feat(library): Serial Transmitter Interface

examples/platformio/serial_transmitter_prototype.cpp

@@ -0,0 +1,255 @@
+#if __has_include("Arduino.h")
+#include "Arduino.h"
+#define ARDUINO_IS_INCLUDED 1
+#else
+#define ARDUINO_IS_INCLUDED 0
+#endif
+
+/* Packet rate enumeration. */
+typedef enum packet_rate_index_e
+{
+    PACKET_RATE_4HZ,
+    PACKET_RATE_25HZ,
+    PACKET_RATE_50HZ,
+    PACKET_RATE_100HZ,
+    PACKET_RATE_150HZ,
+    PACKET_RATE_200HZ,
+    PACKET_RATE_250HZ,
+    PACKET_RATE_333HZ,
+    PACKET_RATE_500HZ,
+    PACKET_RATE_1000HZ,
+    PACKET_RATE_COUNT
+} packet_rate_index_t;
+
+/* Selected packet rate. */
+const packet_rate_index_t selected_packet_rate = PACKET_RATE_50HZ;
+uint32_t *packet_rate_us = nullptr;
+
+/* Time structure for the packet rate. */
+typedef struct software_realtime_counter_s
+{
+    uint32_t time_us = 0;
+    uint32_t time_us_last = 0;
+    uint32_t time_us_delta = 0;
+    int32_t time_us_error = 0;
+    const int32_t time_us_max_allowed_error = 2;
+} software_realtime_counter_t;
+
+/* Packed 11-bit RC Channels. */
+struct rc_channels_packed_s
+{
+    uint16_t ch1 : 11;
+    uint16_t ch2 : 11;
+    uint16_t ch3 : 11;
+    uint16_t ch4 : 11;
+    uint16_t ch5 : 11;
+    uint16_t ch6 : 11;
+    uint16_t ch7 : 11;
+    uint16_t ch8 : 11;
+    uint16_t ch9 : 11;
+    uint16_t ch10 : 11;
+    uint16_t ch11 : 11;
+    uint16_t ch12 : 11;
+    uint16_t ch13 : 11;
+    uint16_t ch14 : 11;
+    uint16_t ch15 : 11;
+    uint16_t ch16 : 11;
+} __attribute__((packed));
+
+typedef struct rc_channels_packed_s rc_channels_packed_t;
+
+/* CRSF Frame structure and union. */
+typedef struct crsf_frame_s
+{
+    uint8_t sync;
+    uint8_t length;
+    uint8_t type;
+    uint8_t payload[60];
+    uint8_t crc;
+} crsf_frame_t;
+
+const size_t crsf_frame_size = sizeof(crsf_frame_t);
+
+typedef union crsf_tx_frame_u
+{
+    crsf_frame_t frame;
+    uint8_t buffer[crsf_frame_size];
+} crsf_tx_frame_t;
+
+/* Time structure instance. */
+software_realtime_counter_t *sw_timer = nullptr;
+
+crsf_tx_frame_t crsf_tx_frame;
+
+/* CRC8-DVB-S2. */
+uint8_t crc8_dvb_s2(uint8_t crc, const uint8_t data)
+{
+    crc ^= data;
+    for (uint8_t i = 0; i < 8; i++)
+    {
+        if (crc & 0x80)
+        {
+            crc = (crc << 1) ^ 0xD5;
+        }
+        else
+        {
+            crc <<= 1;
+        }
+    }
+    return crc;
+}
+
+/* This function calculates the CRC for the CRSF frame
+from the type to the end of the payload. */
+uint8_t calculate_crc(const crsf_tx_frame_t *crsf_tx_frame)
+{
+    uint8_t crc = 0;
+    crc = crc8_dvb_s2(crc, crsf_tx_frame->frame.type);
+    for (uint8_t i = 0; i < crsf_tx_frame->frame.length - 2; i++)
+    {
+        crc = crc8_dvb_s2(crc, crsf_tx_frame->frame.payload[i]);
+    }
+    return crc;
+}
+
+/* Exit handlers. */
+void exit_success_handler()
+{
+    /* Clean up and stop. */
+    delete[] packet_rate_us;
+    delete sw_timer;
+
+    /* Print a message to the serial monitor. */
+    Serial.println("Program has ended successfully.");
+}
+
+void exit_time_max_allowed_error_handler()
+{
+    /* Print a message to the serial monitor. */
+    Serial.print("Program has ended with an error: ");
+    Serial.println("Time error is greater than the maximum allowed error.");
+
+    /* Print how far the sw_timer error is from the packet rate in microseconds. */
+    Serial.print("Time Error: ");
+    Serial.print(sw_timer->time_us_error);
+    Serial.println(" us");
+
+    /* Clean up and stop. */
+    delete[] packet_rate_us;
+    delete sw_timer;
+}
+
+#if ARDUINO_IS_INCLUDED == 1
+void setup()
+{
+    Serial.begin(115200);
+    while (!Serial)
+    {
+        delay(10);
+    }
+
+    /* Dynamically allocate memory for the packet rate,
+    and calculate the sw_timer in microseconds for each packet rate. */
+    packet_rate_us = new uint32_t[PACKET_RATE_COUNT];
+    packet_rate_us[PACKET_RATE_4HZ] = (1000000UL / 4UL);
