Flightsim/fs/flight sim

.gitignore

@@ -3,3 +3,5 @@
 
 .vscode
 build
+
+.DS_Store

SPI_Slave_Driver/SpiTransport.cpp

@@ -0,0 +1,62 @@
+#include "SpiTransport.hpp"
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_REGISTER(spi_transport, LOG_LEVEL_INF);
+
+#define SPI_SLAVE_NODE DT_NODELABEL(spi1)
+
+SpiTransport::SpiTransport() : 
+    spi_dev(DEVICE_DT_GET(SPI_SLAVE_NODE)),
+    handshake_gpio(GPIO_DT_SPEC_GET(SPI_SLAVE_NODE, handshake_gpios)) {
+
+    // SPI Mode 0, 8-bit, Slave Mode
+    spi_cfg.operation = SPI_WORD_SET(8) | SPI_OP_MODE_SLAVE;
+    spi_cfg.frequency = 0; // External clock from Pi
+    spi_cfg.slave = 0;
+}
+
+int SpiTransport::init() {
+    if (!device_is_ready(spi_dev)) {
+        LOG_ERR("SPI Slave device not ready");
+        return -ENODEV;
+    }
+
+    if (!gpio_is_ready_dt(&handshake_gpio)) {
+        LOG_ERR("Handshake GPIO not ready");
+        return -ENODEV;
+    }
+
+    gpio_pin_configure_dt(&handshake_gpio, GPIO_OUTPUT_INACTIVE);
+    return 0;
+}
+
+void SpiTransport::swap_buffers() {
+    processed_idx = active_idx;
+    active_idx = (active_idx == 0) ? 1 : 0;
+}
+
+int SpiTransport::transfer_sync() {
+    struct spi_buf rx_buf = {
+        .buf = buffers[active_idx],
+        .len = PACKET_SIZE
+    };
+    const struct spi_buf_set rx_bufs = { .buffers = &rx_buf, .count = 1 };
+
+    // Signal Pi: "I am ready and listening"
+    gpio_pin_set_dt(&handshake_gpio, 1);
+
+    // This blocks until the Pi drives the clock for exactly PACKET_SIZE bytes
+    // and the NSS pin is toggled.
+    int ret = spi_read(spi_dev, &spi_cfg, &rx_bufs);
+
+    // Signal Pi: "I am busy/processing"
+    gpio_pin_set_dt(&handshake_gpio, 0);
+
+    if (ret == 0) {
+        swap_buffers();
+    } else {
+        LOG_ERR("SPI Transfer failed: %d", ret);
+    }
+
+    return ret;
+}

SPI_Slave_Driver/SpiTransport.hpp

@@ -0,0 +1,38 @@
+#ifndef SPI_TRANSPORT_HPP
+#define SPI_TRANSPORT_HPP
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/spi.h>
+#include <zephyr/drivers/gpio.h>
+
+class SpiTransport {
+public:
+    static constexpr size_t PACKET_SIZE = 256;
+
+    SpiTransport();
+    int init();
+
+    /**
+     * @brief Pulls handshake high and waits for the Pi to send 256 bytes.
+     * @return 0 on success, negative error code on failure.
+     */
+    int transfer_sync();
+
+    /**
+     * @brief Returns a pointer to the buffer containing the most recent data.
+     */
+    uint8_t* get_latest_data() { return buffers[processed_idx]; }
+
+private:
+    const struct device *spi_dev;
+    struct spi_config spi_cfg;
+    struct gpio_dt_spec handshake_gpio;
+
+    uint8_t buffers[2][PACKET_SIZE];
+    uint8_t active_idx = 0;    // Buffer currently being filled by SPI
+    uint8_t processed_idx = 1; // Buffer available for the app to read
+
+    void swap_buffers();
+};
+
+#endif

