src/part2/examples/local/runtime/SysUart.c

/*
 *  ======== SysUart.c ========
 */
#include <xdc/runtime/Startup.h>

#include "package/internal/SysUart.xdc.h"

#define USE_8MHZ    1

#define RED         0x01
#define GREEN       0x02

#define FOREVER     -1

static void etx();
static void flash(Int color, Int period, Int count);
static void init(void);
static void myPutc(Char ch);

/*
 *  ======== SysUart_Module_startup ========
 */
Int SysUart_Module_startup(Int state)
{
    init();    
    return (Startup_DONE);
}

/*
 *  ======== SysUart_abort ========
 */
Void SysUart_abort(String str)
{
    if (str != NULL) {
        Char ch;
        
        while ((ch = *str++) != '\0') {
            SysUart_putch(ch);
        }
    }
    flash(RED, FOREVER, FOREVER);
    etx();
}

/*
 *  ======== SysUart_exit ========
 */
Void SysUart_exit(Int stat)
{
    flash(GREEN, FOREVER, FOREVER);
    etx();
}

/*
 *  ======== SysUart_flush ========
 */
Void SysUart_flush()
{
}

/*
 *  ======== SysUart_putch ========
 */
Void SysUart_putch(Char ch)
{
    myPutc(ch);
}

/*
 *  ======== SysUart_ready ========
 */
Bool SysUart_ready()
{
    return (TRUE);
}

/*
 *  ======== atexit ========
 *  The TI RTS library's atexit() implementation requires a _huge_ amount of
 *  data.  We stub it out here and replace exit() and abort() with functions
 *  that are sufficient for the proper operation of xdc.runtime.System.
 */
int atexit(void (*fxn)(void))
{
    return (0);
}

/*
 *  ======== abort ========
 *  See atexit() above
 */
void abort(void)
{
   /*  Define C$$EXIT label because TI debugger uses this to know when
    *  programs terminate.  This can be removed if the debugger is not
    *  used.
    */
   __asm("        .global C$$EXIT");
   __asm("C$$EXIT: nop");

   for (;;);   /* spin forever */
}

/*
 *  ======== exit ========
 *  See atexit() above
 */
void exit(int status)
{
    SysUart_exit(status);
}

/*
 *  ======== etx ========
 *  Flush HW TX buffers
 */
static void etx()
{
    myPutc(4);  /* ascii EOT */
    myPutc(0);
    myPutc(0);
    abort();
}
 
#if 0
/* standard header assumes linker command file definitions */
#include  <ti/apps/msp430/msp430x22x4.h>
#else                                     
/* "pure-C" definitions below are sufficient for this module */
#define IE2        (*(volatile int8_t *)0x0001)   /* 8-bit */
#define IFG2       (*(volatile int8_t *)0x0003)   /* 8-bit */

#define DCOCTL     (*(volatile int8_t *)0x0056)   /* 8-bit */
#define BCSCTL1    (*(volatile int8_t *)0x0057)   /* 8-bit */
#define BCSCTL3    (*(volatile int8_t *)0x0053)   /* 8-bit */

#define CALDCO_8MHZ (*(volatile int8_t *)0x10FC)  /* 8-bit */
#define CALBC1_8MHZ (*(volatile int8_t *)0x10FD)  /* 8-bit */

#define P1OUT      (*(volatile int8_t *)0x0021)   /* 8-bit */
#define P1DIR      (*(volatile int8_t *)0x0022)   /* 8-bit */
#define P3SEL      (*(volatile int8_t *)0x001B)   /* 8-bit */

#define UCA0CTL1   (*(volatile int8_t *)0x0061)   /* 8-bit */
#define UCA0BR0    (*(volatile int8_t *)0x0062)   /* 8-bit */
#define UCA0BR1    (*(volatile int8_t *)0x0063)   /* 8-bit */
#define UCA0MCTL   (*(volatile int8_t *)0x0064)   /* 8-bit */
#define UCA0RXBUF  (*(volatile int8_t *)0x0066)   /* 8-bit */
#define UCA0TXBUF  (*(volatile int8_t *)0x0067)   /* 8-bit */

#define WDTCTL     (*(volatile int16_t *)0x120)   /* 16-bit */

/* status register bits */
#define GIE        (0x0008)
#define CPUOFF     (0x0010)

#define LPM0_bits  (CPUOFF)

/* watch dog timer control register bit names */
#define WDTPW       (0x5A00)
#define WDTHOLD     (0x0080)

