фикс перекоса каналов на ардупилоте

air/main.cpp

@@ -1,4 +1,5 @@
 #include <sys/ioctl.h>
+#include <sys/poll.h>
 #include <asm/termbits.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
@@ -11,17 +12,26 @@
 #include <cstring>
 #include <atomic>
 #include <span>
+#include <sys/time.h>
 
+/**
+ * Вспомогательная функция для получения текущего времени в миллисекундах
+ */
+inline int64_t milliseconds() {
+    timeval tv{};
+    gettimeofday(&tv,nullptr);
+    return ((tv.tv_sec * 1000000l) + tv.tv_usec) / 1000;
+}
 
-
+constexpr int64_t SBUS_SEND_FRAME_INTERVAL = 15;
+constexpr int64_t SBUS_RXLOSS_INTERVAL = 500;
 
 class UDPServer {
-private:
+public:
     int sockfd;
     sockaddr_in server_addr, client_addr;
     socklen_t client_len;
 
-public:
     UDPServer(uint16_t port) : client_len(sizeof(client_addr)) {
         // Создание UDP сокета
         sockfd = socket(AF_INET, SOCK_DGRAM, 0);
@@ -84,9 +94,9 @@ struct SbusData {
     bool lost_frame = false;
     bool failsafe = false;
     bool ch17 = false, ch18 = false;
-    static constexpr size_t NUM_CH = 16;
+    static constexpr size_t NUM_CH = 18;
-    static constexpr int16_t SBUS_CH_MIN = 173;
+    static constexpr int16_t SBUS_CH_MIN = 173 + 20;
-    static constexpr int16_t SBUS_CH_MAX = 1812;
+    static constexpr int16_t SBUS_CH_MAX = 1812 - 20;
     int16_t ch[NUM_CH];
 
     /* Message len */
@@ -100,52 +110,68 @@ struct SbusData {
     static constexpr uint8_t CH18_MASK_ = 0x02;
     static constexpr uint8_t LOST_FRAME_MASK_ = 0x04;
     static constexpr uint8_t FAILSAFE_MASK_ = 0x08;
-    /* Data */
+    uint8_t binaryBuffer[25];
-    uint8_t buf_[BUF_LEN_];
+
+    typedef struct sbusChannels_s {
+        // 176 bits of data (11 bits per channel * 16 channels) = 22 bytes.
+        unsigned int chan0 : 11;
+        unsigned int chan1 : 11;
+        unsigned int chan2 : 11;
+        unsigned int chan3 : 11;
+        unsigned int chan4 : 11;
+        unsigned int chan5 : 11;
+        unsigned int chan6 : 11;
+        unsigned int chan7 : 11;
+        unsigned int chan8 : 11;
+        unsigned int chan9 : 11;
+        unsigned int chan10 : 11;
+        unsigned int chan11 : 11;
+        unsigned int chan12 : 11;
+        unsigned int chan13 : 11;
+        unsigned int chan14 : 11;
+        unsigned int chan15 : 11;
+    } __attribute__((__packed__)) sbusChannels_t;
+    static_assert(sizeof(sbusChannels_s) == 22);
+    struct sbusFrame_s {
+        uint8_t syncByte = HEADER_;
+        sbusChannels_t channels{};
+        uint8_t flags{};
+        /**
+         * The endByte is 0x00 on FrSky and some futaba RX's, on Some SBUS2 RX's the value indicates the telemetry byte that is sent after every 4th sbus frame.
+         *
+         * See https://github.com/cleanflight/cleanflight/issues/590#issuecomment-101027349
+         * and
+         * https://github.com/cleanflight/cleanflight/issues/590#issuecomment-101706023
+         */
+        uint8_t endByte = FOOTER_;
+    } __attribute__ ((__packed__));
+    static_assert(sizeof(sbusFrame_s) == sizeof(binaryBuffer));
 
