Diff: main.cpp

Revision:

0:1b9561cd1c36

Child:

1:6f8ffb2c2dd7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Mar 17 16:38:46 2017 +0000
@@ -0,0 +1,145 @@
+/*
+ * A demo showing how to use CAN bus and the CANMsg library's << (append) and the >> (extract) operators
+ *
+ * Two affordable (less than $3 on ebay) STM32F103C8T6 boards (20kB SRAM, 64kB Flash),
+ * are connected to the same CAN bus via transceivers (MCP2551 or TJA1040, or etc.).
+ * CAN transceivers are not part of NUCLEO boards, therefore must be added by you.
+ * Remember also that CAN bus (even a short one) must be terminated with 120 Ohm resitors at both ends.
+ * In this demo, the mbed board is transmitting two data items to the CAN bus.
+ *   counter: uint_8 value (one byte).
+ *   voltage: floating point value (four bytes).
+ * So the total length of payload data is five bytes.
+ * The "<<" (append) operator is used to add data to the CAN message.
+ * If a CAN message is received its ID is checked. If there is match with the awaited ID
+ * then data is extracted from the CAN message using the ">>" (extract) operator.
+ *
+ * The usage of "<<" and ">>" operators is similar to the C++ io-stream ones.
+ * Data length of CAN message is automatically updated when using "<<" or ">>" operators.  
+ *
+ * For schematic see the wiki page <https://developer.mbed.org/users/hudakz/code/CAN_Hello/>
+ *
+ * NOTE: If you'd like to use an STM32F103C8T6 board uncomment line 28
+ *
+ * The same code is used for both NUCLEO boards, but:
+ *      For board #1 compile the example without any change.
+ *      For board #2 comment out line 27 before compilation
+ *
+ * Once the binaries have been downloaded to the boards reset board #1.
+ *
+ */
+#define BOARD1                  1   // comment out this line when compiling for board #2
+//#define TARGET_STM32F103C8T6    1   // uncomment this line when using STM32F103C8T6 boards!
+
+#if defined(TARGET_STM32F103C8T6)
+#include "stm32f103c8t6.h"
+#define LED_PIN PC_13
+const int           OFF = 1;
+const int           ON = 0;
+#else
+#define LED_PIN LED1
+const int           OFF = 0;
+const int           ON = 1;
+#endif
+#if defined(BOARD1)
+const unsigned int  RX_ID = 0x100;
+const unsigned int  TX_ID = 0x101;
+#else
+const unsigned int  RX_ID = 0x101;
+const unsigned int  TX_ID = 0x100;
+#endif
+
+#include "mbed.h"
+#include "CANMsg.h"
+
+Serial              pc(USBTX, USBRX);
+CAN                 can(PA_11, PA_12);    // CAN Rx pin name, CAN Tx pin name
+CANMsg              rxMsg;
+CANMsg              txMsg;
+DigitalOut          led(LED_PIN);
+Timer               timer;
+uint8_t             counter = 0;
+AnalogIn            analogIn(A0);
+float               voltage;
+
+/**
+ * @brief   Prints CAN msg to PC's serial terminal
+ * @note}
+ * @param   CANMess to print
+ * @retval  none
+ */
+void printMsg(CANMsg& msg) {
+    pc.printf("  ID      = 0x%.3x\r\n", msg.id);
+    pc.printf("  Type    = %d\r\n", msg.type);
+    pc.printf("  Format  = %d\r\n", msg.format);
+    pc.printf("  Length  = %d\r\n", msg.len);
+    pc.printf("  Data    =");
+    for(int i = 0; i < msg.len; i++)
+        pc.printf(" 0x%.2X", msg.data[i]);
+    pc.printf("\r\n");
+}
+
+/**
+ * @brief   Main
+ * @note
+ * @param
+ * @retval
+ */
+int main(void)
+{
+#if defined(TARGET_STM32F103C8T6)
+    confSysClock(); //Configure system clock (72MHz HSE clock, 48MHz USB clock)
+#endif
+
+    pc.baud(9600);  // set Serial speed
+    can.frequency(1000000);        // set bit rate to 1Mbps
+    
+#if defined(BOARD1)
+    led = ON;       // turn LED on
+    timer.start();  // start timer
+    pc.printf("CANnucleo_Hello board #1\r\n");
+#else
+    led = OFF;      // turn LED off
+    pc.printf("CANnucleo_Hello board #2\r\n");
+#endif
+
+    while(1) {
+        if(timer.read_ms() >= 1000) {
+
+            // check for timeout
+            timer.stop();   // stop timer
+            timer.reset();  // reset timer
+            counter++;      // increment counter
+            voltage = (analogIn * 3.3f) / 4096.0f;  // read the small drifting voltage from analog input
+            txMsg.clear();      // clear Tx message storage
+            txMsg.id = TX_ID;   // set ID
+            txMsg << counter << voltage;    // append data (total data length must be <= 8 bytes!)
+            if(can.write(txMsg)) {
+
+                // transmit message
+                led = OFF;          // turn LED off
+                pc.printf("-------------------------------------\r\n");
+                pc.printf("CAN message sent\r\n");
+                printMsg(txMsg);
+                pc.printf("  counter = %d\r\n", counter);
+                pc.printf("  voltage = %e V\r\n", voltage);
+            }
+            else
+                pc.printf("Transmission error\r\n");
+        }
+
+        if(can.read(rxMsg)) {
+            led = ON;   // turn LED on
+            pc.printf("-------------------------------------\r\n");
+            pc.printf("CAN message received\r\n");
+            printMsg(rxMsg);
+
+            // Filtering performed by software:
+            if(rxMsg.id == RX_ID) {
+                rxMsg >> counter >> voltage;    // extract data from the received CAN message
+                pc.printf("  counter = %d\r\n", counter);
+                pc.printf("  voltage = %e V\r\n", voltage);
+                timer.start();  // transmission lag
+            }
+        }
+    }
+}