer empty)
+     */
+    void attach(void (*fptr)(void), IrqType type=RxIrq) {
+        fpointer[type].attach(fptr);
+    }
+
+    /** Attach a member function to call whenever a serial interrupt is generated
+     *
+     *  @param tptr pointer to the object to call the member function on
+     *  @param mptr pointer to the member function to be called
+     *  @param type Which serial interrupt to attach the member function to (Seriall::RxIrq for receive, TxIrq for transmit buffer empty)
+     */
+    template<typename T>
+    void attach(T* tptr, void (T::*mptr)(void), IrqType type=RxIrq) {
+        fpointer[type].attach(tptr, mptr);
+    }
+
+    /** Generate a break condition on the serial line
+     */
+    void send_break();
+
+protected:
+    DigitalOut *tx;
+    InterruptIn *rx;
+    
+    bool tx_en, rx_en;
+    int bit_period;
+    int _bits, _stop_bits, _total_bits;
+    Parity _parity;
+    
+    FunctionPointer fpointer[2];
+    
+    //rx
+    void rx_gpio_irq_handler(void);
+    void rx_handler(void);
+    int read_buffer, rx_bit;
+    volatile int out_buffer;
+    volatile bool out_valid;
+    bool rx_error;
+    FlexTicker rxticker;
+    
+    //tx
+    void tx_handler(void);
+    void prepare_tx(int c);
+    FlexTicker txticker;
+    int _char;
+    volatile int tx_bit;
+    
+    
+    
+    virtual int _getc();
+    virtual int _putc(int c);
+};
+
+
+#endif
+

diff -r 000000000000 -r 064ba08b22ef SoftSerial_Ticker.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftSerial_Ticker.h	Sat Sep 23 21:01:23 2017 +0000
@@ -0,0 +1,38 @@
+//A modified version of the regular ticker/timeout libraries to allow us to do timeout without losing accuracy
+
+#ifndef FLEXTICKER_H
+#define FLEXTICKER_H
+
+#include "mbed.h"
+
+class FlexTicker: public TimerEvent {
+    public:
+    template<typename T>
+    void attach(T* tptr, void (T::*mptr)(void)) {
+        _function.attach(tptr, mptr);
+    }
+ 
+    /** Detach the function
+     */
+    void detach() {
+        remove();
+    }
+    
+    void setNext(int delay) {
+        insert(event.timestamp + delay);
+    }
+    
+    void prime(void) {
+        event.timestamp = us_ticker_read();
+    }
+ 
+protected:
+    virtual void handler() {
+        _function.call();
+    }
+ 
+    unsigned int _delay;
+    FunctionPointer _function;
+};
+
+#endif
\ No newline at end of file

diff -r 000000000000 -r 064ba08b22ef SoftSerial_rx.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftSerial_rx.cpp	Sat Sep 23 21:01:23 2017 +0000
@@ -0,0 +1,84 @@
+#include "SoftSerial.h"
+
+uint32_t overhead_us = 200 * 1000000 / SystemCoreClock;         //Random estimation of the overhead of mbed libs, makes slow devices like LPC812 @ 12MHz perform better
+
+int SoftSerial::_getc( void ) {
+    while(!readable());
+    out_valid = false;
+    return out_buffer;
+}
+
+int SoftSerial::readable(void) {
+    return out_valid;
+}
+
+//Start receiving byte
+void SoftSerial::rx_gpio_irq_handler(void) {
+    rxticker.prime();
+    rxticker.setNext(bit_period + (bit_period >> 1) - overhead_us);
+    rx->fall(NULL);
+    rx_bit = 0;
+    rx_error = false;
+};    
+
+void SoftSerial::rx_handler(void) {
+    //Receive data
+    int val = rx->read();
+ 
+    rxticker.setNext(bit_period);
+    rx_bit++;
+    
+    
+    if (rx_bit <= _bits) {
+        read_buffer |= val << (rx_bit - 1);
+        return;
+    }
+    
+    //Receive parity
+    bool parity_count;
+    if (rx_bit == _bits + 1) {
+        switch (_parity) {
+            case Forced1:
+                if (val == 0)
+                    rx_error = true;
+                return;
+            case Forced0:
+                if (val == 1)
+                    rx_error = true;
+                return;
+            case Even:
+            case Odd:
+                parity_count = val;
+                for (int i = 0; i<_bits; i++) {
+                    if (((read_buffer >> i) & 0x01) == 1)
+                        parity_count = !parity_count;
+                }
+                if ((parity_count) && (_parity == Even))
+                    rx_error = true;
+                if ((!parity_count) && (_parity == Odd))
+                    rx_error = true;
+                return;
+        }
+    }
+    
+    //Receive stop
+    if (rx_bit < _bits + (bool)_parity + _stop_bits) {
+        if (!val)
+            rx_error = true;
+        return;
+    }    
+    
+    //The last stop bit
+    if (!val)
+        rx_error = true;
+    
+    if (!rx_error) {
+        out_valid = true;
+        out_buffer = read_buffer;
+        fpointer[RxIrq].call();
+    }
+    read_buffer = 0;
+    rxticker.detach(); 
+    rx->fall(this, &SoftSerial::rx_gpio_irq_handler);
+}
+

diff -r 000000000000 -r 064ba08b22ef SoftSerial_tx.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftSerial_tx.cpp	Sat Sep 23 21:01:23 2017 +0000
@@ -0,0 +1,80 @@
+#include "SoftSerial.h"
+
+int SoftSerial::_putc(int c)
+{
+    while(!writeable());
+    prepare_tx(c);
+    tx_bit = 0;
+    txticker.prime();
+    tx_handler();
+    return 0;
+}
+
+void SoftSerial::send_break(void) {
+    while(!writeable());
+    tx_bit = 0;         //Just to make sure it appears as non-writable to other threads/IRQs
+    tx->write(0);
+    wait_us((bit_period * _total_bits * 3) / 2);
+    tx->write(1);
+    tx_bit = -1;
+}
+
+int SoftSerial::writeable(void)
+{
+    if (!tx_en)
+        return false;
+    if (tx_bit == -1)
+        return true;
+    return false;
+}
+
+void SoftSerial::tx_handler(void)
+{
+    if (tx_bit == _total_bits) {
+        tx_bit = -1;
+        fpointer[TxIrq].call();
+        return;
+    }
+
+    //Flip output
+    int cur_out = tx->read();
+    tx->write(!cur_out);
+
+    //Calculate when to do it again
+    int count = bit_period;
+    tx_bit++;
+    while(((_char >> tx_bit) & 0x01) == !cur_out) {
+        count+=bit_period;
+        tx_bit++;
+    }
+
+    txticker.setNext(count);
+}
+
+void SoftSerial::prepare_tx(int c)
+{
+    _char = c << 1;
+
+    bool parity;
+    switch (_parity) {
+        case Forced1:
+            _char |= 1 << (_bits + 1);
+        case Even:
+            parity = false;
+            for (int i = 0; i<_bits; i++) {
+                if (((_char >> i) & 0x01) == 1)
+                    parity = !parity;
+            }
+            _char |= parity << (_bits + 1);
+        case Odd:
+            parity = true;
+            for (int i = 0; i<_bits; i++) {
+                if (((_char >> i) & 0x01) == 1)
+                    parity = !parity;
+            }
+            _char |= parity << (_bits + 1);
+    }
+    
+    _char |= 0xFFFF << (1 + _bits + (bool)_parity);
+    _char &= ~(1<<_total_bits);
+}