     void fillDataBuf() {
-        /* Assemble packet */
+        auto* dest = reinterpret_cast<sbusFrame_s*>(binaryBuffer);
-        buf_[0] = HEADER_;
+        dest->syncByte = HEADER_;
-        buf_[1] = static_cast<uint8_t>((ch[0] & 0x07FF));
+        dest->channels.chan0 = std::min(std::max(ch[0], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[2] = static_cast<uint8_t>((ch[0] & 0x07FF) >> 8 |
+        dest->channels.chan1 = std::min(std::max(ch[1], SBUS_CH_MIN), SBUS_CH_MAX);
-                (ch[1] & 0x07FF) << 3);
+        dest->channels.chan2 = std::min(std::max(ch[2], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[3] = static_cast<uint8_t>((ch[1] & 0x07FF) >> 5 |
+        dest->channels.chan3 = std::min(std::max(ch[3], SBUS_CH_MIN), SBUS_CH_MAX);
-                (ch[2] & 0x07FF) << 6);
+        dest->channels.chan4 = std::min(std::max(ch[4], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[4] = static_cast<uint8_t>((ch[2] & 0x07FF) >> 2);
+        dest->channels.chan5 = std::min(std::max(ch[5], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[5] = static_cast<uint8_t>((ch[2] & 0x07FF) >> 10 |
+        dest->channels.chan6 = std::min(std::max(ch[6], SBUS_CH_MIN), SBUS_CH_MAX);
-                (ch[3] & 0x07FF) << 1);
+        dest->channels.chan7 = std::min(std::max(ch[7], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[6] = static_cast<uint8_t>((ch[3] & 0x07FF) >> 7 |
+        dest->channels.chan8 = std::min(std::max(ch[8], SBUS_CH_MIN), SBUS_CH_MAX);
-                (ch[4] & 0x07FF) << 4);
+        dest->channels.chan9 = std::min(std::max(ch[9], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[7] = static_cast<uint8_t>((ch[4] & 0x07FF) >> 4 |
+        dest->channels.chan10 = std::min(std::max(ch[10], SBUS_CH_MIN), SBUS_CH_MAX);
-                (ch[5] & 0x07FF) << 7);
+        dest->channels.chan11 = std::min(std::max(ch[11], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[8] = static_cast<uint8_t>((ch[5] & 0x07FF) >> 1);
+        dest->channels.chan12 = std::min(std::max(ch[12], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[9] = static_cast<uint8_t>((ch[5] & 0x07FF) >> 9  |
+        dest->channels.chan13 = std::min(std::max(ch[13], SBUS_CH_MIN), SBUS_CH_MAX);
-                (ch[6] & 0x07FF) << 2);
+        dest->channels.chan14 = std::min(std::max(ch[14], SBUS_CH_MIN), SBUS_CH_MAX);
-        buf_[10] = static_cast<uint8_t>((ch[6] & 0x07FF) >> 6  |
+        dest->channels.chan15 = std::min(std::max(ch[15], SBUS_CH_MIN), SBUS_CH_MAX);
-                 (ch[7] & 0x07FF) << 5);
+
-        buf_[11] = static_cast<uint8_t>((ch[7] & 0x07FF) >> 3);
+        dest->flags = 0;
-        buf_[12] = static_cast<uint8_t>((ch[8] & 0x07FF));
+        if (ch[16] >= (SBUS_CH_MAX + SBUS_CH_MAX) / 2) { dest->flags |= CH17_MASK_; }
-        buf_[13] = static_cast<uint8_t>((ch[8] & 0x07FF) >> 8 |
+        if (ch[17] >= (SBUS_CH_MAX + SBUS_CH_MAX) / 2) { dest->flags |= CH18_MASK_; }
-                 (ch[9]  & 0x07FF) << 3);
+
-        buf_[14] = static_cast<uint8_t>((ch[9] & 0x07FF) >> 5 |
+        dest->endByte = FOOTER_;
-                 (ch[10] & 0x07FF) << 6);
-        buf_[15] = static_cast<uint8_t>((ch[10] & 0x07FF) >> 2);
-        buf_[16] = static_cast<uint8_t>((ch[10] & 0x07FF) >> 10 |
-                 (ch[11] & 0x07FF) << 1);
-        buf_[17] = static_cast<uint8_t>((ch[11] & 0x07FF) >> 7  |
-                 (ch[12] & 0x07FF) << 4);
-        buf_[18] = static_cast<uint8_t>((ch[12] & 0x07FF) >> 4  |
-                 (ch[13] & 0x07FF) << 7);
-        buf_[19] = static_cast<uint8_t>((ch[13] & 0x07FF) >> 1);
-        buf_[20] = static_cast<uint8_t>((ch[13] & 0x07FF) >> 9  |
-                 (ch[14] & 0x07FF) << 2);
-        buf_[21] = static_cast<uint8_t>((ch[14] & 0x07FF) >> 6  |
-                 (ch[15] & 0x07FF) << 5);
-        buf_[22] = static_cast<uint8_t>((ch[15] & 0x07FF) >> 3);
-        buf_[23] = 0x00 | (ch17 * CH17_MASK_) | (ch18 * CH18_MASK_) |
-                 (failsafe * FAILSAFE_MASK_) |
-                 (lost_frame * LOST_FRAME_MASK_);
-        buf_[24] = FOOTER_;
     }
 
