test for can bus hardware

.gitmodules

 [submodule "firmware/pico-ssd1306"]
 	path = firmware/pico-ssd1306
 	url = https://github.com/xythobuz/pico-ssd1306
+[submodule "firmware/can2040"]
+	path = firmware/can2040
+	url = https://github.com/KevinOConnor/can2040

README.md

 It uses the [Pi Pico SDK](https://github.com/raspberrypi/pico-sdk), licensed as BSD 3-clause, and therefore also [TinyUSB](https://github.com/hathach/tinyusb), licensed under the MIT license.
 Some code is adapted from the TinyUSB examples.
 To control the OLED display, [pico-ssd1306](https://github.com/daschr/pico-ssd1306) is used, licensed under the MIT license.
+The CAN bus PIO implementation is [can2040](https://github.com/KevinOConnor/can2040), licensed under the GPLv3.
 Repo metadata is embedded into the project using [cmake-git-version-tracking](https://github.com/andrew-hardin/cmake-git-version-tracking), licensed under the MIT license.
 
     This program is free software: you can redistribute it and/or modify

firmware/CMakeLists.txt

     ${CMAKE_CURRENT_LIST_DIR}/src/lcd.c
     ${CMAKE_CURRENT_LIST_DIR}/src/ring.c
     ${CMAKE_CURRENT_LIST_DIR}/src/hw_id.c
+    ${CMAKE_CURRENT_LIST_DIR}/src/can.c
 
     ${CMAKE_CURRENT_LIST_DIR}/pico-ssd1306/ssd1306.c
+
+    ${CMAKE_CURRENT_LIST_DIR}/can2040/src/can2040.c
 )
 
 target_include_directories(dispensy PUBLIC ${CMAKE_CURRENT_LIST_DIR}/include)
+
 target_include_directories(dispensy PUBLIC ${CMAKE_CURRENT_LIST_DIR}/pico-ssd1306)
 
+target_include_directories(dispensy PUBLIC ${CMAKE_CURRENT_LIST_DIR}/can2040/src)
+target_include_directories(dispensy PUBLIC ${CMAKE_CURRENT_LIST_DIR}/pico-sdk/src/rp2_common/cmsis/stub/CMSIS/Device/RaspberryPi/RP2040/Include)
+target_include_directories(dispensy PUBLIC ${CMAKE_CURRENT_LIST_DIR}/pico-sdk/src/rp2_common/cmsis/stub/CMSIS/Core/Include)
+
 # enable generous warnings
 target_compile_options(dispensy PUBLIC
     -Wall
     -Wextra
     -Werror
-    -Wshadow
+
+    -O3
 
     -DSSD1306_DEBUG_PRINT=debug
     -DSSD1306_DEBUG_INCLUDE="log.h"
 )
 
 # suppress some warnings for borked 3rd party files in Pico SDK
-set_source_files_properties(pico-sdk/lib/btstack/src/ble/sm.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
-set_source_files_properties(pico-sdk/lib/btstack/src/btstack_hid_parser.c PROPERTIES COMPILE_FLAGS -Wno-maybe-uninitialized)
-set_source_files_properties(pico-sdk/src/rp2_common/pico_cyw43_driver/cyw43_driver.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
-set_source_files_properties(pico-sdk/lib/btstack/src/classic/avdtp_util.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
-set_source_files_properties(pico-sdk/lib/btstack/src/classic/goep_client.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
-set_source_files_properties(pico-sdk/lib/btstack/src/classic/goep_server.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
-set_source_files_properties(pico-sdk/src/rp2_common/hardware_flash/flash.c PROPERTIES COMPILE_FLAGS -Wno-shadow)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/lib/btstack/src/ble/sm.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/lib/btstack/src/btstack_hid_parser.c PROPERTIES COMPILE_FLAGS -Wno-maybe-uninitialized)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/src/rp2_common/pico_cyw43_driver/cyw43_driver.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/lib/btstack/src/classic/avdtp_util.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/lib/btstack/src/classic/goep_client.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/lib/btstack/src/classic/goep_server.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/pico-sdk/src/rp2_common/hardware_flash/flash.c PROPERTIES COMPILE_FLAGS -Wno-shadow)
+
+set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/can2040/src/can2040.c PROPERTIES COMPILE_FLAGS -Wno-unused-parameter)
 
