update USB product string and include paths for CAN module. starting code with CAN as loopback to check if its working. not yet tested

firmware/components/CAN/CAN-B/.vscode/c_cpp_properties.json

@@ -19,6 +19,7 @@
                 "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/STM32F1xx_HAL_Driver/Inc",
                 "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/STM32F1xx_HAL_Driver/Src",
                 "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/CMSIS/DSP/Include",
+                "/home/kymkim/Projects/modular-kbd/firmware/components/CAN/CAN-B/.pio/libdeps/bluepill_f103c8/Unity/src",
                 "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/BSP/Components/Common",
                 "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/BSP/Components/ak4343",
                 "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/BSP/Components/cs43l22",
@@ -72,6 +73,7 @@
                     "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/STM32F1xx_HAL_Driver/Inc",
                     "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/STM32F1xx_HAL_Driver/Src",
                     "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/CMSIS/DSP/Include",
+                    "/home/kymkim/Projects/modular-kbd/firmware/components/CAN/CAN-B/.pio/libdeps/bluepill_f103c8/Unity/src",
                     "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/BSP/Components/Common",
                     "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/BSP/Components/ak4343",
                     "/home/kymkim/.platformio/packages/framework-stm32cubef1/Drivers/BSP/Components/cs43l22",

firmware/components/CAN/CAN-B/ModuleCAN.ioc

@@ -129,7 +129,7 @@ RCC.USBFreq_Value=48000000
 RCC.VCOOutput2Freq_Value=8000000
 USB_DEVICE.CLASS_NAME_FS=CDC
 USB_DEVICE.IPParameters=VirtualMode,VirtualModeFS,CLASS_NAME_FS,PRODUCT_STRING_CDC_FS
-USB_DEVICE.PRODUCT_STRING_CDC_FS=Modular Keyboard - Module VCOM
+USB_DEVICE.PRODUCT_STRING_CDC_FS=ModularKeyboardCOM
 USB_DEVICE.VirtualMode=Cdc
 USB_DEVICE.VirtualModeFS=Cdc_FS
 VP_SYS_VS_Systick.Mode=SysTick

firmware/components/CAN/CAN-B/Src/main.c

@@ -1,63 +1,24 @@
-/* USER CODE BEGIN Header */
+/*
-/**
+Sub-module CAN. Sends data to the master (CAN-A)
-  ******************************************************************************
+*/
-  * @file           : main.c
+
-  * @brief          : Main program body
-  ******************************************************************************
-  * @attention
-  *
-  * Copyright (c) 2025 STMicroelectronics.
-  * All rights reserved.
-  *
-  * This software is licensed under terms that can be found in the LICENSE file
-  * in the root directory of this software component.
-  * If no LICENSE file comes with this software, it is provided AS-IS.
-  *
-  ******************************************************************************
-  */
-/* USER CODE END Header */
-/* Includes ------------------------------------------------------------------*/
 #include "main.h"
 #include "can.h"
 #include "usb_device.h"
+#include "usbd_cdc_if.h"
+#include "string.h"
 #include "gpio.h"
 
-/* Private includes ----------------------------------------------------------*/
-/* USER CODE BEGIN Includes */
-
-/* USER CODE END Includes */
-
-/* Private typedef -----------------------------------------------------------*/
-/* USER CODE BEGIN PTD */
-
-/* USER CODE END PTD */
-
-/* Private define ------------------------------------------------------------*/
-/* USER CODE BEGIN PD */
-
-/* USER CODE END PD */
-
-/* Private macro -------------------------------------------------------------*/
-/* USER CODE BEGIN PM */
-
-/* USER CODE END PM */
-
-/* Private variables ---------------------------------------------------------*/
-
-/* USER CODE BEGIN PV */
-
-/* USER CODE END PV */
-
-/* Private function prototypes -----------------------------------------------*/
 void SystemClock_Config(void);
-/* USER CODE BEGIN PFP */
 
-/* USER CODE END PFP */
+CAN_TxHeaderTypeDef TxHeader;
+CAN_RxHeaderTypeDef RxHeader;
 
-/* Private user code ---------------------------------------------------------*/
+uint8_t TxData[8]; //Buffer for output data
-/* USER CODE BEGIN 0 */
+uint8_t RxData[8]; //Buffer for input data (probably will never get used)
 
