ADVES
example showing how to use the mbed CAN API
Diff: main.cpp
- Revision:
- 1:6f8ffb2c2dd7
- Parent:
- 0:1b9561cd1c36
- Child:
- 2:6546e4a2d593
--- a/main.cpp Fri Mar 17 16:38:46 2017 +0000
+++ b/main.cpp Sat Mar 18 18:37:21 2017 +0000
@@ -1,34 +1,26 @@
/*
- * A demo showing how to use CAN bus and the CANMsg library's << (append) and the >> (extract) operators
+ * An example showing how to use the mbed CAN API:
*
* Two affordable (less than $3 on ebay) STM32F103C8T6 boards (20kB SRAM, 64kB Flash),
+ * (see [https://developer.mbed.org/users/hudakz/code/STM32F103C8T6_Hello/] for more details)
* 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.
+ *
+ * For more details see the wiki page <https://developer.mbed.org/users/hudakz/code/CAN_Hello/>
*
- * 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 23
*
- * NOTE: If you'd like to use an STM32F103C8T6 board uncomment line 28
- *
- * The same code is used for both NUCLEO boards, but:
+ * The same code is used for both mbed boards, but:
* For board #1 compile the example without any change.
- * For board #2 comment out line 27 before compilation
+ * For board #2 comment out line 23 before compiling
*
* 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!
+#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"
@@ -47,12 +39,11 @@
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
+Serial pc(PA_2, PA_3);
+CAN can(PA_11, PA_12); // CAN Rx pin name, CAN Tx pin name
CANMsg rxMsg;
CANMsg txMsg;
DigitalOut led(LED_PIN);
@@ -64,10 +55,10 @@
/**
* @brief Prints CAN msg to PC's serial terminal
* @note}
- * @param CANMess to print
+ * @param CANMessage to print
* @retval none
*/
-void printMsg(CANMsg& msg) {
+void printMsg(CANMessage& 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);
@@ -87,36 +78,29 @@
int main(void)
{
#if defined(TARGET_STM32F103C8T6)
- confSysClock(); //Configure system clock (72MHz HSE clock, 48MHz USB clock)
+ 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
-
+ 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");
+ led = ON; // turn the LED on
+ timer.start(); // start timer
+ pc.printf("CAN_Hello board #1\r\n");
#else
led = OFF; // turn LED off
- pc.printf("CANnucleo_Hello board #2\r\n");
+ pc.printf("CAN_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
+ 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 the LED off
pc.printf("-------------------------------------\r\n");
pc.printf("CAN message sent\r\n");
printMsg(txMsg);
@@ -128,7 +112,7 @@
}
if(can.read(rxMsg)) {
- led = ON; // turn LED on
+ led = ON; // turn the LED on
pc.printf("-------------------------------------\r\n");
pc.printf("CAN message received\r\n");
printMsg(rxMsg);
@@ -138,7 +122,7 @@
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
+ timer.start(); // transmission lag
}
}
}