Mega328 AU + MCP2515 pcb issue

Projects General Guidance
1

my second attempt on atmega328p-au based pcb (first one had some issues that @LarryD & @johnwasser pointed out and following their points and advice i made changes to my "v2" pcb)
** Still my PCB designing skill is below zero and im learning

This board does communicate with arduino ide and i can upload sketches, do analog/digital in/out with no issues at all so far however to get close to what my aim is in this board i added MCP2515 and TJA1050T chip so i could get CANBUS data as well.

As mentioned above atmega328 and usb comms work really well but no matter what i cannot get the canbus to work (not able to send or receive anything on canbus)
I tried @autow autowp's library as well as
@coryjfowler 's library GitHub - coryjfowler/MCP_CAN_lib: MCP_CAN Library but reached nowhere.

(using same libraries, arduino uno and a chinese made mpc2515 board i can read and send CAN data but not on my pcb)

So i thought i would post my schematic and pcb here and maybe someone can see an obvious error that i made and can help me pinpoint and fix my issue.

Schematic
Schematic850×1152 63.6 KB

PCB
PCB1020×779 128 KB

2

Post moved because it was in the wrong place. You put it in the section for getting the IDE working.

1 Like
3

You don't seem to have the MCP2515 "INT" pin connected. Does the library you use need the INT signal?

4

My arduino uno & chinese mcp2515 board works with autowp library with no issues and INT pin is not connected

5

AREF and AVCC are not usually connected together as AREF cannot then be switched in software.

If changed, 100nF on AREF is needed.

A GND pour on top of PCBs is no longer recommended.

6

noted. will do that and remove GND pour on next pcb.

can these have effect on the mcp2515/tja1050 combination not to receive any canbus data ?

7

Running autowp's library CAN_Receive example sketch:
while serial monitor running if i touch mcp2515 chip (specifically around pin 12-15) i get some gibberish reading in serial monitor

20:05:41.907 -> ------- CAN Read ----------
20:05:41.907 -> ID  DLC   DATA
20:05:43.077 -> 40000407 0 
20:05:43.145 -> 7FF 0 
20:05:43.215 -> 704 0 
20:05:43.249 -> 6 0 
20:05:43.284 -> 0 0 
20:05:43.353 -> 0 0 
20:05:43.353 -> 0 0 
20:05:43.421 -> 0 0 
20:05:43.455 -> 8 0 
20:05:43.455 -> 0 0 
20:05:43.455 -> 0 0 
20:05:43.489 -> DFFF003F 1 3F 
20:05:43.489 -> 0 0 
20:05:43.489 -> 0 0 
20:05:43.523 -> 0 0 
20:05:43.523 -> 0 0 
20:05:43.523 -> 0 0 
20:05:43.557 -> 0 1 FF 
20:05:43.557 -> 0 0 
20:05:43.557 -> 400007F8 0 
20:05:43.592 -> 8 0 
20:05:43.592 -> DFE01F1F 3 7F FF 3F 
20:05:43.592 -> 0 0 
20:05:43.592 -> 7F8 0 
20:05:43.661 -> 404 0 
20:05:43.901 -> 784 0 
20:05:43.901 -> 7C4 0 
20:05:43.970 -> 4 0 
20:05:44.108 -> 406 0 
20:05:44.177 -> 7E7 0 
20:05:44.246 -> 4 0 
20:05:44.280 -> 9C1FF880 0 
20:05:44.280 -> 404 0 
20:05:44.314 -> 901C8080 0 
20:05:44.349 -> 404 0 
20:05:44.383 -> 9C1C8080 0 
20:05:44.383 -> 981CC0F0 0 
20:05:44.418 -> 9FDFFFC0 0 
20:05:44.452 -> 407 0 
20:05:44.487 -> 407 0 
20:05:44.521 -> 404 0 
20:05:44.521 -> 901CFFFE 0 
20:05:44.556 -> 4 0 
20:05:44.556 -> 400 0 
20:05:44.659 -> 0 0 
20:05:44.693 -> 7FE 0 
20:05:44.762 -> 7FC 0 
20:05:44.796 -> 404 0 
20:05:44.865 -> 9FFFFFFF 0 
20:05:44.967 -> 0 0 
20:05:45.001 -> 0 0 
20:05:45.035 -> 0 0 
20:05:45.035 -> 0 0 
20:05:45.035 -> 0 0 
20:05:45.069 -> 83E3070F 7 0 0 0 0 0 0 0 
20:05:45.069 -> 0 0 
20:05:45.069 -> C0E73F03 0 
20:05:45.104 -> 78 0 
20:05:45.104 -> 0 0 
20:05:45.104 -> 0 0 
20:05:45.104 -> 18 0 
20:05:45.139 -> 0 0 
20:05:45.139 -> CFEF3F7F 7 F 0 7 0 0 0 0 
20:05:45.139 -> 0 0 
20:05:45.173 -> 0 0 
20:05:45.173 -> 40000000 0 
20:05:45.173 -> DFFFFFFF 8 7F 7F 3F 0 FF 2 0 0 
20:05:45.207 -> 80040000 0 
20:05:45.207 -> 0 0 
20:05:45.207 -> 0 0 
20:05:45.242 -> DFE0073F 7 FF 3 3F 1C 0 0 0 
20:05:45.242 -> 0 0 
20:05:45.242 -> 40000078 0 
20:05:45.242 -> C7EF3F7F 0 
20:05:45.277 -> 1E0 0 
20:05:45.277 -> DFFF7FFF 7 FF 7F F 0 FF 20 0 
20:05:45.277 -> F8 0 
20:05:45.277 -> 9FFF0000 0 
20:05:45.277 -> 400007F8 0 
20:05:45.311 -> 0 0 
20:05:45.311 -> 6 0 
20:05:45.345 -> 706 0 
20:05:45.345 -> 4 0 
20:05:45.414 -> 7FF 8 0 0 0 0 0 0 0 0 
20:05:45.551 -> 604 0 
20:05:45.551 -> 9FFCF8F8 0 
20:05:46.958 -> DFFFFFFF 0 
20:05:46.958 -> DFFFF8F0 0 
20:05:46.992 -> DFFFFFFF 8 FF FF FF FF FF F0 FF FF 
20:05:47.095 -> 40000038 3 0 7 F 
20:05:47.095 -> 0 0 
20:05:47.130 -> 8 1 3 
20:05:47.130 -> 40000008 0 
20:05:47.130 -> 0 7 0 3 0 7 3 F 7 
20:05:47.130 -> 38 3 0 1 0 
20:05:47.130 -> 0 1 0 
20:05:47.164 -> 40000018 3 F F 3 
20:05:47.164 -> 0 0 
20:05:47.164 -> 0 7 7 1 F 7 3 0 7 
20:05:47.199 -> C0630703 3 F 1F F 
20:05:47.199 -> 0 0 
20:05:47.233 -> 9C1F8080 8 0 0 0 0 0 0 0 0 
20:05:47.233 -> 407 8 0 0 0 0 0 0 0 0
8

No.

9

Tried many libraries, tried another pcb without gnd pour but still not able to receive any CAN messages...

Can anyone help me with this ?

10

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