I endend up finding some on eBay, they still come via Chinese Tugboat, but it's better than FOB from Alibaba.
Teensy 3.1 and CAN Bus
- Thread starter BenW
- Start date
I endend up finding some on eBay, they still come via Chinese Tugboat, but it's better than FOB from Alibaba.
There is only one rule and it is very clear - as long as you or anybody else is making ANY profit of it (and I know exactly what's the cost of components to build these boards), you are violating the 'license' under which this design has been made available. You didn't even bother to contact me before offering these for sale so you shouldn't be surprised that I'm not happy about your 'offer'.
You may know how much components cost (though that varies based on vendor and quantity), but that doesn’t include my time and shipping, which isn't even accounted for in my list below, likely another $2 USPS, making my so called profit nil.
CAN Transceiver (1) 2.07
Capacitors (2) 0.52
3.3V Regulator (1) 0.85
Boards (1) 1.75
Soldering at $35/hr - 30min 18
Brk Away Headers 0.25
SD Slot 0.21
Grand Total (no shipping) 23.65
I would like to sincerely apologize for what you thought was me taking advantage, I was just trying to help. As such, I have removed the offer from my previous post.
I agree would be really cool to have it !
gouveiaman
New member
Hi guys
This is my first post in this forum, but i'm being using it for some time, solving my doubts with the help of what you've posted before.
I'm doing a project that involves using 6 Teensy 3.1, and I want to use the CANBus to have communication between them, actually it's more between a Master and 5 Slaves.
Things went quite well, I have the protocol set, and the bus working, when I use one to one communication (2 teensy on the bus).
When I add more teensy 3.1, the canbus doesn't work.
My test setup has a 5V power supply, and every teensy is powered by it, I'm not powering them through the USB port.
I have terminator (120 Ohm), in the start and in the end of the bus, also followed this troubleshooting guide http://www.esd-electronics-usa.com/CAN-Bus-Troubleshooting-Guide.html
Everything is good. The same happens if I only have one terminator resistor.
I noticed that when I have only three teensy 3.1 in the bus, and I disconnect one of them from the bus, the messages sent previously start being sent (in the other two), so I think this is a hardware related problem.
Because I have a few teensy 3.1 with me I've tested with each one of them, and the symptoms are all the same.
Also I wrote this code to test the bus:
Could you help me on this?
I appreciate it.
This is my first post in this forum, but i'm being using it for some time, solving my doubts with the help of what you've posted before.
I'm doing a project that involves using 6 Teensy 3.1, and I want to use the CANBus to have communication between them, actually it's more between a Master and 5 Slaves.
Things went quite well, I have the protocol set, and the bus working, when I use one to one communication (2 teensy on the bus).
When I add more teensy 3.1, the canbus doesn't work.
My test setup has a 5V power supply, and every teensy is powered by it, I'm not powering them through the USB port.
I have terminator (120 Ohm), in the start and in the end of the bus, also followed this troubleshooting guide http://www.esd-electronics-usa.com/CAN-Bus-Troubleshooting-Guide.html
Everything is good. The same happens if I only have one terminator resistor.
I noticed that when I have only three teensy 3.1 in the bus, and I disconnect one of them from the bus, the messages sent previously start being sent (in the other two), so I think this is a hardware related problem.
Because I have a few teensy 3.1 with me I've tested with each one of them, and the symptoms are all the same.