 # repo meta data
 include(FetchContent)

firmware/README.md

 
     sudo pacman -S arm-none-eabi-gcc arm-none-eabi-newlib picocom cmake cxxtest
 
+## Sniffing the CAN Bus
+
+Using a USB CAN adapter that is supported in Linux, [like the UCAN](https://www.fysetc.com/en-de/products/fysetc-ucan-board-based-on-stm32f072-usb-to-can-adapter-support-with-canable-candlelight-klipper-firmware), you can easily interact with the CAN bus.
+
+You need to install the [can-utils](https://github.com/linux-can/can-utils) in your Linux distro.
+
+After plugging the adapter in, bring up the CAN network interface and dump all received packets:
+
+    sudo ip link set can0 type can bitrate 1000000
+    sudo ip link set up can0
+    candump can0
+
 ## Proper Debugging
 
 You can also use the SWD interface for proper hardware debugging.

firmware/can2040

+Subproject commit 9e761ae353ea473e24c8bba226e10afad8a919ff

firmware/include/can.h

+/*
+ * can.h
+ *
+ * Copyright (c) 2024 Thomas Buck (thomas@xythobuz.de)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * See <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __CAN_H__
+#define __CAN_H__
+
+void can_init(void);
+
+void can_hello(void);
+
+#endif // __CAN_H__

firmware/src/can.c

+/*
+ * can.c
+ *
+ * Copyright (c) 2024 Thomas Buck (thomas@xythobuz.de)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * See <http://www.gnu.org/licenses/>.
+ */
+
+#include "can2040.h"
+#include "RP2040.h"
+
+#include "config.h"
+#include "log.h"
+#include "can.h"
+
+#define PIO_IRQ PIO0_IRQ_0_IRQn
+static const uint pio_num = 0;
+static const uint sys_clock = 125UL * 1000UL * 1000UL;
+static const uint bitrate = 1000UL * 1000UL;
+static const uint gpio_rx = 25;
+static const uint gpio_tx = 24;
+
+static struct can2040 bus;
+
+static void can2040_cb(struct can2040 *cd, uint32_t notify, struct can2040_msg *msg) {
+    (void)cd;
+
+    switch (notify) {
+        case CAN2040_NOTIFY_RX: {
+            debug("rx id=%" PRIX32 " dlc=%" PRIX32 " data=0x%08" PRIX32 "%08" PRIX32,
+                  msg->id, msg->dlc, msg->data32[0], msg->data32[1]);
+            break;
+        }
+
+        case CAN2040_NOTIFY_TX: {
+            debug("tx id=%" PRIX32 " dlc=%" PRIX32 " data=0x%08" PRIX32 "%08" PRIX32,
+                  msg->id, msg->dlc, msg->data32[0], msg->data32[1]);
+            break;
+        }
+
+        case CAN2040_NOTIFY_ERROR: {
+            debug("err id=%" PRIX32 " dlc=%" PRIX32 " data=0x%08" PRIX32 "%08" PRIX32,
+                  msg->id, msg->dlc, msg->data32[0], msg->data32[1]);
+            break;
+        }
+    }
+}
+
+static void PIOx_IRQHandler(void) {
+    can2040_pio_irq_handler(&bus);
+}
+
+void can_init(void) {
+    can2040_setup(&bus, pio_num);
+    can2040_callback_config(&bus, can2040_cb);
+
+    irq_set_exclusive_handler(PIO_IRQ, PIOx_IRQHandler);
+    NVIC_SetPriority(PIO_IRQ, 1);
+    NVIC_EnableIRQ(PIO_IRQ);
+
+    can2040_start(&bus, sys_clock, bitrate, gpio_rx, gpio_tx);
+}
+
+void can_hello(void) {
+    static uint32_t prev = 0;
+    uint32_t now = to_ms_since_boot(get_absolute_time());
+
+    if ((now - prev) >= 1000) {
+        prev = now;
+        struct can2040_msg msg = {0};
+        msg.id = 0x42;
+        int r = can2040_transmit(&bus, &msg);
+        if (r != 0) {
+            debug("error sending msg: %d", r);
+        }
+    }
+}

firmware/src/main.c

 #include "buttons.h"
 #include "lcd.h"
 #include "hw_id.h"
+#include "can.h"
 #include "main.h"
 
 void main_loop_hw(void) {
     lcd_init();
     lcd_splash_version();
 
+    can_init();
+
     debug("go");
 
     while (1) {
+        can_hello();
+
         main_loop_hw();
         //buttons_run();
         cnsl_run();