Виртуальный COM-порт на STM32 или как управлять контроллером через USB не привлекая внимания санитаров17.06.2022 13:01

void USB_LP_CAN1_RX0_IRQHandler(){
	BKIstr = ISTR;
	if(BKIstr & ISTR_CTR){
		CTR_LP_CTRX();
	}  
	if(BKIstr & ISTR_RESET){
		USB_RESET();
	}
}

#define ISTR_CTR		0x8000
#define ISTR_EP_ID	0x000F
#define EP_CTR_TX		0x0080
#define EP_CTR_RX		0x8000
#define USB_EP0_MAX_PACKET_SIZE	0x0040

void CTR_LP_CTRX() {
uint16_t TempEP;
uint8_t Related_Endpoint, Reserved;
uint16_t USB_wIndex;

while (((BKIstr = ISTR) & ISTR_CTR)) {
    // extract highest priority endpoint number 
    EPindex = (uint8_t)(BKIstr & ISTR_EP_ID);

  if (EPindex == 1 && (EP1R & EP_CTR_TX)){ //CDC Transmit
      EP1R &= 0x8F0F;
      USB_Function_flags |= 1;
	} else if (EPindex == 3 && (EP3R & EP_CTR_RX)){ //CDC Receive
			USB_Function_flags &= 0xEF;
			USB_RX_Start_pointer = 0;

			//you can save up current time
    	//in case you have a limited timeframe for processing this data
    	EP3R = (EP3R ^ 0x2000) & 0x3F8F;
    	USB_Recieved_bytes = (PMA_BUF(15)&0x3FF);
    	TO_READ_PMA(EP3RX_OFFSET, USB_Buff1, 64,64);
			USB_Function_flags |= 2;

        // Decode and service non control endpoints interrupt 
        // process related endpoint register 

    } else if(EPindex == 0){

        // Decode and service control endpoint interrupt 
        // calling related service routine 
        // (Setup0_Process, In0_Process, Out0_Process) 

        // save RX & TX status 
        // and set both to NAK 

  	    SaveTState = EP0R & 0x3030;

  	    EP0R = (EP0R^0x2020)&0xBFBF;
        // DIR bit = origin of the interrupt 
        if (BKIstr & ISTR_DIR) {
            // DIR = 1 */
            // DIR = 1 & CTR_RX       => SETUP or OUT int 
            // DIR = 1 & (CTR_TX | CTR_RX) => 2 int pending 
            	EP0R &=0x0F8F;// SETUP bit kept frozen while CTR_RX = 1 
            	USB_state_flag = STALLED;
            if (EP0R & EP_SETUP) {

              USB_Command = PMA_SBUF(EP0RX_OFFSET);
              USB_wValue  = PMA_SBUF(EP0RX_OFFSET+2);
              USB_wIndex  = PMA_SBUF(EP0RX_OFFSET+4);
              USB_wLength = PMA_SBUF(EP0RX_OFFSET+6);
              if (USB_wLength == 0)
              {
                // Setup with no data stage 

            	  USB_state_flag = WAIT_STATUS_IN;// After no data stage SETUP
            	  PMA_BUF(1) = 0;
            	  if (USB_Command == 0x0900){    // SET_CONFIGURATION
            			  USB_Configuration = USB_wValue;
            	  } else if (USB_Command == 0x0500){//SET ADDRESS
            		  USB_DADDR = USB_wValue | DADDR_EF;
            	  } else if ((USB_Command &0xFDFF) == 0x0100){//SET FEATURE for Device 0300, CLEAR FEATURE for Device 0100

            	  } else if (USB_Command == 0x0B01 && (USB_Configuration) && ((USB_wIndex & 0xFF) <= 1)){//SET INTERFACE
            			  USB_Interface = USB_wIndex;
            	  } else if (USB_Command == 0x0102){
            		  //EndPoint Clear Feature
            		  Related_Endpoint = USB_wIndex & 0x7F;
            	      if ((USB_wValue == 0)//ENDPOINT_STALL)
            	          && (USB_wIndex > 0x100) && USB_Configuration)
            	      {
            		        //Get Status of endpoint & stall the request if the related_ENdpoint
            		        is Disabled
            	    	  TempEP = ENDPOINT(Related_Endpoint);
            	    	  if (USB_wIndex & 0x80) {
            	    		  // IN endpoint 
            			      if ((TempEP&0x0030)==0x0010)
            			      {
            			          ENDPOINT(Related_Endpoint) = (TempEP ^ 0x0030)&0x8FFF;
            			      }
            		      } else {
            		    	  // OUT endpoint
            		    	  if ((TempEP&0x3000)==0x1000)
            		    	  {
            		    		  if (Related_Endpoint == 0)
            			          {
            			            // After clear the STALL, enable the default endpoint receiver 
            			        	  PMA_BUF(3) = 0x8400;
            			        	  EP0R = (EP0R ^ 0x3000)&0xBF8F;
            			          }
            			          else
            			          {
            			            ENDPOINT(Related_Endpoint) = (TempEP ^ 0x3000)&0xFF8F;
            			          }
            		    	  }
            		      }
            	      }
            	  } else if (USB_Command == 0x0302){
									// get Status of endpoint & stall the request if the related_ENdpoint is Disabled
            	      Related_Endpoint = USB_wIndex & 0x7F;
            	      if ((USB_wValue==0) && USB_Configuration){
            	    	  TempEP = ENDPOINT(Related_Endpoint);
            	    	  if (USB_wIndex & 0x80) {
            				    