+    packet_rate_us[PACKET_RATE_25HZ] = (1000000UL / 25UL);
+    packet_rate_us[PACKET_RATE_50HZ] = (1000000UL / 50UL);
+    packet_rate_us[PACKET_RATE_100HZ] = (1000000UL / 100UL);
+    packet_rate_us[PACKET_RATE_150HZ] = (1000000UL / 150UL);
+    packet_rate_us[PACKET_RATE_200HZ] = (1000000UL / 200UL);
+    packet_rate_us[PACKET_RATE_250HZ] = (1000000UL / 250UL);
+    packet_rate_us[PACKET_RATE_333HZ] = (1000000UL / 333UL);
+    packet_rate_us[PACKET_RATE_500HZ] = (1000000UL / 500UL);
+    packet_rate_us[PACKET_RATE_1000HZ] = (1000000UL / 1000UL);
+
+    /* Initialize the sw_timer structure. */
+    sw_timer = new software_realtime_counter_t;
+
+    /* Initialise Serial1 with 1.87M baud rate. */
+    Serial1.begin(1875000);
+    memset(&crsf_tx_frame, 0, crsf_frame_size);
+
+    /* Initialise the RC Channels structure. */
+    rc_channels_packed_t rc_channels_packed;
+    rc_channels_packed.ch1 = 992;
+    rc_channels_packed.ch2 = 992;
+    rc_channels_packed.ch3 = 992;
+    rc_channels_packed.ch4 = 992;
+    rc_channels_packed.ch5 = 178;
+    rc_channels_packed.ch6 = 992;
+    rc_channels_packed.ch7 = 992;
+    rc_channels_packed.ch8 = 992;
+    rc_channels_packed.ch9 = 992;
+    rc_channels_packed.ch10 = 992;
+    rc_channels_packed.ch11 = 992;
+    rc_channels_packed.ch12 = 992;
+    rc_channels_packed.ch13 = 992;
+    rc_channels_packed.ch14 = 992;
+    rc_channels_packed.ch15 = 992;
+    rc_channels_packed.ch16 = 992;
+
+    /* Prepare the CRSF RC Channels Packed frame. */
+    crsf_tx_frame.frame.sync = 0xC8; // NB: EdgeTX uses 0xEE which is incorrect.
+    crsf_tx_frame.frame.length = 24;
+    crsf_tx_frame.frame.type = 0x16;
+    memcpy(crsf_tx_frame.frame.payload, &rc_channels_packed, sizeof(rc_channels_packed));
+    crsf_tx_frame.frame.crc = calculate_crc(&crsf_tx_frame);
+
+    /* Print a message to the serial monitor. */
+    Serial.println("Testing CRSF Serial Transmitter Prototype...");
+
+    /* Initialise Serial1 with 1.87M baud rate. */
+    Serial1.begin(1875000);
+    memset(&crsf_tx_frame, 0, crsf_frame_size);
+
+    /* Set the time in microseconds. */
+    sw_timer->time_us = micros();
+    sw_timer->time_us_last = sw_timer->time_us;
+}
+
+void loop()
+{
+
+    static uint32_t iteration = 0;
+
+    /* Calculate the number of iterations based on the selected packet rate and the equivalent total execution time of three seconds. */
+    static const uint32_t iterations = (3000000UL / packet_rate_us[selected_packet_rate]);
+
+    if (iteration < iterations)
+    {
+        /* Calculate the time delta in microseconds. */
+        sw_timer->time_us = micros();
+        sw_timer->time_us_delta = sw_timer->time_us - sw_timer->time_us_last;
+
+        /* Calculate the time error in microseconds. */
+        sw_timer->time_us_error = sw_timer->time_us - (sw_timer->time_us_last + packet_rate_us[selected_packet_rate]);
+
+        /* If the time delta is greater than or equal to the packet rate in microseconds and the time error is less than the maximum allowed error. */
+        if (sw_timer->time_us_delta >= packet_rate_us[selected_packet_rate] && sw_timer->time_us_error < sw_timer->time_us_max_allowed_error)
+        {
+            /* Set the last time in microseconds. */
+            sw_timer->time_us_last = sw_timer->time_us;
+
+            /* Write 64 bytes to Serial1. */
+            Serial1.write(crsf_tx_frame.buffer, crsf_tx_frame.frame.length + 1);
+
+            /* Increment the iteration. */
+            iteration++;
+        }
+
+        /* If the time error is greater than or equal to the maximum allowed error. */
+        else if (sw_timer->time_us_error >= sw_timer->time_us_max_allowed_error)
+        {
+            /* Exit the program. */
+            atexit(exit_time_max_allowed_error_handler);
+            exit(EXIT_FAILURE);
+        }
+    }
+    else
+    {
+        /* Exit the program. */
+        atexit(exit_success_handler);
+        exit(EXIT_SUCCESS);
+    }
+}
+#endif

