I've run into a case of 'In theory it works, but in reality'....
I'm using the CAN-BUS Shield V1.2 from Seeed studio. Many things are written in broken english, so I'm starting to wonder if I can trust all of the information. http://wiki.seeed.cc/CAN-BUS_Shield_V1.2/
The USB Host Shield is a discontinued official Arduino model. https://www.arduino.cc/en/Main/ArduinoUSBHostShield
(I would link to the libraries, but I am unable to post more than 2 links)
CAN-BUS Pins:
AREF
ICSP (SCK, MISO, MOSI)
P9 - CS (SS)
P2 - INT
NC
IOREF
RST
3.3V
5V
Vin
USB Host Pins:
ICSP (SCK, MISO, MOSI)
P10 - SS
P7 - GPX
P8 - INT (actually RES?)
P9 - RES (actually INT?)
The only conflict I see is Pin 9 (CS on CAN, RES on USB). This is where it gets hazy... While the documentation on the bottom of the USBHost page implies that Pin 9 is RES, in the code Pin 9 is actually INT.
So, assuming Pin 9 is actually INT, I re-routed it to Pin 45 on on the Mega and changed it in the UsbCore.h file:
//typedef MAX3421e<P10, P9> MAX3421E; // old
typedef MAX3421e<P10, P45> MAX3421E; // new
Here is a snippet of the code I am running:
#include <PS3BT.h>
#include <usbhub.h>
#ifdef dobogusinclude
#include <spi4teensy3.h>
#include <SPI.h>
#endif
#include <Bounce2.h>
#include <Time.h>
#include <TimeLib.h>
#include <SPI.h>
#include "mcp_can.h"
const int SPI_CS_PIN = 9;
MCP_CAN CAN(SPI_CS_PIN); // Set CS pin
void setup()
{
Serial.begin(115200);
// THIS WORKS
if (Usb.Init() == -1) {
Serial.print(F("\r\nOSC did not start"));
}
Serial.print(F("\r\nPS3 Bluetooth Library Started"));
// THIS FAILS
while (CAN_OK != CAN.begin(CAN_500KBPS))
{
Serial.println("CAN BUS Shield init fail");
Serial.println(" Init CAN BUS Shield again");
delay(100);
}
Serial.println("CAN BUS Shield init ok!");
}
The CAN-BUS Fails to init until I physically remove the USB Host Shield.
If I remove the CAN-BUS code, The USB Host Shield functions normally.
If I remove the USB Host code, the CAN-BUS Shield still DOES NOT init.
I tried to sift through the CAN-BUS init code a little, and I can only assume it's failing to communicate via SPI. What am I missing here?