            				    if(TempEP&0x0030){
            				    	ENDPOINT(Related_Endpoint) = (TempEP ^ 0x0010)&0x8FBF;
            				    }
            			  } else {
            				    if(TempEP&0x3000){
            				    	ENDPOINT(Related_Endpoint) = (TempEP ^ 0x1000)&0xBF8F;
            				    }
            			  }
            	      }

            	  } else if ((USB_Command & 0xDDFF) == 0x0021){
                  //SET_COMM_FEATURE 0221
                  //SET_CONTROL_LINE_STATE 2221
                  //SET Linecoding 2021
         
                  USB_Message("Device connected\r\0",1);
            		  USB_main_COM_react();

            	  } else {
            		  USB_state_flag = STALLED;
            	  }

            	  SaveTState |= 0x0030;
              } else {
                // Setup with data stage 
            	  USB_state_flag =  LAST_IN_DATA;
            	  PMA_BUF(1) = USB_wLength;
            		if (USB_Command == 0x0680){//GET DESCRIPTOR
            		      if (USB_wValue == 0x0100){
            		    	  TO_WRITE_PMA(DeviceDiscriptor,EP0TX_OFFSET,0x12,USB_EP0_MAX_PACKET_SIZE);
            		    	  PMA_BUF(1)= 0x12;
            		      } else if (USB_wValue == 0x0200){
            		    	  TO_WRITE_PMA(ConfigDescriptor,EP0TX_OFFSET,64,USB_EP0_MAX_PACKET_SIZE);

            		    	  if (USB_wLength>9){
                          
            		    		  PMA_BUF(1)= USB_EP0_MAX_PACKET_SIZE;
            		    		  USB_state_flag = IN_DATA;
            		    	  }
							  
            		      } else if (USB_wValue == 0x0300){
            		    	  PMA_SBUF(EP0TX_OFFSET) = 0x0304; // 3 - string descriptor, N=4
            		    	  PMA_SBUF(EP0TX_OFFSET + 2) = 0x0409;//Lang ID - US
            		    	  PMA_BUF(1)= 4;
            		      } else if (USB_wValue == 0x0301){
            		    	  USB_Message("VENDOR\0",0);
            		      } else if (USB_wValue == 0x0302){
            		    	  USB_Message("Device name\0",0);
            		      } else if (USB_wValue == 0x0303){
            		    	  uint32_t buf1 = *(__IO uint32_t*)(0x1FFFF7F0);//get unique chip ID
            		    	  for (Reserved = 2; Reserved<24; Reserved+=2){
            		    		  PMA_SBUF(EP0TX_OFFSET + Reserved)= (buf1 & 0x7) + '0';
            		    		  buf1 >>= 3;
            		    	  }
            		    	  PMA_SBUF(EP0TX_OFFSET)= 0x0318;
            		    	  PMA_BUF(1)=24;
            		      }// End of GET_DESCRIPTOR
            		} else if ((USB_Command&0xFFFE) == 0x0080){// GET STATUS for Device, GET STATUS for Interface
            			Reserved = 0;
            			if (USB_Command == 0x0080){
            			    if (USB_Feature & 0x20){// is Remote Wakeup enabled?
            			    	Reserved |= 2;
            			    }
            			    if (USB_Feature & 0x40){// is Bus-powered?
            			    	Reserved |= 1;
            			    }
            			}
            			PMA_SBUF(EP0TX_OFFSET) = Reserved; 
            		} else if (USB_Command == 0x0082){// GET STATUS for EndPoint
            			Related_Endpoint = USB_wIndex & 0x7F;
            			PMA_SBUF(EP0TX_OFFSET) =0;
            			TempEP = ENDPOINT(Related_Endpoint);
           				if (USB_wIndex & 0x80) {
            					// get Status of endpoint & stall the request if the related_ENdpoint is Disabled
            					if(TempEP&0x0030 == 0x0010){
            						PMA_SBUF(EP0TX_OFFSET) =1;// IN Endpoint stalled 
            					}
            				} else {
            					if(TempEP&0x3000 == 0x1000){
            						PMA_SBUF(EP0TX_OFFSET) =1;//OUT Endpoint stalled 
            					}
            				}

