dsPic33E：没有DMA示例的UART不工作

时间：2016-07-21 12:45:05

标签： uart microchip mplab dspic

我使用的是dsPic33EP512GM604。我设计了一个测试电路来测试UART通信。

我从Microchip网站下载了sample code，并根据我的设备和电路进行了相应修改。

我在调试时遇到两个问题。

  1. PLL设置不起作用。每次它被困在“while（OSCCONbits.COSC！= 0b011）;”。因此，我评论了时钟配置和使用简单的内部振荡器FRC。

  2. UART通信无效。我在电路上使用 RPI25 作为 RX ，而 RP20 作为 TX 。 circuit Diagram

    3. 这是我正在使用的最终代码：

    /*******************************************************************************/
#include <xc.h>
#include <stdint.h>
#if __XC16_VERSION < 1011
#warning "Please upgrade to XC16 v1.11 or newer."
#endif
//-----------------------------------------------------------------------------
#pragma config ICS = PGD3 // ICD Communication Channel Select bits (Communicate on PGEC1 and PGED1)
#pragma config JTAGEN = OFF // JTAG Enable bit (JTAG is disabled)

// FPOR
#pragma config BOREN = ON // Brown-out Reset (BOR) Detection Enable bit (BOR is enabled)
#pragma config ALTI2C1 = OFF // Alternate I2C1 pins (I2C1 mapped to SDA1/SCL1 pins)
#pragma config ALTI2C2 = OFF // Alternate I2C2 pins (I2C2 mapped to SDA2/SCL2 pins)
#pragma config WDTWIN = WIN25 // Watchdog Window Select bits (WDT Window is 25% of WDT period)

// FWDT
#pragma config WDTPOST = PS32768 // Watchdog Timer Postscaler bits (1:32,768)
#pragma config WDTPRE = PR128 // Watchdog Timer Prescaler bit (1:128)
#pragma config PLLKEN = OFF // PLL Lock Enable bit (Clock switch to PLL source will wait until the PLL lock signal is valid.)
#pragma config WINDIS = OFF // Watchdog Timer Window Enable bit (Watchdog Timer in Non-Window mode)
#pragma config FWDTEN = OFF // Watchdog Timer Enable bit (Watchdog timer enabled/disabled by user software)

// FOSC
#pragma config POSCMD = NONE // Primary Oscillator Mode Select bits (XT Crystal Oscillator Mode)
#pragma config OSCIOFNC = OFF // OSC2 Pin Function bit (OSC2 is clock output)
#pragma config IOL1WAY = OFF // Peripheral pin select configuration (Allow multiple reconfigurations)
#pragma config FCKSM = CSDCMD // Clock Switching Mode bits (Clock switching is enabled,Fail-safe Clock Monitor is disabled)

// FOSCSEL
#pragma config FNOSC = FRC // Oscillator Source Selection (Internal Fast RC (FRC))
#pragma config PWMLOCK = ON // PWM Lock Enable bit (Certain PWM registers may only be written after key sequence)
#pragma config IESO = ON // Two-speed Oscillator Start-up Enable bit (Start up with user-selected oscillator source)

// FGS
#pragma config GWRP = OFF // General Segment Write-Protect bit (General Segment may be written)
#pragma config GCP = OFF // General Segment Code-Protect bit (General Segment Code protect is Disabled)

// *****************************************************************************
#define TRUE 1
#define FALSE 0
#define DELAY_105uS asm volatile ("REPEAT, #4201"); Nop();// 105uS delay
// *****************************************************************************
#define FCY 60000000
#define BAUDRATE 9600
#define BRGVAL ( (FCY / BAUDRATE) / 16 ) - 1
uint8_t s3flag, s4flag, s5flag, S6Flag;

/*****************************************************************************/
void __attribute__ ( (interrupt, no_auto_psv) ) _U1RXInterrupt( void )
{
    LATA = U1RXREG;
    U1TXREG = LATA;
    IFS0bits.U1RXIF = 0;
 }

/******************************************************************************/
 void __attribute__ ( (interrupt, no_auto_psv) ) _U1TXInterrupt( void )
{
    IFS0bits.U1TXIF = 0;
 }

