mcp2515: Initial implementation; C; C++

The mcp2515 is a CAN bus controller.  It was developed using the Seeed
CAN bus shield.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/c++/CMakeLists.txt

@@ -327,6 +327,7 @@ add_example (ecezo)
 add_example (mb704x)
 add_example (rf22-server)
 add_example (rf22-client)
+add_example (mcp2515)
 
 # These are special cases where you specify example binary, source file and module(s)
 include_directories (${PROJECT_SOURCE_DIR}/src)
@@ -369,3 +370,4 @@ if (OPENZWAVE_FOUND)
   add_custom_example (tzemt400-example-cxx tzemt400.cxx ozw)
 endif()
 add_custom_example (nmea_gps_i2c_example-cxx nmea_gps_i2c.cxx nmea_gps)
+add_custom_example (mcp2515-txrx-example-cxx mcp2515-txrx.cxx mcp2515)

examples/c++/mcp2515-txrx.cxx

@@ -0,0 +1,125 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <iostream>
+#include <signal.h>
+#include <upm_utilities.h>
+
+#include "mcp2515.hpp"
+
+using namespace std;
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+  if (signo == SIGINT)
+    shouldRun = false;
+}
+
+
+int main(int argc, char **argv)
+{
+    signal(SIGINT, sig_handler);
+
+    // by default we just receive packets
+    bool do_tx = false;
+
+    // if an argument is given, we will transmit packets
+    if (argc > 1)
+        do_tx = true;
+//! [Interesting]
+
+    // NOTE: This example assumes that only two devices are connected
+    // to the CAN bus, and that both devices are running this example;
+    // one in TX (transmit) mode, and one in RX (receive) mode.
+
+    // If this is not the case, then in rx mode you may see other
+    // packets from other devices, or not, depending on whether the
+    // speed is correct for the network.  In tx mode, errors may be
+    // generated on the bus, especially if the CAN bus speed does not
+    // match the rest of the network.
+
+    // You should start the receiver example first.  The transmitter
+    // example will fail after about 5 seconds (timeout) of not being
+    // able to transmit a message.
+
+    // Instantiate a MCP2515 on SPI bus 0 using a hw CS pin (-1).
+    upm::MCP2515 *sensor = new upm::MCP2515(0, 9);
+
+    // By default, after initialization, the baud rate is set to
+    // 50Kbps, and the mode is NORMAL, so we don't need to set any of
+    // that here.
+
+    // our TX payload.  If transmitting, the first number will be
+    // incremented (and rollover) on each transmission.
+    string myPayload = "01234567";
+
+    while (shouldRun)
+    {
+        if (do_tx)
+        {
+            cout << "Loading a packet of 8 numbers (0-7) into a TX buffer..."
+                 << endl;
+            sensor->loadTXBuffer(MCP2515_TX_BUFFER0, 0, false, false,
+                                 myPayload);
+
+            // now lets try to transmit it
+            cout << "Transmitting packet..." << endl;
+            sensor->transmitBuffer(MCP2515_TX_BUFFER0, true);
+
+            myPayload[0]++;
+            cout << "Transmit successful" << endl;
+            cout << endl;
+
+            upm_delay_ms(500);
+        }
+        else
+        {
+            // RX mode
+            // Look for a packet waiting for us in RXB0
+            if (sensor->rxStatusMsgs() == MCP2515_RXMSG_RXB0)
+            {
+                cout << "Packet received in RXB0, decoding..." << endl;
+
+                // now lets retrieve and print it
+                sensor->getRXMsg(MCP2515_RX_BUFFER0);
+
+                sensor->printMsg();
+                cout << endl;
+            }
+
+            upm_delay_ms(100);
+        }
+    }
+
+    cout << "Exiting..." << endl;
+
+    delete sensor;
+//! [Interesting]
+
+    return 0;
+}

examples/c++/mcp2515.cxx

@@ -0,0 +1,79 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <iostream>
+
+#include "mcp2515.hpp"
+
+using namespace std;
+
+int main(int argc, char **argv)
+{
+//! [Interesting]
+
+    // Instantiate a MCP2515 on SPI bus 0 using a hw CS pin (-1).
+    upm::MCP2515 *sensor = new upm::MCP2515(0, -1);
+
+    cout << "Setting loopback mode..." << endl;
+
+    // set the mode to loopback mode.  In loopback mode, transmitted
+    // packets are sent directly to an appropriate receive buffer
+    // without actually going out onto the CAN bus.
+    sensor->setOpmode(MCP2515_OPMODE_LOOPBACK);
+
+    // lets build up a packet and try loading it (8 bytes max).
+    string myPayload = "01234567";
+    cout << "Loading a packet of 8 numbers (0-7) into a TX buffer..." << endl;
+    sensor->loadTXBuffer(MCP2515_TX_BUFFER0, 0, false, false, myPayload);
+
+    // now lets try to transmit it
+    cout << "Transmitting packet..." << endl;
+    sensor->transmitBuffer(MCP2515_TX_BUFFER0, true);
+
+    cout << "Transmit successful" << endl;
+
+    // There should now be a packet waiting for us in RXB0
+    if (sensor->rxStatusMsgs() == MCP2515_RXMSG_RXB0)
+    {
+        cout << "Packet received in RXB0, decoding..." << endl;
+
+        // now lets retrieve and print it
+        sensor->getRXMsg(MCP2515_RX_BUFFER0);
+
+        sensor->printMsg();
+    }
+    else
+    {
+        cout << "No packet found, how strange." << endl;
+    }
+
+    cout << "Exiting..." << endl;
+
+    delete sensor;
+//! [Interesting]
+
+    return 0;
+}