#define LFXT1S_2    (0x20)      /* Mode 2 for LFXT1 : VLO */

#define UCSSEL_2    (0x80)      /* USCI 0 Clock Source: 2 */
#define UCBRS_2      (0x04)      /* USCI Second Stage Modulation Select 1 */
#define UCSWRST     (0x01)      /* USCI Software Reset */
#define UCA0RXIE    (0x01)      /* USCI rx interrupt enable */

/* IFG2 bits */
#define UCA0TXIFG   (0x02)      /* USCI tx flag bit */
#endif

/*
 *  ======== init ========
 */
static void init(void)
{
    WDTCTL = WDTPW + WDTHOLD;       /* Stop watchdog timer */

    P1DIR |= 0x03;                  /* Set P1.0,1 to output direction */
    P1OUT = 0;                      /* turn off LEDs */

#if USE_8MHZ
    BCSCTL1 = CALBC1_8MHZ;          /* Set DCO to the default of Simpliciti */
    DCOCTL = CALDCO_8MHZ;
    BCSCTL3 |= LFXT1S_2;            /* LFXT1 = VLO */
#else
    BCSCTL1 = CALBC1_1MHZ;          /* Set DCO to 1MHz */
    DCOCTL = CALDCO_1MHZ;
#endif

    /* init the UART (see Table 15-4, Section 15.3.13 MSP430 User's guide) */
    P3SEL = 0x30;           /* P3.4,5 = USCI_A0 TXD/RXD */
    UCA0CTL1 = UCSSEL_2;    /* SMCLK */
#if USE_8MHZ
    UCA0BR0 = 0x41;         /* 8MHz DCO 9600 (UCBRx = 833) */
    UCA0BR1 = 0x03;         /* 8MHz DC0 9600 */
    UCA0MCTL = UCBRS_2;     /* 8MHz DC0 Modulation (UCBRSx = 2: UCOS16 = 0, UCBRFx = 0) */
#else
    UCA0BR0 = 104;          /* 1MHz DC0 9600 (@8MHz 9600, use 0x41) */
    UCA0BR1 = 0;            /* 1MHz DC0 9600 (@8MHz 9600, use 0x03) */
    UCA0MCTL = UCBRS0;      /* 1MHz DC0 Modulation (UCBRSx = 1: UCOS16 = 0, UCBRFx = 0) */
#endif

    UCA0CTL1 &= ~UCSWRST;   /* Initialize USCI state machine */
    IE2 |= UCA0RXIE;        /* Enable USCI_A0 RX interrupt */

    flash(GREEN, 50, 4);    /* indicate the init is done */
}

/*
 *  ======== flash ========
 */
static void flash(Int color, Int period, Int count)
{
    if (period == FOREVER) {
        P1OUT |= color;
        return;
    }
 
    while (count) {
        volatile unsigned int i;    /* volatile to prevent optimization */
        
        P1OUT ^= color;             /* toggle P1.1,0 using exclusive-OR */
        
        for (i = period * 1000; i != 0; i--) {  /* delay period */
            ;
        }

        if (count > 0) {            /* if count starts < 0, go forever */
            count--;
        }
    }
}

/*
 *  ======== myPutc ========
 */
static void myPutc(Char ch)
{
    while (!(IFG2 & UCA0TXIFG)) {   /* USCI_A0 TX buffer ready? */
        ;
    }

    UCA0TXBUF = ch;                 /* TX -> ch */
}

/*
 *  ======== USCI0RX_ISR ========
 */
__interrupt void USCI0RX_ISR(void)
{
    char c;
        
    c = UCA0RXBUF;                  /* read the character */

    if (SysUart_getLineFxn == NULL) {
        return;
    }

    if (SysUart_lineBuf == NULL) {
        SysUart_getLineFxn(&c, 1);
        return;
    }

    if (c == '\n') {
        SysUart_lineBuf[module->lineIdx] = 0;
        SysUart_getLineFxn(SysUart_lineBuf, module->lineIdx);
        module->lineIdx = 0;
    }
    else if (module->lineIdx < SysUart_lineSize) {
        SysUart_lineBuf[module->lineIdx++] = c;
    }
}

__asm("\t.global USCI0RX_ISR");
__asm("\t.sect   \".usci_rx\"");
__asm("\t.align  2");
__asm("_USCI0_rx_vector:\n\t.field USCI0RX_ISR, 16");