Tom Soulanille
An RTOS-friendly Serial interface Its primary benefit is that it never hogs the CPU. An amusing alternative to the traditional ring-bufferd interrupt-serviced systems, it uses short mbed-rtos queues to buffer characters to and from the UART, and a thread to service the transmitter. Short interrupt service routines enqueue received characters and signal the transmit thread when the transmitter is available. WARNING: Do not create RTOS-Serial objects before the RTOS is running! Put them inside your main() block or another function, not in the global initialization.
Dependents: Test_RDM880_rfid_reader
Diff: rtos_serial.cpp
- Revision:
- 0:0547c8bf304f
- Child:
- 1:5a66fddad7c4
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/rtos_serial.cpp Fri Oct 18 02:55:07 2013 +0000
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2013 Tom Soulanille
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "rtos_serial.h"
+
+//RTOS_Serial::tx_mail_t blah;
+
+RTOS_Serial::RTOS_Serial(PinName tx, PinName rx, const char *name)
+ : Serial(tx, rx, name)
+{
+ const PinName leds[] = {LED1,LED2,LED3,LED4};
+ ledp = new DigitalOut(leds[get_index()]);
+ tx_emitter_threadp = new Thread(tx_emitter, (void *) this);
+};
+
+Thread* RTOS_Serial::tx_tp[4] = { NULL, NULL, NULL, NULL };
+
+serial_t RTOS_Serial::get_serial() { return _serial; };
+
+int RTOS_Serial::get_index() { return _serial.index; }
+
+int RTOS_Serial::putc(int c) {
+ //return Serial::putc(c);
+ //if (tx_q.put((int *)c, osWaitForever) == osOK) return c; else return EOF;
+ int status;
+ if ( (status = tx_q.put((int *)c, osWaitForever)) == osOK) return c; else {
+ std::printf("tx_q.put() returned %d\r\n", status);
+ return EOF;
+ }
+}
+
+int RTOS_Serial::parent_putc(int c) {
+ return Serial::putc(c);
+}
+
+// class method
+void RTOS_Serial::UART0_TX_ISR(){
+ uint32_t IRR = LPC_UART0->IIR;
+ //tx_emitter_threadp->signal_set(0x1);
+ tx_tp[0]->signal_set(0x01);
+}
+
+// tx_emitter is a class method
+void RTOS_Serial::tx_emitter(void const *argument){
+ RTOS_Serial *sp = (RTOS_Serial *) argument;
+ osEvent evt;
+ while(true){
+#if 0
+ *(sp->ledp) = 0;
+ osDelay(200);
+ *(sp->ledp) = 1;
+ osDelay(200);
+#endif
+#if 1
+ evt = sp->tx_q.get();
+ if (evt.status == osEventMessage) {
+ //Thread::signal_wait(0x1);
+ *(sp->ledp) = 1;
+ sp->parent_putc(evt.value.v);
+ *(sp->ledp) = 0;
+ } else {
+ std::printf("tx_emitter() evt.status %d\n", evt.status);
+ }
+#endif
+ *(sp->ledp) = 0;
+ }
+}
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