SPI_Slave_Driver/app.overlay

@@ -0,0 +1,9 @@
+&spi1 {
+    status = "okay";
+    pinctrl-0 = <&spi1_sck_pa5 &spi1_miso_pa6 &spi1_mosi_pa7 &spi1_nss_pa4>;
+    pinctrl-names = "default";
+    slave; 
+
+    /* Handshake Pin: STM32 pulls this high when spi_read is called */
+    handshake-gpios = <&gpiog 10 GPIO_ACTIVE_HIGH>; 
+};

flight_sim/.gitignore

@@ -0,0 +1,3 @@
+/build/
+
+/.cache

flight_sim/CMakeLists.txt

@@ -1,14 +1,28 @@
 cmake_minimum_required(VERSION 3.22)
 project(flight_sim LANGUAGES CXX)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g")
 
-find_package(Eigen3 3.4 REQUIRED NO_MODULE)
+find_package(Eigen3 REQUIRED NO_MODULE)
 find_package(Protobuf REQUIRED) # provides protobuf::libprotobuf and (often) protobuf::protoc
-find_package(nlohmann_json REQUIRED) # <-- add this (apt: nlohmann-json3-dev)
+# absl is a required dep of protobuf 6.x; add its include path globally
+foreach(_prefix /opt/homebrew /usr/local)
+  if(EXISTS "${_prefix}/include/absl")
+    include_directories(SYSTEM "${_prefix}/include")
+    message(STATUS "absl headers added from ${_prefix}/include")
+    break()
+  endif()
+endforeach()
+# nlohmann_json vendored as include/json.hpp (single-header amalgamation)
+
+
+# # DEBUG
+# get_target_property(EIGEN_INC Eigen3::Eigen INTERFACE_INCLUDE_DIRECTORIES)
+# message(STATUS "Eigen include path: ${EIGEN_INC}")
 
 # ---- Proto setup -------------------------------------------------------------
 
@@ -24,7 +38,7 @@ protobuf_generate(
   TARGET proto_lib
   LANGUAGE cpp
   PROTOS ${PROTO_FILES}
-  IMPORT_DIRS ${CMAKE_SOURCE_DIR}/../
+  IMPORT_DIRS ${CMAKE_SOURCE_DIR}/../ ${PROTO_DIR}
   PROTOC_OUT_DIR ${GEN_PROTO_DIR}
   APPEND_PATH OFF
 )
@@ -41,42 +55,22 @@ target_include_directories(proto_lib PUBLIC
 
 # ---- Executables ------------------------------------------------------------
 
-add_executable(json_test utils/json_utils.cpp)
-
-add_executable(${PROJECT_NAME}
-  src/main.cpp
-  src/physics/rigid_body.cpp
-)
-
-add_executable(UDPServer
-  src/UDPServer.cpp
-)
-
-add_executable(UDPClient
-  src/UDPClient.cpp
-)
+file(GLOB SRC_FILES "${CMAKE_SOURCE_DIR}/src/*.cpp")
+# SPI files use Linux kernel headers — exclude on non-Linux platforms
+if(NOT CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  list(FILTER SRC_FILES EXCLUDE REGEX ".*/spi_linux\\.cpp$")
+  list(FILTER SRC_FILES EXCLUDE REGEX ".*/spi_new_test\\.cpp$")
+endif()
 
-target_link_libraries(json_test
-  PRIVATE
-    nlohmann_json::nlohmann_json
-)
+add_executable(${PROJECT_NAME} ${SRC_FILES})
 
 target_link_libraries(${PROJECT_NAME}
   PRIVATE
     proto_lib
     Eigen3::Eigen
-    nlohmann_json::nlohmann_json
-)
-
-target_link_libraries(UDPServer
-  PRIVATE
-    proto_lib
-    nlohmann_json::nlohmann_json
 )
 
-target_link_libraries(UDPClient
-  PRIVATE
-    proto_lib
-    nlohmann_json::nlohmann_json
+target_include_directories(${PROJECT_NAME} PRIVATE
+  ${CMAKE_SOURCE_DIR}/include
 )