mg_bt/CMakeLists.txt

@@ -37,6 +37,7 @@ set(SOURCES
 
 
 add_executable(mg_bt_executor ${SOURCES})
+add_executable(mg_i2cnode i2cmodule/i2cnode.cpp)
 
 target_include_directories(
   mg_bt_executor
@@ -45,10 +46,14 @@ target_include_directories(
   include
 )
 
+target_link_libraries(mg_i2cnode i2c)
+
 ament_target_dependencies(mg_bt_executor ${PACKAGE_DEPS})
+ament_target_dependencies(mg_i2cnode rclcpp mg_msgs)
 
 install( TARGETS
   mg_bt_executor
+  mg_i2cnode
   DESTINATION lib/${PROJECT_NAME}
 )
 

mg_bt/i2cmodule/i2cnode.cpp

@@ -0,0 +1,47 @@
+#include "rclcpp/rclcpp.hpp"
+#include "mg_msgs/srv/i2c.hpp"
+
+extern "C" {
+
+#include <fcntl.h>
+#include <linux/i2c-dev.h>
+#include <sys/ioctl.h>
+#include <i2c/smbus.h>
+}
+class MgI2c : public rclcpp::Node {
+    using I2cSrv = mg_msgs::srv::I2c;
+
+  public:
+    MgI2c(const std::string& name) : rclcpp::Node(name), i2c_fd_(open("/dev/i2c-1", O_RDWR)) { // NOLINT
+        auto cb
+          = [this](I2cSrv::Request::ConstSharedPtr req, I2cSrv::Response::SharedPtr resp) { send_req(req, resp); };
+        i2c_srv_ = create_service<I2cSrv>("/i2c", cb);
+    }
+
+    void send_req(I2cSrv::Request::ConstSharedPtr req, I2cSrv::Response::SharedPtr resp) const {
+        ioctl(i2c_fd_, I2C_SLAVE, req->addr); // NOLINT
+        i2c_smbus_write_byte(i2c_fd_, req->data);
+        int ch = 0;
+
+        rclcpp::Rate rate(100);
+
+        while (ch == 0 || (ch < 256 && ch > 0)) {
+            ch = i2c_smbus_read_byte(i2c_fd_);
+            rate.sleep();
+        }
+        resp->resp.push_back(ch);
+        RCLCPP_INFO(get_logger(), "Recieved %d", resp->resp.front());
+    }
+
+  private:
+    rclcpp::Service<mg_msgs::srv::I2c>::SharedPtr i2c_srv_;
+    int                                           i2c_fd_;
+};
+
+int main(int argc, const char* const* argv) {
+    rclcpp::init(argc, argv);
+    rclcpp::spin(std::make_shared<MgI2c>("i2cu"));
+    rclcpp::shutdown();
+
+    return 0;
+}

mg_bt/package.xml

@@ -14,6 +14,7 @@
   <depend>behaviortree_ros2</depend>
   <depend>btcpp_ros2_interfaces</depend>
   <depend>mg_msgs</depend>
+  <depend>libi2c-dev</depend>
 
   <test_depend>ament_lint_auto</test_depend>
   <test_depend>ament_lint_common</test_depend>

mg_bt/src/mg_tree_executor.cpp

@@ -2,6 +2,7 @@
 
 #include "behaviortree_cpp/xml_parsing.h"
 #include "tree_nodes/calib.hpp"
+#include "tree_nodes/i2c.hpp"
 #include "tree_nodes/move_point.hpp"
 #include "tree_nodes/rotate.hpp"
 #include "tree_nodes/zero.hpp"
@@ -26,6 +27,7 @@ namespace mg {
         factory.registerNodeType<mg::MovePointNode>("MovePoint", node());
         factory.registerNodeType<mg::RotateNode>("RotateNode", node());
         factory.registerNodeType<mg::ZeroNode>("ZeroNode", node());
+        factory.registerNodeType<mg::I2cNode>("I2CSignal", node());
         factory.registerNodeType<mg::CalibWidthNode>("CalibWidth", node(), [this]() { return this->position(); });
     }
 

mg_bt/src/tree_nodes/i2c.hpp

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "behaviortree_ros2/bt_service_node.hpp"
+#include "mg_msgs/srv/i2c.hpp"
+
+namespace mg {
+    class I2cNode : public BT::RosServiceNode<mg_msgs::srv::I2c> {
+      public:
+        I2cNode(const std::string& name, const BT::NodeConfig& conf, const BT::RosNodeParams& params) :
+          BT::RosServiceNode<mg_msgs::srv::I2c>(name, conf, params) { }
+
+        static BT::PortsList providedPorts() {
+            return providedBasicPorts({ BT::InputPort<int>("Address", 42, {}),
+                                        BT::InputPort<int>("Data", 0, {}),
+                                        BT::OutputPort<int>("Result") });
+        }
+
+        bool setRequest(typename Request::SharedPtr& req) override {
+            req->addr = getInput<int>("Address").value_or(42);
+            req->data = getInput<int>("Result").value_or(0);
+            return true;
+        }
+
+        BT::NodeStatus onResponseReceived(const typename Response::SharedPtr& resp) override {
+            setOutput<int>("Result", resp->resp.front());
+            return BT::NodeStatus::SUCCESS;
+        }
+    };
+}

mg_msgs/CMakeLists.txt

@@ -19,6 +19,7 @@ rosidl_generate_interfaces(${PROJECT_NAME}
   "action/Rotate.action"
   "srv/CalcPath.srv"
   "srv/SendDouble.srv"
+  "srv/I2c.srv"
 )
 
 ament_package()

mg_msgs/srv/I2c.srv

@@ -0,0 +1,4 @@
+uint8 addr
+uint8 data
+---
+uint8[] resp