Also I wrote this code to test the bus:
Code:
#include <FlexCAN.h>
int ledPin = 13;
FlexCAN CANbus(250000);
static CAN_message_t rxmsg, txmsg;
String msg;
bool pinState;
// -------------------------------------------------------------
void setup(void)
{
Serial.begin(38400);
CANbus.begin();
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, 1);
delay(1000);
Serial.println(F("Hello Teensy 3.1 CAN Test."));
}
// -------------------------------------------------------------
void loop(void)
{
String Smsg;
while (!CANbus.available()){
toggle(ledPin);
delay(25);
}
if (CANbus.read(rxmsg) )
printCanMsg(rxmsg);
delay(1000);
toggle(ledPin);
}
void toggle(int pinNum) {
// set the LED pin using the pinState variable:
digitalWrite(pinNum, pinState);
// if pinState = 0, set it to 1, and vice versa:
pinState = !pinState;
}
void printCanMsg(CAN_message_t m){
String a = "";
for (int i=0; i<m.len ; i++)
a += (char)m.buf[i];
Serial.println(a);
}
void serialEvent(){
char inChar;
while (Serial.available()){
inChar = (char)Serial.read();
switch (inChar){
case 'a':
sendmsg1();
break;
case 'b':
sendmsg2();
break;
default :
sendmsg();
}
}
}
void sendmsg(){
String a="abcdefgh";
txmsg.id=0x0001;
txmsg.len=8;
for (int i=0; i< txmsg.len; i++)
txmsg.buf[i]=a[i];
CANbus.write(txmsg);
}
void sendmsg1(){
String a="12345678";
txmsg.id=0x0001;
txmsg.len=8;
for (int i=0; i< txmsg.len; i++)
txmsg.buf[i]=a[i];
CANbus.write(txmsg);
}
void sendmsg2(){
String a="A1B2C3D4";
txmsg.id=0x0001;
txmsg.len=8;
for (int i=0; i< txmsg.len; i++)
txmsg.buf[i]=a[i];
CANbus.write(txmsg);
}Could you help me on this?
I appreciate it.
Last edited:
Otmar
New member
CAN bus requires an interface chip that you seem to be lacking in your picture. It's basically an open collector bus. Your tx pins are not expecting to be tied together and that may damage the chips.
Maybe check out this project to help you on your way.
https://oshpark.com/shared_projects/VeJFD9qA
It may be possible to simulate it with resistors and diodes for a board level application like your demo, but I haven't really considered it before.
gouveiaman
New member
Thanks for pointing me to the correct place.
Basically I need a Can Transceiver, to each one of them so I can have a bus.
I'm new to Can Bus, so I didn't expected that, and was thinking that Teensy 3.1 was an out of the box solution to have a Can Bus network, but basically one only get a way to connect to an existing bus, but not to make one.
I've tried to understand how to do it using resistors and diodes as you said, but couldn't understand how, can you point me on something?
Thanks again for the info.
gouveiaman
New member
Thank you for this.
It works like a charm, used a 1N4148 Diode and a 2,2k resitor for the pullup to 3,3V, and it just works with the bonus of using only one wire instead of two. Also I tested it with a wire of about 5 meters (the pdf refers less than 1 meter), with a speed of 500000.
I want to put another question related to the library and the Flexcan controller on the chip.
The library only accepts 8 possible filters, but could the chip accept more than 8?
In the reference manual (in first page of this thread) there is this:
when we look at the code in kinetics.h:
Code:
/* Rx FIFO ID Filter Table Element 0 to 127 */
#define FLEXCAN0_IDFLT_TAB0 (*(vuint32_t*)(FLEXCAN0_BASE+0xE0))
#define FLEXCAN0_IDFLT_TAB(n) (*(vuint32_t*)(FLEXCAN0_BASE+0xE0+(n*4)))
//#define FLEXCAN0_IDFLT_TAB(n) (*(vuint32_t*)(FLEXCAN0_BASE+0xE0+(n<<2)))and in the Flexcan.c:
Code:
void FlexCAN::setFilter(const CAN_filter_t &filter, uint8_t n)
{
if ( 8 > n ) {
if (filter.ext) {
FLEXCAN0_IDFLT_TAB(n) = ((filter.rtr?1:0) << 31) | ((filter.ext?1:0) << 30) | ((filter.id & FLEXCAN_MB_ID_EXT_MASK) << 1);
} else {
FLEXCAN0_IDFLT_TAB(n) = ((filter.rtr?1:0) << 31) | ((filter.ext?1:0) << 30) | (FLEXCAN_MB_ID_IDSTD(filter.id) << 1);
}
}
}this is limited to 8 filters, but could we change it to use more? 128 Possible filters?
i've used this one for the teensy and it works fine, you should be able to find even lower than 5bucks.
http://www.aliexpress.com/store/pro...tion-module-of-CAN-bus/345545_1357782272.html
http://www.aliexpress.com/store/pro...tion-module-of-CAN-bus/345545_1357782272.html
Copyright doesn't apply to hardware, so no license is being violated.
