QT Chan
Using CAN bus with (not just NUCLEO) mbed boards support Cortex-M0
Revision 0:1b9561cd1c36, committed 2017-03-17
- Comitter:
- hudakz
- Date:
- Fri Mar 17 16:38:46 2017 +0000
- Child:
- 1:6f8ffb2c2dd7
- Commit message:
- Initial release.
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/CANMsg.lib Fri Mar 17 16:38:46 2017 +0000 @@ -0,0 +1,1 @@ +https://developer.mbed.org/users/hudakz/code/CANMsg/#3d11ed680b6a
--- /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
+ }
+ }
+ }
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-STM32F103C8T6.lib Fri Mar 17 16:38:46 2017 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/hudakz/code/mbed-STM32F103C8T6/#09d8c2eacb4d
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Fri Mar 17 16:38:46 2017 +0000 @@ -0,0 +1,1 @@ +https://mbed.org/users/mbed_official/code/mbed/builds/093f2bd7b9eb \ No newline at end of file