library.json

@@ -1,7 +1,7 @@
 {
     "$schema": "https://raw.githubusercontent.com/platformio/platformio-core/develop/platformio/assets/schema/library.json",
     "name": "CRSFforArduino",
-    "version": "1.1.0-1.0.0",
+    "version": "1.1.0-2024.9.3",
     "description": "An Arduino Library for communicating with ExpressLRS and TBS Crossfire receivers.",
     "keywords": "arduino, remote-control, arduino-library, protocols, rc, radio-control, crsf, expresslrs",
     "repository":

library.properties

@@ -1,5 +1,5 @@
 name=CRSFforArduino
-version=1.1.0-1.0.0
+version=1.1.0-2024.9.3
 author=Cassandra Robinson <nicad.heli.flier@gmail.com>
 maintainer=Cassandra Robinson <nicad.heli.flier@gmail.com>
 sentence=CRSF for Arduino brings the Crossfire Protocol to the Arduino ecosystem.

platformio.ini

@@ -13,7 +13,7 @@ core_dir = .pio/core
 default_envs =
     ; defect_detector
     development
-    ; ${build.all}
+    ; ${build.commonly_used}
 extra_configs =
     targets/common.ini
     targets/quality_control.ini
@@ -31,9 +31,41 @@ test_dir =
 
 [env:development]
 board = adafruit_metro_m4
+build_flags =
+build_src_flags =
+    ; Force GNU C++ 23:
+    -std=gnu++23
+    ; Compile hardening flags:
+    -O2
+    -Wall
+    -Wextra
+    -Wformat
+    -Wformat=2
+    ; -Wconversion ; Disabled due to spamming conversion issues in packages outside the scope of CRSF for Arduino.
+    -Wimplicit-fallthrough
+    -U_FORTIFY_SOURCE
+    -D_FORTIFY_SOURCE=3
+    -D_GLIBCXX_ASSERTIONS
+    ; -fsrict-flex-arrays=3 ; Not available in GCC Arm Compiler v12.3.1
+    -fstack-clash-protection
+    -fstack-protector-strong
 build_src_filter = 
-    +<../examples/platformio/main.cpp>
+    +<../examples/platformio/serial_transmitter_prototype.cpp>
     +<*/*/*.cpp>
     +<*.cpp>
 build_type = debug
+build_unflags =
+    -c++11
+    -Os
+check_flags =
+    --enable=all
+    --disable=missingInclude
+    --disable=unusedFunction
+    --language=c++
+    --std=c++23
+check_severity = low, medium, high
+check_skip_packages = yes
+check_tool = cppcheck
 extends = env_common_samd51
+platform_packages =
+    platformio/toolchain-gccarmnoneeabi @ 1.120301.0 ; PlatformIO's latest GCC Compiler version