/******************************************************************************/
void InitClock( void )
{
      PLLFBD = 58; // M = 60
      CLKDIVbits.PLLPOST = 0; // N1 = 2
      CLKDIVbits.PLLPRE = 0; // N2 = 2
      OSCTUN = 0;
      RCONbits.SWDTEN = 0;

       // Clock switch to incorporate PLL
      __builtin_write_OSCCONH( 0x03 ); // Initiate Clock Switch to

      // External oscillator with PLL (NOSC=0b011)
     __builtin_write_OSCCONL( OSCCON || 0x01 ); // Start clock switching
     while( OSCCONbits.COSC != 0b011 );

      // Wait for Clock switch to occur
      while( OSCCONbits.LOCK != 1 )
      { };
}

/******************************************************************************/
void InitUART2( void )
{
       // configure U1MODE
       U1MODEbits.UARTEN = 0; // Bit15 TX, RX DISABLED, ENABLE at end of func
      //U1MODEbits.notimplemented;// Bit14
      U1MODEbits.USIDL = 0; // Bit13 Continue in Idle
      U1MODEbits.IREN = 0; // Bit12 No IR translation
      U1MODEbits.RTSMD = 0; // Bit11 Simplex Mode
      //U1MODEbits.notimplemented;// Bit10
      U1MODEbits.UEN = 0; // Bits8,9 TX,RX enabled, CTS,RTS not
      U1MODEbits.WAKE = 0; // Bit7 No Wake up (since we don't sleep here)
      U1MODEbits.LPBACK = 0; // Bit6 No Loop Back
      U1MODEbits.ABAUD = 0; // Bit5 No Autobaud (would require sending '55')
      U1MODEbits.BRGH = 0; // Bit3 16 clocks per bit period
      U1MODEbits.PDSEL = 0; // Bits1,2 8bit, No Parity
      U1MODEbits.STSEL = 0; // Bit0 One Stop Bit

      U1BRG = BRGVAL; // 60Mhz osc, 9600 Baud
      // Load all values in for U1STA SFR
      U1STAbits.UTXISEL1 = 0; //Bit15 Int when Char is transferred (1/2 config!)
      U1STAbits.UTXINV = 0; //Bit14 N/A, IRDA config
      U1STAbits.UTXISEL0 = 0; //Bit13 Other half of Bit15
      //U1STAbits.notimplemented = 0;//Bit12
      U1STAbits.UTXBRK = 0; //Bit11 Disabled
      U1STAbits.UTXEN = 0; //Bit10 TX pins controlled by periph
      U1STAbits.UTXBF = 0; //Bit9 *Read Only Bit*
      U1STAbits.TRMT = 0; //Bit8 *Read Only bit*
      U1STAbits.URXISEL = 0; //Bits6,7 Int. on character recieved
      U1STAbits.ADDEN = 0; //Bit5 Address Detect Disabled
      U1STAbits.RIDLE = 0; //Bit4 *Read Only Bit*
      U1STAbits.PERR = 0; //Bit3 *Read Only Bit*
      U1STAbits.FERR = 0; //Bit2 *Read Only Bit*
      U1STAbits.OERR = 0; //Bit1 *Read Only Bit*
      U1STAbits.URXDA = 0; //Bit0 *Read Only Bit*
      IPC7 = 0x4400; // Mid Range Interrupt Priority level, no urgent reason
      IFS0bits.U1TXIF = 0; // Clear the Transmit Interrupt Flag
      IEC0bits.U1TXIE = 1; // Enable Transmit Interrupts
      IFS0bits.U1RXIF = 0; // Clear the Recieve Interrupt Flag
      IEC0bits.U1RXIE = 1; // Enable Recieve Interrupts

       // RPOR1bits.RP36R = 1; //RB4 as U1TX
      // RPINR18bits.U1RXR = 24; //RA8 as U1RX

      RPOR0bits.RP20R = 1; // dsPic33EP512GM604 => RP20 as U1TX
      _U1RXR = 19; // dsPic33EP512GM604 => RPI25 as U1RX

     U1MODEbits.UARTEN = 1; // And turn the peripheral on
     U1STAbits.UTXEN = 1;
}

/******************************************************************************/
void InitPorts( void )
{
      ANSELA = 0;