 };
@@ -208,6 +234,15 @@ public:
         return fd;
     }
 
+    int drain() {
+        int ret;
+        do {
+            ret = ioctl(fd, TCSBRK, 1);
+        } while (ret < 0 && errno == EINTR);
+
+        return ret;
+    }
+
     // Метод для записи данных в порт
     bool write(std::span<const uint8_t> data) {
         if (fd < 0) return false;
@@ -219,7 +254,10 @@ public:
         }
 
         // Принудительная отправка данных
-        // tcdrain(fd);
+        if (drain() < 0) {
+            std::cerr << "Failed to flush data to serial port" << std::endl;
+            return false;
+        }
         return true;
     }
 };
@@ -245,17 +283,26 @@ int main(int argc, char* argv[]) {
         std::cout << "Press Ctrl+C to exit" << std::endl;
 
         SbusData sb{};
+        int64_t lastSbusWrite = 0;
+        int64_t lastSbusRecv = 0;
 
-        int packet_count = 0;
+        int packetCount = 0;
+        int totalPacketCount = 0;
+        int64_t lastStatisticsShow = milliseconds();
         while (true) {
+            pollfd udpFd{.fd = udp_server.sockfd, .events = POLLIN, .revents = 0};
+            poll(&udpFd, 1, SBUS_SEND_FRAME_INTERVAL / 4);
+
+            if (udpFd.revents & POLLIN) {
                 // Прием UDP пакета
                 std::vector<uint16_t> data = udp_server.receive();
+                lastSbusRecv = milliseconds();
 
                 if (!data.empty()) {
-                packet_count++;
+                    packetCount++;
 
-                for (int i = 0; i < data.size() && i < SbusData::NUM_CH; ++i) {
+                    for (int i = 0; i < SbusData::NUM_CH; ++i) {
-                    auto item = static_cast<double>(data[i]);
+                        auto item = i < data.size() ? static_cast<double>(data[i]) : 1500.0;
                         item -= 1000.0;
                         item = std::min(item, 1000.0);
                         item = std::max(item, 0.0);
@@ -270,15 +317,23 @@ int main(int argc, char* argv[]) {
                         }
                     }
                     sb.fillDataBuf();
-                if (!serial.write(sb.buf_)) {
+                }
-                    break;
             }
 
-                // Выводим статистику каждые 100 пакетов
+            const auto now = milliseconds();
-                if (packet_count % 100 == 0) {
+            if (now - lastSbusWrite >= SBUS_SEND_FRAME_INTERVAL && now - lastSbusRecv <= SBUS_RXLOSS_INTERVAL) {
-                    std::cout << "Received " << packet_count << " packets total" << std::endl;
+                lastSbusWrite = now;
+                if (!serial.write(sb.binaryBuffer)) {
+                    break;
                 }
             }
+
+            if (now - lastStatisticsShow >= 1000) {
+                lastStatisticsShow = now;
+                totalPacketCount += packetCount;
+                std::cout << "Received " << totalPacketCount << " packets total, " << packetCount << " in last second" << std::endl;
+                packetCount = 0;
+            }
         }
 
     } catch (const std::exception& e) {