B4R Question CAN bus for ESP32 by rCAN

[peacemaker]

HI, All

I'm tired trying to make CAN bus by ESP8266...
Two ESP32 modules are received at last, and trying again

It looks like the ready lib for ESP32 is https://www.b4x.com/android/forum/threads/rcan-library.120832/.
Question about pinout, circuit diagram and the lib initialization:

can.Initialize("can_DataAvailable", 53, 0, can.SPEED_500KBPS)

What ESP32 pins better to use (not occupied during boot) for CAN bus and what are their number for init ?

Lib's example code is with 53 and 0, but ... what is 53 pin ?

If to look at this pinout, and choose, say, GPIO16 (receiving from MCP2515 TX pin) and GPIO17 (transmitting to MCP2515 RX pin) - init should be like:

can.Initialize("can_DataAvailable", 16, 17, can.SPEED_500KBPS)

?

 

[peacemaker]

Solved.
If to solder so: GPIO17 to RX of the CAN-adapter, GPIO16 to TX of the CAN-adapter
PCA82C250



and initialize so:

can.Initialize("can_DataAvailable", 17, 16, can.SPEED_100KBPS)

sending and receivig by CAN bus works !

Spoiler: sketch

#Region Project Attributes
    #AutoFlushLogs: True
    #CheckArrayBounds: True
    #StackBufferSize: 300
#End Region

Sub Process_Globals
    Public Serial1 As Serial
    Private can As CAN
    Private tim As Timer
    'Private pin As Pin
    Private JustStarted As Boolean = True
    #if Sender
    Public MyAddr As Int = 1
    #else
    Public MyAddr As Int = 2
    #End If
    Public Count As Long
    Public bc As ByteConverter
End Sub

Private Sub AppStart
    Serial1.Initialize(256000)
    Log(CRLF, "AppStart....wait for 3 sec")
    Delay(3000)
    Log(can.Initialize("can_DataAvailable", 17, 16, can.SPEED_100KBPS))
   
    #if Sender
    tim.Initialize("tim_Tick",1000)
    tim.Enabled=True
    #end if
End Sub

Sub can_DataAvailable(Data() As Byte)
    Log("I (", MyAddr, ") received from ID: ", can.MessageId, ": ", Data)
End Sub

Sub tim_Tick
    If JustStarted Then
        Dim m() As Byte = "Start"
        can.SendMessageExtended(MyAddr, m)
        JustStarted=False
    Else
        Dim d() As Byte = bc.StringToBytes(Count)
        Log("Sending from ", MyAddr, ": ", d)
        can.SendMessage(MyAddr, d)
        Count = Count + 1
    End If
End Sub

 

[peacemaker]

And it seems to me that it works due to the MCU has built-in CAN-controller, and externally just CAN-transceiver IC (with UART-port) is needed.
But MCP25215 IC is such CAN-controller with SPI-port that is on the board together with second IC - the CAN-transceiver TJA1050 IC (with UART-port).

And it looks like that this fact is the reason why ESP8266 cannot work with CAN-bus simply.

 

[janderkan]

3 times correct

 

[tigrot]

For pins http://www.iotsharing.com/2017/09/how-to-use-arduino-esp32-can-interface.html?m=1

 

[peacemaker]

Here the main question that what pins\functions are provided by B4R libraries, and setup all for this