src/CFA_Config.hpp

@@ -46,11 +46,11 @@ See https://semver.org/ for more information. */
 // These are the pre-release version details which are only used if CRSFFORARDUINO_VERSION_IS_PRERELEASE is set to 1.
 // NOTE: Pre-release versions are not recommended for production use.
 #if CRSFFORARDUINO_VERSION_IS_PRERELEASE == 1
-#define CRSFFORARDUINO_VERSION_PRE   "1.0.0"
-#define CRSFFORARDUINO_VERSION_BUILD_DATE "2024-7-21"
-#define CRSFFORARDUINO_VERSION_BUILD_MAJOR 1
-#define CRSFFORARDUINO_VERSION_BUILD_MINOR 0
-#define CRSFFORARDUINO_VERSION_BUILD_PATCH 0
+#define CRSFFORARDUINO_VERSION_PRE   "2024.9.3"
+#define CRSFFORARDUINO_VERSION_BUILD_DATE "2024-9-3"
+#define CRSFFORARDUINO_VERSION_BUILD_YEAR 2024
+#define CRSFFORARDUINO_VERSION_BUILD_MONTH 9
+#define CRSFFORARDUINO_VERSION_BUILD_DAY 3
 #endif
 
 /* Failsafe Options

src/SerialReceiver/CRSF/CRSF.hpp

@@ -24,7 +24,7 @@
 
 #pragma once
 
-#include "../CRC/CRC.hpp"
+#include "../common/CRC/CRC.hpp"
 #include "CRSFProtocol.hpp"
 
 namespace serialReceiverLayer

src/SerialReceiver/SerialReceiver.cpp

@@ -233,12 +233,22 @@ namespace serialReceiverLayer
         CRSF_DEBUG_SERIAL_PORT.println();
         CRSF_DEBUG_SERIAL_PORT.flush();
 
+#if CRSF_DEBUG_ENABLE_VERSION_OUTPUT > 0
         CRSF_DEBUG_SERIAL_PORT.print("Version: ");
+#if CRSF_VERSION_IS_PRERELEASE > 0
+        CRSF_DEBUG_SERIAL_PORT.print(CRSFFORARDUINO_VERSION);
+        CRSF_DEBUG_SERIAL_PORT.print("-");
+        CRSF_DEBUG_SERIAL_PORT.println(CRSFFORARDUINO_VERSION_PRERELEASE);
+        CRSF_DEBUG_SERIAL_PORT.print("Build date: ");
+        CRSF_DEBUG_SERIAL_PORT.println(CRSFFORARDUINO_VERSION_BUILD_DATE);
+#else
         CRSF_DEBUG_SERIAL_PORT.println(CRSFFORARDUINO_VERSION);
         CRSF_DEBUG_SERIAL_PORT.print("Build date: ");
         CRSF_DEBUG_SERIAL_PORT.println(CRSFFORARDUINO_VERSION_DATE);
+#endif
         CRSF_DEBUG_SERIAL_PORT.println();
         CRSF_DEBUG_SERIAL_PORT.flush();
+#endif
 
         for (int i = 0; i < 93; i++)
         {

src/SerialReceiver/Telemetry/Telemetry.hpp

@@ -26,7 +26,7 @@
 
 #include "Arduino.h"
 
-#include "../CRC/CRC.hpp"
+#include "../common/CRC/CRC.hpp"
 #include "../CRSF/CRSFProtocol.hpp"
 #include "../SerialBuffer/SerialBuffer.hpp"