Tailor to ESP32-EVB

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/.vscode/c_cpp_properties.json

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+{
+    "configurations": [
+        {
+            "name": "Win32",
+            "includePath": [
+                "${workspaceFolder}/**"
+            ],
+            "defines": [
+                "_DEBUG",
+                "UNICODE",
+                "_UNICODE"
+            ],
+            "cStandard": "c17",
+            "cppStandard": "c++17",
+            "intelliSenseMode": "windows-msvc-x64",
+            "compileCommands": "${workspaceFolder}/build/compile_commands.json"
+        }
+    ],
+    "version": 4
+}

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/.vscode/settings.json

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+{
+    "idf.adapterTargetName": "esp32",
+    "files.associations": {
+        "can.h": "c",
+        "twai.h": "c",
+        "can_types.h": "c",
+        "twai_types.h": "c"
+    },
+    "idf.flashType": "UART",
+    "idf.portWin": "COM6"
+}

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/CMakeLists.txt

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+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.5)
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(can_basic)

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/Makefile

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+#
+# This is a project Makefile. It is assumed the directory this Makefile resides in is a
+# project subdirectory.
+#
+
+PROJECT_NAME := can_basic
+
+include $(IDF_PATH)/make/project.mk

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/README.md

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+| Supported Targets | ESP32 | 
+| ----------------- | ----- | 
+
+# CAN Example
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+## Overview
+
+This example demonstrates basic usage of `CAN driver`. The work flow of the example could be as follows:
+
+1. Install CAN driver
+2. Receive CAN messages
+3. Send CAN message
+4. Enable filter and receive only filtered messages (not implemented)
+
+Code was heavily based on https://docs.espressif.com/projects/esp-idf/en/release-v3.3/api-reference/peripherals/can.html
+
+If you have a new CAN application to create (for example, J1939 communication to a tank), try this as a basic template, then add your own code.
+
+## How to use example
+See Build, Flash, and Run below.
+
+### Hardware Required
+
+This example assumes you have an Olimex ESP32-EVB and was tested with a REV I version. 
+
+#### Pin Assignment
+
+This example uses the embedded ESP32 CAN/TWAI controller. On the ESP32-EVB the pins are assigned as
+
+* CAN-TX is on GPIO5
+* CAN-RX is on GPI35
+
+In the example code, these assignments are hard-coded.
+
+### Configure the project
+
+```
+idf.py menuconfig
+```
+No configuration options have been set up.
+
+The CAN transceiver is a MCP2562-E/SN. By default on the ESP32-EVB it operates on the +5V sourced from the PWR2 connector or USB connector.
+
+
+### Build, Flash, and Run
+
+Build the project and flash it to the board, then run monitor tool to view serial output. Use a CAN monitoring tool to see the transmitted message.
+
+```
+idf.py -p PORT build flash monitor
+```
+
+(Replace PORT with the name of the serial port to use.)
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+See the [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects.
+
+## Example Output
+
+```bash
+Driver installed
+Driver started
+Message received
+Message is in Extended Format
+ID:1CEBFFFA, data:2 90 E7 FF FF FF FF FF
+Message queued for transmission
+ESP_ERR_TIMEOUT
+```
+
+## Troubleshooting
+
+See common troubleshooting for examples from [upper level](../README.md#common-troubleshooting).
+
+(For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you as soon as possible.)

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/main/CMakeLists.txt

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+idf_component_register(SRCS "can_example_main.c"
+                       INCLUDE_DIRS ".")

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/main/Kconfig.projbuild

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+

SOFTWARE/ESP-IDF_examples/ESP32-EVB_CAN/main/can_example_main.c

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+// Code based on example at
+// https://docs.espressif.com/projects/esp-idf/en/release-v3.3/api-reference/peripherals/can.html
+// which is Copyright 2015-2021 Espressif Systems (Shanghai) PTE LTD
+//
+// All other example code Copyright 2022 Brian Alano and 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.#include <stdio.h>
+
+#include "driver/gpio.h"
+// #include "driver/can.h"
+#include "driver/twai.h"
+
+//#include "sdkconfig.h"
+
+static const char *TAG = "can_example";
+
+esp_err_t recv() {
+    //Wait for message to be received
+    twai_message_t message; 
+    if (twai_receive(&message, pdMS_TO_TICKS(10000)) == ESP_OK) {
+        printf("Message received\n");
+    } else {
+        printf("Failed to receive message\n");
+        return;
+    }
+
+    //Process received message
+    if (message.flags & TWAI_MSG_FLAG_EXTD) {
+        printf("Message is in Extended Format\n");
+    } else {
+        printf("Message is in Standard Format\n");
+    }
+    printf("ID:%X, data:", message.identifier);
+    if (!(message.flags & TWAI_MSG_FLAG_RTR)) {
+        for (int i = 0; i < message.data_length_code; i++) {
+            printf("%X ", message.data[i]);
+        }
+        printf("\n");
+    }
+}
+
+esp_err_t transmit(twai_message_t *message) {
+    //Queue message for transmission
+    if (twai_transmit(message, pdMS_TO_TICKS(1000)) == ESP_OK) {
+        printf("Message queued for transmission\n");
+        return ESP_OK;
+    } else {
+        printf("Failed to queue message for transmission\n");
+        return ESP_FAIL;
+    }
+}
+
+void app_main()
+{
+    uint32_t my_alerts = 0;
+    esp_err_t ret; 
+    twai_message_t message;
+    message.identifier = 0x18FF1720;
+    message.flags = TWAI_MSG_FLAG_EXTD;
+    message.data_length_code = 8;
+    for (int i = 0; i < 8; i++) {
+        message.data[i] = 0xff;
+    }
+    uint32_t cnt = 0;
+
+    //Initialize configuration structures using macro initializers
+    twai_general_config_t g_config = TWAI_GENERAL_CONFIG_DEFAULT(GPIO_NUM_5, GPIO_NUM_35, TWAI_MODE_NORMAL);
+    twai_timing_config_t t_config = TWAI_TIMING_CONFIG_250KBITS();
+    twai_filter_config_t f_config = TWAI_FILTER_CONFIG_ACCEPT_ALL();
+
+    ret = twai_reconfigure_alerts(TWAI_ALERT_ALL || TWAI_ALERT_AND_LOG, &my_alerts);
+    if (ret == ESP_OK) {
+        printf("Alerts reconfigured\n");
+    } else {
+        printf("Failed to reconfigure alerts. Err:%d", ret);
+    }
+
+    //Install CAN driver
+    if (twai_driver_install(&g_config, &t_config, &f_config) == ESP_OK) {
+        printf("Driver installed\n");
+    } else {
+        printf("Failed to install driver\n");
+        return;
+    }
+
+    //Start CAN driver
+    if (twai_start() == ESP_OK) {
+        printf("Driver started\n");
+    } else {
+        printf("Failed to start driver\n");
+        return;
+    }
+
+     while(true) {
+        recv();
+        message.data[0] = (uint8_t)(cnt >>24);
+        message.data[1] = (uint8_t)(cnt >>16);
+        message.data[2] = (uint8_t)(cnt >>8);
+        message.data[3] = (uint8_t)(cnt);
+        transmit(&message);
+        ret = twai_read_alerts(&my_alerts, 10);
+        if ( ret == ESP_OK) {
+            printf("ESP_OK. alerts:%x\n", my_alerts);
+        } else if (ret == ESP_ERR_TIMEOUT) {
+            printf("ESP_ERR_TIMEOUT\n");
+        } else {
+            printf("unexpected twai alert: %d\n", ret);
+        }
+        cnt++;
+    };
+
+
+}