Copyright can pertain to the design of a car, a painting, or a circuit board layout. It doesn't matter whether its software/hardware.
Noone was copying anyways, the debate was in regards to resale of the item, which should not be part of this topic and dealt with personally.
(mods feel free to delete this post)
Noone was copying anyways, the debate was in regards to resale of the item, which should not be part of this topic and dealt with personally.
(mods feel free to delete this post)
Do you have the correct byte packet to reset Oil/Desmo Service for the Panigale ?
Just in case anyone else wanted to be able to detect the presence of the RTR bit being set in a received packet, the add an rtr element to the CAN_message type in the FlexCAN.h as shown:
then in the FlexCAN.cpp file, add the RTR line to the read(message) code as shown:
To write the RTR bit, the CAN write function needs to have another mask set on it in the presence of an RTR bit. This is a modification of the last part of the write(message) code in the FlexCAN.cpp:
Again, this is probably bad coding (im more a hardware guy), but it works. Im sure there are much more elegant ways to do this.
Cheers
Code:
typedef struct CAN_message_t {
uint32_t id; // can identifier
uint8_t ext; // identifier is extended
uint8_t rtr; // RTR bit
uint8_t len; // length of data
uint16_t timeout; // milliseconds, zero will disable waiting
uint8_t buf[8];
} CAN_message_t;then in the FlexCAN.cpp file, add the RTR line to the read(message) code as shown:
Code:
// get identifier and dlc
msg.len = FLEXCAN_get_length(FLEXCAN0_MBn_CS(rxb));
msg.ext = (FLEXCAN0_MBn_CS(rxb) & FLEXCAN_MB_CS_IDE)? 1:0;
msg.rtr = (FLEXCAN0_MBn_CS(rxb) & FLEXCAN_MB_CS_RTR)? 1:0;
msg.id = (FLEXCAN0_MBn_ID(rxb) & FLEXCAN_MB_ID_EXT_MASK);To write the RTR bit, the CAN write function needs to have another mask set on it in the presence of an RTR bit. This is a modification of the last part of the write(message) code in the FlexCAN.cpp:
Code:
if(msg.ext) {
if(msg.rtr) {
FLEXCAN0_MBn_CS(buffer) = FLEXCAN_MB_CS_CODE(FLEXCAN_MB_CODE_TX_ONCE)
| FLEXCAN_MB_CS_LENGTH(msg.len) | FLEXCAN_MB_CS_SRR | FLEXCAN_MB_CS_IDE | FLEXCAN_MB_CS_RTR;
} else {
FLEXCAN0_MBn_CS(buffer) = FLEXCAN_MB_CS_CODE(FLEXCAN_MB_CODE_TX_ONCE)
| FLEXCAN_MB_CS_LENGTH(msg.len) | FLEXCAN_MB_CS_SRR | FLEXCAN_MB_CS_IDE;
}
} else {
if(msg.rtr){
FLEXCAN0_MBn_CS(buffer) = FLEXCAN_MB_CS_CODE(FLEXCAN_MB_CODE_TX_ONCE)
| FLEXCAN_MB_CS_LENGTH(msg.len)| FLEXCAN_MB_CS_RTR;
} else {
FLEXCAN0_MBn_CS(buffer) = FLEXCAN_MB_CS_CODE(FLEXCAN_MB_CODE_TX_ONCE)
| FLEXCAN_MB_CS_LENGTH(msg.len);
}
}Again, this is probably bad coding (im more a hardware guy), but it works. Im sure there are much more elegant ways to do this.
