The problem
- An external source sends these four bytes
0x2A, 0x42, 0x78, 0x25 - The PIC32 UART Does not generate an int
- The external source sends one more byte
- The PIC32 UART then generates an int
- In that int, Only the
0x25byte from the previous transmission appears - i.e., the first three disappear
- Once in awhile (Maybe 5% of the time) the UART does produce all 4 bytes properly
[Friday Evening Debug Results]
We wrote another echo routine; it just reads what it gets and writes it back out.
We built it in release mode (on advice of another here)
I wrote a routine to send the same number out 25 times, and see what I get back.
After that, I inc the value and send it out 25 times, and loop.
Results are appended at the end of this message.
I'm not getting the first null byte back. Based on various factors, I won't worry about that at this moment.
The next five rounds, I'm getting everything back perfectly
I'll try to include all relevant source code, hope it isn't a wall of text. If more code is needed to understand this, please ask.
This is the init code for the UART in question. I can include the
//*****************************************************************//
void initUART1(void) // UART1 for MCU1/2 communication
{
U1MODE=0; //// Mode Register, Manual DS61168D page 180
U1MODEbits.FRZ=0;
U1MODEbits.SIDL=0;
U1MODEbits.IREN=0;
U1MODEbits.RTSMD=0;
U1MODEbits.UEN=0b00; //// Just TX/RX, No CTS/RTS
U1MODEbits.WAKE=1;
U1MODEbits.LPBACK=0;
U1MODEbits.ABAUD=0;
U1MODEbits.RXINV=0;
U1MODEbits.BRGH=1;
U1MODEbits.PDSEL=0b00;
U1MODEbits.STSEL=0;
U1STA=0;
U1STAbits.ADM_EN=0;
U1STAbits.UTXINV=0;
U1STAbits.URXEN=1;
U1STAbits.UTXBRK=0;
U1STAbits.UTXEN=1;
U1STAbits.ADDEN=0;
U1STAbits.OERR=0;
//// Status register, Manual DS61168D page 183
//U1BRG=21; //// 21 for 921600 (80 MIPS)
U1BRG=172; //// 172 for 115200 (80 MIPS)
IFS0bits.U1RXIF=0;
IPC6bits.U1IP=5;
IPC6bits.U1IS=3;
IEC0bits.U1RXIE=1;
U1MODEbits.ON=1;
}
//*****************************************************************//
This is the interrupt service routine that handles this specific UART
//*********************************************************//
void __ISR(_UART1_VECTOR, ipl5) IntUart1Handler(void) //MCU communication port
{
if(INTGetFlag(INT_SOURCE_UART_RX(UART1))) //if it's a rx interrupt
{
U1RxBuf=UARTGetDataByte(UART1);
switch (CmdRecording)
{
case 0:
if(U1RxBuf=='*')
{
CmdRecording=1; //set the cmd recording flag
Command_U1[0]=U1RxBuf;
TimeOut=1; //time out=1 means the timeout for MCU1 command receiver is enabled
initT3(0x0100); //time out=0 means the timeout for MCU1 command receiver is enabled
}
else
{
putcharUART1('$');
putcharUART1('e');
putcharUART1('2');
putcharUART1('%');
}
break;
case 1:
CmdRecording=2; //set the cmd recording flag
Command_U1[1]=U1RxBuf;
break;
case 2:
CmdRecording=3; //set the cmd recording flag
Command_U1[2]=U1RxBuf;
break;
case 3:
CmdRecording=0; //reset the cmd recording flag
Command_U1[3]=U1RxBuf;
if(U1RxBuf=='%') //if this is the last command byte
{
if((Command_U1[1]=='O'))
{
CMD_Err=0; //clear error
CMD_OK=1; //send cmd OK;
}
else if((Command_U1[1]=='e'))
{
CMD_OK=0; //clear OK
CMD_Err=1; //send cmd Err;
}
else
Command_flag=1;
}
else
{
Command_flag=0;
}
disableT3(0); //the command receiving is done, disable the time out #0 (command receving time out)
TimeOut=0; //the command receiving is done, disable the time out
break;
default:
break;
}
INTClearFlag(INT_SOURCE_UART_RX(UART1));
}
if ( INTGetFlag(INT_SOURCE_UART_TX(UART1)) ) //if it's a tx interrupt
{
INTClearFlag(INT_SOURCE_UART_TX(UART1));
}
}
//***********************************************//
This is data that I saw when running the bytes through the "echo" system; i.e., the routine which reads one, writes one.
The PIC-32 is running at 80 MHz, and the UART is doing 115200 bps, so I'm not worried about the speed.
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01
02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02
03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03 03
04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04
05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 05
0x00, 0x00, 0x00, 0x00– User.1