Diff: BufferedSoftSerial.cpp

Revision:

6:4e3e18b41ea6

Child:

9:5b069a1896f9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/BufferedSoftSerial.cpp	Sat Apr 26 20:55:42 2014 +0000
@@ -0,0 +1,148 @@
+/**
+ * @file    BufferedSoftSerial.cpp
+ * @brief   Software Buffer - Extends mbed Serial functionallity adding irq driven TX and RX
+ * @author  sam grove
+ * @version 1.0
+ * @see
+ *
+ * Copyright (c) 2013
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "BufferedSoftSerial.h"
+#include <stdarg.h>
+
+BufferedSoftSerial::BufferedSoftSerial(PinName tx, PinName rx, const char* name)
+    : SoftSerial(tx, rx, name)
+{
+    SoftSerial::attach(this, &BufferedSoftSerial::rxIrq, SoftSerial::RxIrq);
+
+    return;
+}
+
+BufferedSoftSerial::~BufferedSoftSerial(void)
+{
+    SoftSerial::attach(NULL, SoftSerial::RxIrq);
+    SoftSerial::attach(NULL, SoftSerial::TxIrq);
+
+    return;
+}
+
+int BufferedSoftSerial::readable(void)
+{
+    return _rxbuf.available();  // note: look if things are in the buffer
+}
+
+int BufferedSoftSerial::writeable(void)
+{
+    return 1;   // buffer allows overwriting by design, always true
+}
+
+int BufferedSoftSerial::getc(void)
+{
+    return _rxbuf;
+}
+
+int BufferedSoftSerial::putc(int c)
+{
+    _txbuf = (char)c;
+    BufferedSoftSerial::prime();
+
+    return c;
+}
+
+int BufferedSoftSerial::puts(const char *s)
+{
+    const char* ptr = s;
+
+    while(*(ptr) != 0) {
+        _txbuf = *(ptr++);
+    }
+    _txbuf = '\n';  // done per puts definition
+    BufferedSoftSerial::prime();
+
+    return (ptr - s) + 1;
+}
+
+int BufferedSoftSerial::printf(const char* format, ...)
+{
+    char buf[256] = {0};
+    int r = 0;
+
+    va_list arg;
+    va_start(arg, format);
+    r = vsprintf(buf, format, arg);
+    // this may not hit the heap but should alert the user anyways
+    if(r > sizeof(buf)) {
+        error("%s %d buffer overwrite!\n", __FILE__, __LINE__);
+    }
+    va_end(arg);
+    r = BufferedSoftSerial::write(buf, r);
+
+    return r;
+}
+
+ssize_t BufferedSoftSerial::write(const void *s, size_t length)
+{
+    const char* ptr = (const char*)s;
+    const char* end = ptr + length;
+
+    while (ptr != end) {
+        _txbuf = *(ptr++);
+    }
+    BufferedSoftSerial::prime();
+
+    return ptr - (const char*)s;
+}
+
+
+void BufferedSoftSerial::rxIrq(void)
+{
+    // read from the peripheral and make sure something is available
+    if(SoftSerial::readable()) {
+        _rxbuf = _getc(); // if so load them into a buffer
+    }
+
+    return;
+}
+
+void BufferedSoftSerial::txIrq(void)
+{
+    // see if there is room in the hardware fifo and if something is in the software fifo
+    while(SoftSerial::writeable()) {
+        if(_txbuf.available()) {
+            _putc((int)_txbuf.get());
+        } else {
+            // disable the TX interrupt when there is nothing left to send
+            SoftSerial::attach(NULL, SoftSerial::TxIrq);
+            break;
+        }
+    }
+
+    return;
+}
+
+void BufferedSoftSerial::prime(void)
+{
+    // if already busy then the irq will pick this up
+    if(SoftSerial::writeable()) {
+        SoftSerial::attach(NULL, SoftSerial::TxIrq);    // make sure not to cause contention in the irq
+        BufferedSoftSerial::txIrq();                // only write to hardware in one place
+        SoftSerial::attach(this, &BufferedSoftSerial::txIrq, SoftSerial::TxIrq);
+    }
+
+    return;
+}
+
+