Interrupt handling for a UART on PIC32 with C32 v2.00 compiler

Question

I am very new to PIC32 chips (or any PIC chips) and I am trying to create an interrupts handler for the UART to be called when the UART receive a byte. I am using the PIC32MX695F512L PIC32 processor with C32 2.00 compiler on a development board.

I found this example code in another project online. The comments led me to belive that this interrupt would be called whenever the UART receives a byte. I added a break point to this function and a static counter to count how many times this function has been run.

In other parts of the source code I can send BYTES out of the UART and are being revived by my PC. I have tried sending BYTES to the UART from my PC but this function is never triggered and the function counter (UART1Info_count) never increases.

Source code

static BYTE UART1Info_LastByteRXed ;
static UINT32 UART1Info_count ; // Init elsewhere 

BOOL Uart_Connect ( ) {

    UART1Info_count = 0 ; 
    UART1Init();

    UARTConfigure       (UART1, UART_ENABLE_PINS_TX_RX_ONLY);
    UARTSetFifoMode     (UART1, UART_INTERRUPT_ON_RX_NOT_EMPTY);
    UARTSetLineControl  (UART1, UART_DATA_SIZE_8_BITS | UART_PARITY_NONE | UART_STOP_BITS_1 );
    UARTSetDataRate     (UART1, GetPeripheralClock(), 9600) ;
    UARTEnable          (UART1, UART_ENABLE_FLAGS(UART_PERIPHERAL | UART_RX | UART_TX));

    INTEnable           (INT_SOURCE_UART_RX(UART1), INT_ENABLED);
    INTEnable           (INT_SOURCE_UART_TX(UART1), INT_ENABLED);


    // Set Interrupt priorities    
    INTSetVectorPriority    (INT_VECTOR_UART(UART1), INT_PRIORITY_LEVEL_2);
    INTSetVectorSubPriority (INT_VECTOR_UART(UART1), INT_SUB_PRIORITY_LEVEL_0);

    // configure for multi-vectored mode
    INTConfigureSystem      (INT_SYSTEM_CONFIG_MULT_VECTOR);
    INTEnableInterrupts     ();

    Rs485RxLineConfig();
    Rs485TxLineConfig();
    Rs485TxDisable();
    Rs485RxEnable();

    return TRUE ;
}

#define __UART_1_ISR    __ISR(_UART_1_VECTOR, ipl4)
void __UART_1_ISR  UART_1_InterruptRoutine(void)
{
    UART1Info_count++ ; 
    IFS0CLR = _IFS0_U1RXIF_MASK;
    UART1Info_LastByteRXed = UART1ReceivedValue();
    UART1TransmitTestASCIICharacters( (UART1Info_LastByteRXed+1), 1); //reflect back character, incremented by 1
}

Other information

• Processor: PIC32MX695F512L
• Compiler: C32 v2.00
• IDE: MPLAB X IDE

My question

How to I create a interrupt handler on receive BYTE via UART on PIC32 with C32 v2.00 compiler?

Note: Updated source code example with UART init()

Answer 1

Your example code doesn't show any of the initialization for the UART.

Are you enabling the receive interrupt for the UART? You need to do something like this:

#define BAUDRATE1       (115200)     // the desired BaudRate
#define BRATE1    (FPB/4/BAUDRATE1) 
#define UART1_CONFIG1   UART_EN|UART_BRGH_FOUR      // defaults to 8,N,1
#define UART1_CONFIG2   UART_RX_ENABLE|UART_TX_ENABLE|UART_INT_RX_CHAR              // only RX interrupts

void ConfigureUart1(void)
{
    OpenUART1(UART1_CONFIG1, UART1_CONFIG2, BRATE1); // approx 115200 baud
}

where FPB is defined as your peripheral bus frequency, e.g. 10000000L for 10 MHz.

Then in main or elsewhere:

ConfigureUart1();
INTEnableSystemMultiVectoredInt();         
INTEnableInterrupts();