     // TRISAbits.TRISA9 = 1;
     // TRISAbits.TRISA4 = 0;

     TRISAbits.TRISA10 = 0; //Output
}

 /******************************************************************************
int main( void )
{
       char recChar = 'a';
       int i = 0;
       // int count = 0;
       // InitClock(); // This is the PLL settings
       InitUART2(); // Initialize UART2 for 9600,8,N,1 TX/RX
       InitPorts(); // LEDs outputs, Switches Inputs

        /* Wait at least 105 microseconds (1/9600) before sending first char */
       DELAY_105uS;

      while( 1 )
      {
            PORTAbits.RA10 = 0;
            for (i = 0; i < 1000; i++){
                     DELAY_105uS;
            }

            U1TXREG = recChar;
            recChar++;

            if (recChar == 122){
                    recChar = 48;
            }

           if (U1STAbits.OERR == 1){
                    U1STAbits.OERR = 0;
                    continue;
            }

            PORTAbits.RA10 = 0;
            for (i = 0; i < 1000; i++){
                     DELAY_105uS;
            }
      }
}
/*******************************************************************************

    我已经通过在RA10上添加LED及其工作来测试电路。所以，我猜我的代码可能有错误。

    得到了问题。现在它的工作

    编辑测试代码如下： 

    void InitClock( void )
{
    // Configure PLL prescaler, PLL postscaler, PLL divisor
    PLLFBD  =   63;                      // M=65
    CLKDIVbits.PLLPOST  =   0;           // N2=2
    CLKDIVbits.PLLPRE   =   0;           // N1=2

    // Initiate Clock Switch to FRC oscillator with PLL (NOSC=0b001)
    __builtin_write_OSCCONH(0x01);
    __builtin_write_OSCCONL(OSCCON | 0x01);

    // Wait for Clock switch to occur
    while (OSCCONbits.COSC!= 0b001);

    // Wait for PLL to lock
    while (OSCCONbits.LOCK!= 1);
}

void InitUART2( void )
{
     // configure U1MODE
     U1MODEbits.UARTEN = 0;  // Bit15 TX, RX DISABLED, ENABLE at end of func

     //U1MODEbits.notimplemented;// Bit10
     U1MODEbits.UEN = 0;     // Bits8,9 TX,RX enabled, CTS,RTS not

     U1MODEbits.ABAUD = 0;   // Bit5 No Autobaud (would require sending '55')
     U1MODEbits.BRGH = 0;    // Bit3 16 clocks per bit period
     U1MODEbits.PDSEL = 0;   // Bits1,2 8bit, No Parity
     U1MODEbits.STSEL = 0;   // Bit0 One Stop Bit

     // Load a value into Baud Rate Generator.
     U1BRG = BRGVAL;            // 60Mhz osc, 9600 Baud

     // Load all values in for U1STA SFR
     U1STAbits.UTXISEL1 = 0; //Bit15 Int when Char is transferred (1/2 config!)
     U1STAbits.UTXISEL0 = 0; //Bit13 Other half of Bit15

     U1STAbits.UTXBRK = 0;   //Bit11 Disabled
     U1STAbits.UTXEN = 0;    //Bit10 TX pins controlled by periph
     U1STAbits.URXISEL = 0;  //Bits6,7 Int. on character recieved
     IPC7 = 0x4400;          // Mid Range Interrupt Priority level, no urgent reason
     IFS0bits.U1TXIF = 0;    // Clear the Transmit Interrupt Flag
     IEC0bits.U1TXIE = 1;    // Enable Transmit Interrupts
     IFS0bits.U1RXIF = 0;    // Clear the Recieve Interrupt Flag
     IEC0bits.U1RXIE = 1;    // Enable Recieve Interrupts

     RPOR0bits.RP20R = 1;    // dsPic33EP512GM604 => RP20 as U1TX
     _U1RXR = 0x19;            // dsPic33EP512GM604 => RPI25 as U1RX

     U1MODEbits.UARTEN = 1;  // And turn the peripheral on
     U1STAbits.UTXEN = 1;
}

    应用这些更改使我的代码正常工作。

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