Allow pure virtual bus

code/headers/can.hpp

@@ -588,5 +588,17 @@ namespace r2d2::can_bus {
 
             return tick != can_timeout;
         }
+
+        /**
+         * Guess whether we are connected to the outside world,
+         * by checking if we are in the Error Passive Mode. When
+         * no physical cable is attached, the error mode will activate.
+         *
+         * This will also return true on a high/abnormal rate of errors on the bus.
+         * @return
+         */
+        static bool has_physical_connection() {
+            return (port<Bus>->CAN_SR >> 18) & 1;
+        }
     };
 }

code/headers/channel.hpp

@@ -126,7 +126,19 @@ namespace r2d2::can_bus {
             }
 
             // Wait for space, space is created in the interrupt
-            while (!space_in_tx_queue);
+            while (!space_in_tx_queue) {
+                // ERRP = Error Passive Mode
+                bool errp = (port<Bus>->CAN_SR >> 18) & 1;
+
+                // Are we in error mode?
+                if (errp) {
+                    // We are in error mode, so we'll want to update the tx_queue
+                    // with more recent information. In the event that we are connected
+                    // again (e.g. this is a temporary problem), we'll send recent information.
+                    tx_queue.pop();
+                    break;
+                }
+            }
 
             tx_queue.push(frame);
         }
@@ -188,7 +200,7 @@ namespace r2d2::can_bus {
             if (length <= 8) {
                 detail::_can_frame_s frame{};
 
-                for(size_t i = 0; i < length; i++){
+                for (size_t i = 0; i < length; i++) {
                     frame.data.bytes[i] = data[i];
                 }
 
@@ -205,7 +217,7 @@ namespace r2d2::can_bus {
                     detail::_can_frame_s frame{};
 
                     // Has to be 8 bytes; frame.length is copied in a lower layer
-                    for(uint_fast8_t j = 0; j < 8; j++){
+                    for (uint_fast8_t j = 0; j < 8; j++) {
                         frame.data.bytes[j] = data[j + i];
                     }
 
@@ -221,7 +233,7 @@ namespace r2d2::can_bus {
                 if (remainder > 0) {
                     detail::_can_frame_s frame{};
 
-                    for(uint_fast8_t i = 0; i < remainder; i++){
+                    for (uint_fast8_t i = 0; i < remainder; i++) {
                         frame.data.bytes[i] = data[i + total];
                     }
 
@@ -282,7 +294,7 @@ namespace r2d2::can_bus {
             frame.type = static_cast<frame_type>(can_frame.frame_type);
             frame.request = can_frame.mode == detail::_can_frame_mode::READ;
 
-            for(uint_fast8_t i = 0; i < 8; i++){
+            for (uint_fast8_t i = 0; i < 8; i++) {
                 frame.bytes[i] = can_frame.data.bytes[i];
             }
 

code/main.cpp

@@ -8,48 +8,23 @@ int main() {
     // kill the watchdog
     WDT->WDT_MR = WDT_MR_WDDIS;
 
-    hwlib::wait_ms(10);
+    hwlib::wait_ms(1000);
 
     r2d2::comm_c comm;
+    r2d2::comm_c comm2;
 
-    std::array<frame_id, 8> frames = {
-        r2d2::frame_type::BUTTON_STATE
-    };
+    comm2.listen_for_frames({r2d2::frame_type::BUTTON_STATE});
 
-    comm.listen_for_frames(frames);
+    for (;;) {
+        frame_button_state_s state;
+        state.pressed = true;
 
-    auto led = hwlib::target::pin_out(hwlib::target::pins::d6);
+        comm.send(state);
 
-    uint32_t start = hwlib::now_us();
-    uint32_t counter = 0;
-    uint32_t ticks = 0;
+        while (comm2.has_data()) {
+            const auto frame = comm2.get_data();
 
-    for (;;) {
-        comm.request(frame_type::BUTTON_STATE);
-
-        while (comm.has_data()) {
-            auto frame = comm.get_data();
-
-            // This module doesn't handle requests
-            if (frame.request) {
-                continue;
-            }
-
-            if (frame.type != frame_type::BUTTON_STATE) {
-                continue;
-            }
-
-            counter += 1;
-            const auto pressed = frame.as_frame_type<frame_type::BUTTON_STATE>().pressed;
-            led.write(pressed);
-
-            ticks = hwlib::now_us() - start;
-            if (ticks >= 1'000'000) {
-                hwlib::cout << counter << "\r\n";
-                start = hwlib::now_us();
-                ticks = 0;
-                counter = 0;
-            }   
+            hwlib::cout << "rec fr\n";
         }
     }
 }