[SOLVED] AVR interrupt help (Serial receive)

jayanth.devarayanadurga · Dec 11, 2013

I am using ATMEGA16 and mikroC PRO AVR compiler. I need to know why serial reception using interrupts is not working. The UART transmit is working fine.

Code C - [expand]
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// LCD module connections
sbit LCD_RS at PORTB2_bit;
sbit LCD_EN at PORTB3_bit;
sbit LCD_D4 at PORTB4_bit;
sbit LCD_D5 at PORTB5_bit;
sbit LCD_D6 at PORTB6_bit;
sbit LCD_D7 at PORTB7_bit;
 
sbit LCD_RS_Direction at DDB2_bit;
sbit LCD_EN_Direction at DDB3_bit;
sbit LCD_D4_Direction at DDB4_bit;
sbit LCD_D5_Direction at DDB5_bit;
sbit LCD_D6_Direction at DDB6_bit;
sbit LCD_D7_Direction at DDB7_bit;
// End LCD module connections
 
 
unsigned char ackPacket[64] = "";
unsigned int i = 0;
unsigned char processAck = 0, cmd = 0;
 
#define Lo(param) ((char *)&param)[0]
#define Hi(param) ((char *)&param)[1]
#define Higher(param) ((char *)&param)[2]
#define Highest(param) ((char *)&param)[3]
 
const unsigned int gheader = 0xEF01;
unsigned long goriginalModuleAddress = 0xFFFFFFFF;
unsigned long gnewModuleAddress = 0xAABBCCDD;
unsigned long gmoduleAddress = 0xFFFFFFFF;
unsigned long gchipAddress = 0xFFFFFFFF;
unsigned long int gpassword = 0xABCDEF01;
unsigned short gturnOnPort = 1, gturnOffPort = 0;
unsigned short gbufferID = 0, gpageNum2 = 0;
unsigned int gpageID = 0, gnoOfTemplates = 0, gstartPage = 0, gpageNum = 0;
unsigned char gdataContent[32] = "";
 
void UART1_Write_Byte(unsigned char byte){
         UART1_Write(byte);
}
 
unsigned int findChecksum(unsigned char PID, unsigned int pLen, unsigned char instructionCode){
 
          return (PID + pLen + instructionCode);
}
 
void cmd_GenerateImage(const unsigned int header, unsigned long int moduleAddress, unsigned char PID, unsigned int pLen, unsigned char instructionCode);
 
 
 
//Finger Print Processing Functions
//Generate Image
void cmd_GenerateImage(const unsigned int header, unsigned long int moduleAddress, unsigned char PID, unsigned int pLen, unsigned char instructionCode){
 
    UART1_Write_Byte(Hi(header));
    UART1_Write_Byte(Lo(header));
 
    UART1_Write_Byte(Highest(moduleAddress));
    UART1_Write_Byte(Higher(moduleAddress));
    UART1_Write_Byte(Hi(moduleAddress));
    UART1_Write_Byte(Lo(moduleAddress));
 
    UART1_Write_Byte(PID);
    UART1_Write_Byte(Hi(pLen));
    UART1_Write_Byte(Lo(pLen));
 
    UART1_Write_Byte(instructionCode);
 
    UART1_Write_Byte((findChecksum(PID, pLen, instructionCode) >> 8));
    UART1_Write_Byte((findChecksum(PID, pLen, instructionCode) & 0xFF));
 
}
 
 
void Interrupt(){
 
     if(RXC_bit){
 
         if(cmd == 7){
                ackPacket[i] = UDR;
                i++;
         }
 
         if(i == 10)processAck = 1;
 
     }
     
     RXC_bit = 0;
}
 
 
 
void main() {
 
     DDRB = 0xFF;
     PORTB = 0x00;
     DDRD = 0xFE;
     PORTD = 0x00;
     
     UART1_Init(57600);
     Delay_ms(2000);
     
     RXCIE_bit = 1;
 
     asm{
     
          sei
     
     }
     
     Lcd_Init();                        // Initialize LCD
     Lcd_Cmd(_LCD_CLEAR);               // Clear display
     Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off
     Lcd_Out(1,1,"FP Scanner");                 // Write text in first row
 
 
     while(1){
     
           //Send some command to FP Scanner
            if(!processAck){
                    cmd = 7;
                    cmd_GenerateImage(gheader, gmoduleAddress, 0x01, 0x03, 0x01);
            }
            else if(processAck){
                    if(ackPacket[9] == 0x00)Lcd_Out(2,1,"Finger collection success");
                    else if(ackPacket[9] == 0x01)Lcd_Out(2,1,"Error when receiving Package");
                    else if(ackPacket[9] == 0x02)Lcd_Out(2,1,"Can't detect finger");
                    else if(ackPacket[9] == 0x03)Lcd_Out(2,1,"Fail to collect finger");
                    else if(ackPacket[0] == 'K')Lcd_Out(2,1,"Received...");
                    
                    processAck = 0;
                    i = 0;
                    cmd = 0;
            }
 
           Delay_ms(10000);
     
     }
}

Edit: The problem is solved. I used the mikroC PRO AVR interrupt assistant and it worked.

