Thanks timolappalainen to help me. But this doesn't work.
This is what i did in the first time:
I downloaded NMEA2000_mcp-master; NMEA2000-master; CAN_BUS_Shield-master-2
I test "DataDisplay2" but i don't work. They are "CAN device failed to open Running...CAN device failed to open all the time"
After:
I test "receive_check.ino" in CAN_BUS_Shield-master-2. I change "Slave select" of SPI (const int SPI_CS_PIN = 9;) because in my seeed CAN shield (v1-2) the CS (SS) is in 10. After I changed (const int SPI_CS_PIN =10) he tell me "CAN BUS Shield init ok!" but nothing else.
After:
I return in "DataDisplay2.ino" i connect the pin10 in pin9 (I twisted the pin and i connected a wire between pin 10 to 9 because i don't know where i can change the instruction in your software) but he tells me all time the same message (CAN device failed to open Running...CAN device failed)
In the same time i changed #define N2k_CAN_INT_PIN 21 to 2 (because I tested electronically "INT" of my MCP2515 is connected to the pin 2 of arduino MEGA2560)
There are also library specific defines:
mcp_can:
#define N2k_SPI_CS_PIN 53 // Pin for SPI Can Select
#define N2k_CAN_INT_PIN 21 // Use interrupt and it is connected to pin 21
#define USE_MCP_CAN_CLOCK_SET 8 // possible values 8 for 8Mhz and 16 for 16 Mhz clock
You should not touch any library code at all. If test example, you can take copy of it and modify that. If you need to change definition, you do it in your code before including NMEA2000_CAN.h - not modifying itself. Like this:
When you see message "CAN device ready Running ... ", it means that Mega communicates with MCP2515 and CS must be right. You can easily test by changing CS definition to e.g. 9 and you should see "CAN device failed..."
The problem is so after MCP2515. It can be on int pin definition or chrystal definition. Example should work without interrupt, when you do not have too much traffic. So you can comment int pin definition until you get some data out.
Since you have seeed studio version it uses default 16MHz chrystal. Some other manufacturers shields uses 8 MHz chrystal and requires definition for that.
On the bus side there are two possible problems. Mixing CANH/CANL and missing termination resistors. With standard colours CANH is white and CANL is blue wire. And on bus it is best to have exactly 2 termination resistors. This means that if you measure with ohm meter between CANH/CANL, you should see 60 ohm resistance. If not, you have to add resistors to both end of the longest bus. In test table with short cable (<2 m) I have time to time only one resistor and it still works. So if you are doing table test with DST800 and Mega, close P1 on shield.
I just tested with my old Mega test board and DST800 with example DataDisplay2. The shield is my hand made, but similar as Seeeds shield except pins.
Works fine with or without interrupt. When powered, starts showing
In Main Handler: 128259
Boat speed: SOW:0.00, SOG:not available, Paddle wheel
...
1-
When I test the program "DataDisplay2" with the code:
N2k_SPI_CS_PIN 9 (he says "CAN device failed to open")
When I test the program "DataDisplay2" with the code:
N2k_SPI_CS_PIN 10 (he says "CAN device ready, Running ...")
So I'm sure CS is on the pin 10.
2-
Quartz is a 16Mhz I'm sure.
3-
I commented "N2k_CAN_INT_PIN 2" (because on my card it's the 2) because I only have one sensor on my bus (the DST800)
4-
CAN_H is the white
CAN_L is blue
It was good for me.
I forgot to mension resistance, since it too obvious for me and basics of building NMEA 2000 system.
On NMEA 2000 bus you need to have one 120 ohm resistor on both longest end. This means that if you measure resistance between CANH and CANL, you should see 60 ohm resistance. NOTE! It is ohm not kilo ohm! Any drop cable on the bus should not exceed 6 m. The total length depends of used cable. For commonly used cable the maximum length is 100 m.
The 120 ohm termination resistors are just standard resistors. You do not need to buy any expensive brand resistors. Also you have one on shield, if you close P1.
Hi all.
In this thread back in 2017 I found some decision about controlling a Raymarine autopilot over NMEA2000. There was some ideas but not tested yet - etc.
Is there somebody there have made an Arduino board to remote control a autopilot over NMEA2000 ?
Is it possible to send Roll of the boat without sending Heading? If not and there are two devices sending Heading how does one select which Heading to use/read in third one?
Heading is on PGN 127250 and roll PGN 127257. So simply do not send heading message.
It is also possible to leave data out from message, which has multiple fields by defining it as NA. Then if there is e.g. two different devices sending engine data with PGN 127489, one can do
If there are really two devices sending heading, there should be way on receiver side to select, which one to use. Some MDF:s has that some does not. if you are making your own device, you should use my N2kDeviceList module and lock the device you want to follow to device "NAME" not source address, since that may change due to address claiming.
PGN 127257 contains Yaw which is commented as Heading in radians. I will test today if the display will display it too as heading. Should be able to select correct data to be shown based on device name if PGN 127257 heading is also shown as heading . Also should be able to select heading for the third device by sending and reading PGN 127250.
Sorry that my question not linked with this great NMEA library, but it is experienced NMEA-community so I will try...
I make own stm32 project.
Does anybody has experience with correct PGN 127497 generation? to be displayed on MFDs.
We produce 2 PGNs: 127497 and 127489, they both longer than 2 bytes and must be sent in separate packets.
We do it in the same procedure for both, but results are different:
Checked by Actisence reader software:
PGN 127489 is displayed correctly, assembled from 2 packets
PGN 127497 is displayed as 2 separate messages, first one contains correct information (but named as 8-byte message, though it has 9 bytes)
but second one totally not correct, belong to another engine instance and ruin the information on the display when we connect real device under this instance.
May be somebody has an example of raw CAN bus log with successful PGN 127497 sending and receiving.
The PGN127497 is fast packet and not listed on library fp messages, so it can not receive it right. I can add this in coming days.
If you need it immediately, other option is that you add it to known list with tNMEA2000 class function ExtendFastPacketMessages and create handlers by yourself. You can then switch handlers, when I have added it. Please do not add handlers to library modules, so your own handlers will not be deleted on library update.
We didn't use your great library for Arduino, we made it from scratch on our STM-controller (already had J1939 implemented before).
PGN 127489 is fast packet message too and decoded right by Actisense. So it is confusing for us why same algorythm for 127489 and 127497 provides different results when connected to real devices (Actisense, MFD).
Will try your library too (have arduino Duo) and compare, thanks!
I could not find the multimedia class 125 and functions (130&140) so I guess it is not implemented. Could that be interesting as there is so less device supporting the nmea2k?
Thought about building a media central controllable by the MFD.
There is no multimedia PGN functions on the library. On N2kMessages module are the most common PGNs. It is pretty simple to create new module e.g. N2kMultimedia.h/.cpp and write functions as in N2kMessages.