-/* USER CODE END 0 */
+//Think of this as a location that will hold the pending data to send untill its ready.
+uint32_t TxMailbox; 
 
 /**
   * @brief  The application entry point.
@@ -66,43 +27,70 @@ void SystemClock_Config(void);
 int main(void)
 {
 
-  /* USER CODE BEGIN 1 */
 
-  /* USER CODE END 1 */
-
-  /* MCU Configuration--------------------------------------------------------*/
-
-  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
   HAL_Init();
-
-  /* USER CODE BEGIN Init */
-
-  /* USER CODE END Init */
-
-  /* Configure the system clock */
   SystemClock_Config();
 
+  /*
+    FIXME: USB CDC would be super useful in debugging. This might be also
+    Related to doing the USB HID since there are something going on with the
+    USB not getting detected on my device properly
+
+    At the mmoment, I'm getting device "address not responding" error using dmesg } grep usb
+    Some searching up hints that this is a common problem with Bluepills but because BP comes from many
+    Manufacturers its pretty hard to track it down to one problem. Can't find the schematic for ours too
+    The problem seems to be related to the resistor on the DP+ and DP- on the USB
+
+    Either that or we got a counterfiet STM32 board. I'll test it with a reputable brand to see. Other functionalities work though
+  */
   /* USER CODE BEGIN SysInit */
+  GPIO_InitTypeDef USB_RESISTOR = {0};
+  USB_RESISTOR.Pin = GPIO_PIN_12;
+  USB_RESISTOR.Mode = GPIO_MODE_OUTPUT_OD;
+  USB_RESISTOR.Pull = GPIO_NOPULL;
+  HAL_GPIO_Init(GPIOA,&USB_RESISTOR);
 
-  /* USER CODE END SysInit */
+  //Force Reset USB
+  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_12, GPIO_PIN_RESET);
+  HAL_Delay(50);
+  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_12, GPIO_PIN_SET);
   
-  /* Initialize all configured peripherals */
   MX_GPIO_Init();
   MX_CAN_Init();
+  
+  //Enables an interrupt when a data is recieved. 
+  //This includes your own data you sent so this is when filters comes to play
+  HAL_CAN_ActivateNotification(&hcan, CAN_IT_RX_FIFO0_MSG_PENDING);
+
+  HAL_CAN_Start(&hcan);
+
+  TxHeader.DLC = 1; //The lenght of data to send (in bytes)
+  TxHeader.ExtId = 0; //The ext. ID of the device
+  TxHeader.IDE = CAN_ID_STD; //No need for us to use ext. ID
+  TxHeader.RTR = CAN_RTR_DATA; //We are sending data...
+  TxHeader.StdId = 0x100; //The ID of this module is now 100. Any devices with a filter matching this ID would read it
+  TxHeader.TransmitGlobalTime = DISABLE; 
+
+  //Sample message send
+  TxData[0] = 0xf1;  
+
   MX_USB_DEVICE_Init();
-  /* USER CODE BEGIN 2 */
 
-  /* USER CODE END 2 */
-
-  /* Infinite loop */
-  /* USER CODE BEGIN WHILE */
   while (1)
   {
-    /* USER CODE END WHILE */
+    HAL_CAN_AddTxMessage(&hcan, &TxHeader, TxData, &TxMailbox);
-
+    HAL_Delay(1000);
-    /* USER CODE BEGIN 3 */
   }
-  /* USER CODE END 3 */
+
+}
+
+void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
+{
+  //Read message from the RxCAN and store it on RxHeader
+  HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &RxHeader, RxData);
+  HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
+  char *buf = RxData[0];
+  CDC_Transmit_FS((uint8_t *)buf,strlen(buf));
 }
 
 /**

firmware/components/CAN/CAN-B/Src/usbd_desc.c

@@ -66,7 +66,7 @@
 #define USBD_LANGID_STRING     1033
 #define USBD_MANUFACTURER_STRING     "STMicroelectronics"
 #define USBD_PID_FS     22336
-#define USBD_PRODUCT_STRING_FS     "Modular Keyboard - Module VCOM"
+#define USBD_PRODUCT_STRING_FS     "ModularKeyboardCOM"
 #define USBD_CONFIGURATION_STRING_FS     "CDC Config"
 #define USBD_INTERFACE_STRING_FS     "CDC Interface"