FvM · Dec 11, 2013

You'll notice that RXC bit is marked as readonly. It has to be always cleared by reading UDR. Exiting from ISR without reading UDR will cause a never ending ISR loop.

jayanth.devarayanadurga · Dec 11, 2013

My previous post updated.

Here is the working code.

Code C - [expand]
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// LCD module connections
sbit LCD_RS at PORTB2_bit;
sbit LCD_EN at PORTB3_bit;
sbit LCD_D4 at PORTB4_bit;
sbit LCD_D5 at PORTB5_bit;
sbit LCD_D6 at PORTB6_bit;
sbit LCD_D7 at PORTB7_bit;
 
sbit LCD_RS_Direction at DDB2_bit;
sbit LCD_EN_Direction at DDB3_bit;
sbit LCD_D4_Direction at DDB4_bit;
sbit LCD_D5_Direction at DDB5_bit;
sbit LCD_D6_Direction at DDB6_bit;
sbit LCD_D7_Direction at DDB7_bit;
// End LCD module connections
 
 
unsigned char ackPacket[64] = "";
unsigned int i = 0;
unsigned char processAck = 0, cmd = 0;
 
#define Lo(param) ((char *)&param)[0]
#define Hi(param) ((char *)&param)[1]
#define Higher(param) ((char *)&param)[2]
#define Highest(param) ((char *)&param)[3]
 
const unsigned int gheader = 0xEF01;
unsigned long goriginalModuleAddress = 0xFFFFFFFF;
unsigned long gnewModuleAddress = 0xAABBCCDD;
unsigned long gmoduleAddress = 0xFFFFFFFF;
unsigned long gchipAddress = 0xFFFFFFFF;
unsigned long int gpassword = 0xABCDEF01;
unsigned short gturnOnPort = 1, gturnOffPort = 0;
unsigned short gbufferID = 0, gpageNum2 = 0;
unsigned int gpageID = 0, gnoOfTemplates = 0, gstartPage = 0, gpageNum = 0;
unsigned char gdataContent[32] = "";
 
void UART1_Write_Byte(unsigned char byte){
         UART1_Write(byte);
}
 
unsigned int findChecksum(unsigned char PID, unsigned int pLen, unsigned char instructionCode){
 
          return (PID + pLen + instructionCode);
}
 
void cmd_GenerateImage(const unsigned int header, unsigned long int moduleAddress, unsigned char PID, unsigned int pLen, unsigned char instructionCode);
 
 
 
//Finger Print Processing Functions
//Generate Image
void cmd_GenerateImage(const unsigned int header, unsigned long int moduleAddress, unsigned char PID, unsigned int pLen, unsigned char instructionCode){
 
    UART1_Write_Byte(Hi(header));
    UART1_Write_Byte(Lo(header));
 
    UART1_Write_Byte(Highest(moduleAddress));
    UART1_Write_Byte(Higher(moduleAddress));
    UART1_Write_Byte(Hi(moduleAddress));
    UART1_Write_Byte(Lo(moduleAddress));
 
    UART1_Write_Byte(PID);
    UART1_Write_Byte(Hi(pLen));
    UART1_Write_Byte(Lo(pLen));
 
    UART1_Write_Byte(instructionCode);
 
    UART1_Write_Byte((findChecksum(PID, pLen, instructionCode) >> 8));
    UART1_Write_Byte((findChecksum(PID, pLen, instructionCode) & 0xFF));
 
}
 
void UART1_Interrupt() iv IVT_ADDR_USART_RXC ics ICS_AUTO {
 
      if(cmd == 7){
                ackPacket[i] = UDR;
                i++;
      }
 
      if(i == 10)processAck = 1;
 
      RXC_bit = 0;
}
 
void main() {
 
     DDRB = 0xFF;
     PORTB = 0x00;
     DDRD = 0xFE;
     PORTD = 0x00;
     
     UART1_Init(57600);
     Delay_ms(2000);
     
     RXCIE_bit = 1;
 
     asm{
         sei
     }
     
     Lcd_Init();                        // Initialize LCD
     Lcd_Cmd(_LCD_CLEAR);               // Clear display
     Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off
     Lcd_Out(1,1,"FP Scanner");                 // Write text in first row
 
 
     while(1){
     
            //Send some command to FP Scanner
            if(!processAck){
                    cmd = 7;
                    cmd_GenerateImage(gheader, gmoduleAddress, 0x01, 0x03, 0x01);
            }
            else if(processAck){
                    if(ackPacket[9] == 0x00){
                            Lcd_Out(2,1,"Finger collection   ");
                            Lcd_Out(3,1,"success             ");
                    }
                    else if(ackPacket[9] == 0x01){
                            Lcd_Out(2,1,"Error when receiving");
                            Lcd_Out(3,1,"Package             ");
                    }
                    else if(ackPacket[9] == 0x02){
                            Lcd_Out(2,1,"Can't detect finger ");
                    }
                    else if(ackPacket[9] == 0x03){
                            Lcd_Out(2,1,"Fail to collect     ");
                            Lcd_Out(3,1,"finger              ");
                    }
 
                    processAck = 0;
                    i = 0;
                    cmd = 0;
            }
 
           Delay_ms(5000);
     
     }
}

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[SOLVED] AVR interrupt help (Serial receive)

jayanth.devarayanadurga

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FvM

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jayanth.devarayanadurga

jayanth.devarayanadurga

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