Cheers
Last edited:
EagleUp + Maxwell renderer
Teensy MCP2551
Hi. I'm new on the CAN protocol , I'm developing a project in wich I need to use a Can bus, but I'm having some issues with it. I'm using the Teensy 3.1 and the MCP2551 transcriver. I made some Teensy programs to write and read, i have two Teensys and two MCPs but I dont know why does not work, I think that my conecctions are ok but i think that i don't understand quite well the "Masks Filters and ID's stuff" can someone help me? I will really apreciate it.
This is the code of the frist Teensy
And this is the second Code
I'm having some issues with the IDs, Idont know if i have to define a ID for the frist teensy or how do i know what id to use?
Hi. I'm new on the CAN protocol , I'm developing a project in wich I need to use a Can bus, but I'm having some issues with it. I'm using the Teensy 3.1 and the MCP2551 transcriver. I made some Teensy programs to write and read, i have two Teensys and two MCPs but I dont know why does not work, I think that my conecctions are ok but i think that i don't understand quite well the "Masks Filters and ID's stuff" can someone help me? I will really apreciate it.
This is the code of the frist Teensy
Code:
#include <FlexCAN.h>
#include <kinetis_flexcan.h>
const int baudRate = 50000;
const int ledPin = 13;
const int delayTime = 1000;
int count = 0;
FlexCAN myCAN(baudRate);
CAN_message_t message;
CAN_message_t rxmsg;
void setup(){
pinMode(ledPin,OUTPUT);
Serial.begin(9600);
digitalWrite(ledPin,HIGH);
myCAN.begin();
Serial.println("CAN PROTOCOL - INIT ... WAIT...");
digitalWrite(ledPin,LOW);
delay(5000);
digitalWrite(ledPin,HIGH);
Serial.println("Master ON - READY");
}
void loop(){
Serial.print("MY CAN data: ");
//Serial.println(myCAN.available());
if(myCAN.available()){
myCAN.read(rxmsg);
Serial.println(rxmsg.buf[0]);
if(rxmsg.buf[0] == 49){
Serial.println("Message Sent");
message.buf[0] = count;
message.buf[1] = count + 1;
message.len = 2 ;
message.id = 0x2;
myCAN.write(message);
count++;
}
}
//Serial.print("Data buf[0]: ");
//Serial.println(rxmsg.buf[0]);
delay(delayTime);
}And this is the second Code
Code:
#include <FlexCAN.h>
#include <kinetis_flexcan.h>
const int baudRate = 50000;
const int ledPin = 13;
const int delayTime = 50;
FlexCAN myCAN(baudRate);
CAN_message_t message;
CAN_message_t rxmsg;
void setup(){
pinMode(ledPin,OUTPUT);
Serial.begin(9600);
myCAN.begin();
Serial.println("CAN PROTOCOL - INIT ... WAIT...");
digitalWrite(ledPin,LOW);
delay(5000);
digitalWrite(ledPin,HIGH);
Serial.println("SLAVE ON - READY");
}
void loop(){
for(int i = 1 ; i < 50 ; i++){
message.buf[0] = i;
message.id = 0x1;
myCAN.write(message);
Serial.print("Message: ");
Serial.println(message.buf[0]);
digitalWrite(ledPin,HIGH);
delay(delayTime);
digitalWrite(ledPin,LOW);
delay(delayTime);
}
if (myCAN.available()){
Serial.println("Message Recived");
myCAN.read(rxmsg);
Serial.println(rxmsg.buf[0]);
Serial.println(rxmsg.buf[1]);
}
}I'm having some issues with the IDs, Idont know if i have to define a ID for the frist teensy or how do i know what id to use?
Check the comments in the FlexCAN.cpp to see whether you have the library version that does support 50000 baudrate. The latest version on github does, the official release 1.0 doesn't.
You are right, what i mean was 500000 bauds. I already modify it but still dont work
any ideas?Here is my wiring
Last edited:
You are not setting the message length when sending from the second Teensy, so (buf[0] == 49) will always be false.