            		} else if (USB_Command == 0x0880){//GET CONFIGURATION
            			PMA_SBUF(EP0TX_OFFSET) = USB_Configuration;

            		} else if ((USB_Command & 0xFE7F) == 0x2021){
                  //Get (21A1)/set (20A1) Line Coding
            			PMA_BUF(EP0TX_OFFSET) = 9600;//baudrate
            			PMA_SBUF(EP0TX_OFFSET+4) = 0;//parity*256+format
            			PMA_SBUF(EP0TX_OFFSET+6) = 8;//datatype
            		} else {
            			USB_state_flag = STALLED;
            		}
            	    SaveTState = (0x3030);
               }
            }
        } else {
            // DIR = 0 
            // DIR = 0      => IN  int 
            // DIR = 0 implies that (EP_CTR_TX = 1) always  
        	EP0R &=0x8F0F;

        	if (USB_state_flag == IN_DATA){
            //last 3 bytes of Config Descriptor
            //no need to use procedure as there is only 2 assignments
		    		PMA_SBUF(EP0TX_OFFSET) = 0x0040;
		    		PMA_SBUF(EP0TX_OFFSET + 2) = 0;
		    		USB_state_flag =  LAST_IN_DATA;
		    		PMA_BUF(1)= 3;
		    		SaveTState = (0x3030);
        	} else if (USB_state_flag == LAST_IN_DATA){
        		USB_state_flag = WAIT_STATUS_OUT;
      			SaveTState = (0x3010);
        	} else {
        		if (USB_DADDR){//SetDeviceAddress
        			for (Reserved = 0; Reserved < EP_NUM; Reserved++) {
        				ENDPOINT(Reserved) = (ENDPOINT(Reserved) & 0x8F80) | Reserved ;
        			}
        			DADDR = USB_DADDR; // set device address and enable device function
        			USB_DADDR = 0;
        		}
        		USB_state_flag = STALLED;
        	}

        }
        PMA_BUF(3) = 0x8400;
       
        if (USB_state_flag == STALLED) SaveTState = 0x1010;

        EP0R = (EP0R^(SaveTState))&0xBFBF;
        return;
    }

  }
}

Поместить данные (пакет не больше чем USB_EP1_MAX_PACKET_SIZE_TX) в рабочий буфер USB_COM_TX_Buff1,

записать в переменную USB_Bytes_to_send_left количество отправляемых байт в текущем пакете

Вызвать процедуру

#define USB_EP1_MAX_PACKET_SIZE_TX	0x40

//фактическая отправка данных хосту
//данные и их количество записаны в USB_COM_TX_Buff1
//и в USB_Bytes_to_send_left соответственно.
void USB_main_COM_react(){

	if (USB_Bytes_to_send_left){
		//send pack back to the Host
		USB_Function_flags &= 0xFE;
		TO_WRITE_PMA(USB_COM_TX_Buff1 ,EP1TX_OFFSET, 64, USB_EP1_MAX_PACKET_SIZE_TX);
		PMA_BUF(5) = USB_Bytes_to_send_left;
		EP1R = (EP1R^0x0030)&0x8FBF;
		USB_Bytes_to_send_left = 0;

		uint32_t i = 5000;
		while (((EP1R & 0x80) == 0) && (i)) {i--;}
  }
}

Данные лежат в массиве USB_Buff1

их количество записано в переменной USB_Recieved_bytes

после обработки выполнить этот код:

PMA_BUF(15) = 0x8400;
EP3R = (EP3R^0x3000)&0xBF8F;

Из прерывания мы вошли в процедуру и в цикл внутри этой процедуры. Выяснили, что у нас 0 конечная точка. На всякий случай сохраняем состояние приёма и передачи (SaveTState = EP0R & 0×3030), а затем переводим нулевую конечную точку в состояние NAK (обработка данных) и по каналу приёма, и по каналу передачи. Так у нас будет время сформировать ответ хосту.

На этом этапе направление передачи (ISTR_DIR) должно быть OUT (бит поднят), Бит EP_SETUP поднят. Бит EP_CTR_RX тоже поднят (его опускаем).

Копируем данные из области PMA, размеченной для приёма в рабочие переменные. Это будет команда USB_Command = PMA_SBUF (EP0RX_OFFSET);
параметр USB_wValue = PMA_SBUF (EP0RX_OFFSET+2);
индекс USB_wIndex = PMA_SBUF (EP0RX_OFFSET+4);
и длина требуемого ответа USB_wLength = PMA_SBUF (EP0RX_OFFSET+6);