uart0x.c

00001 /*
00002  * Copyright (c) 2010, Swedish Institute of Computer Science
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the Institute nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  *
00029  * @(#)$Id: uart0x.c,v 1.1 2010/08/24 16:23:20 joxe Exp $
00030  */
00031 
00032 /*
00033  * Machine dependent MSP430X UART0 code.
00034  */
00035 
00036 #include <stdlib.h>
00037 #include <signal.h>
00038 
00039 #include "sys/energest.h"
00040 #include "dev/uart0.h"
00041 #include "dev/watchdog.h"
00042 #include "lib/ringbuf.h"
00043 #include "dev/leds.h"
00044 
00045 static int (*uart0_input_handler)(unsigned char c);
00046 
00047 static volatile uint8_t transmitting;
00048 
00049 #ifdef UART0_CONF_TX_WITH_INTERRUPT
00050 #define TX_WITH_INTERRUPT UART0_CONF_TX_WITH_INTERRUPT
00051 #else /* UART0_CONF_TX_WITH_INTERRUPT */
00052 #define TX_WITH_INTERRUPT 1
00053 #endif /* UART0_CONF_TX_WITH_INTERRUPT */
00054 
00055 
00056 #if TX_WITH_INTERRUPT
00057 #define TXBUFSIZE 64
00058 
00059 static struct ringbuf txbuf;
00060 static uint8_t txbuf_data[TXBUFSIZE];
00061 #endif /* TX_WITH_INTERRUPT */
00062 
00063 /*---------------------------------------------------------------------------*/
00064 uint8_t
00065 uart0_active(void)
00066 {
00067   return (UCA0STAT & UCBUSY) | transmitting;
00068 }
00069 /*---------------------------------------------------------------------------*/
00070 void
00071 uart0_set_input(int (*input)(unsigned char c))
00072 {
00073   uart0_input_handler = input;
00074 }
00075 /*---------------------------------------------------------------------------*/
00076 void
00077 uart0_writeb(unsigned char c)
00078 {
00079   watchdog_periodic();
00080 #if TX_WITH_INTERRUPT
00081   /* Put the outgoing byte on the transmission buffer. If the buffer
00082      is full, we just keep on trying to put the byte into the buffer
00083      until it is possible to put it there. */
00084   while(ringbuf_put(&txbuf, c) == 0);
00085 
00086   /* If there is no transmission going, we need to start it by putting
00087      the first byte into the UART. */
00088   if(transmitting == 0) {
00089     transmitting = 1;
00090     UCA0TXBUF = ringbuf_get(&txbuf);
00091   }
00092 
00093 #else /* TX_WITH_INTERRUPT */
00094 
00095   /* Loop until the transmission buffer is available. */
00096   /*Enric while((IFG2 & UCA0TXIFG) == 0); */
00097   while((UCA0STAT & UCBUSY));
00098 
00099   /* Transmit the data. */
00100   UCA0TXBUF = c;
00101 #endif /* TX_WITH_INTERRUPT */
00102 }
00103 /*---------------------------------------------------------------------------*/
00104 #if ! WITH_UIP /* If WITH_UIP is defined, putchar() is defined by the SLIP driver */
00105 #endif /* ! WITH_UIP */
00106 /*---------------------------------------------------------------------------*/
00107 /**
00108  * Initalize the RS232 port.
00109  *
00110  */
00111 void
00112 uart0_init(unsigned long ubr)
00113 {
00114   /* RS232 */
00115   UCA0CTL1 |= UCSWRST;            /* Hold peripheral in reset state */
00116   UCA0CTL1 |= UCSSEL_2;           /* CLK = SMCLK */
00117 
00118   UCA0BR0 = 0x45;                 /* 8MHz/115200 = 69 = 0x45 */
00119   UCA0BR1 = 0x00;
00120   UCA0MCTL = UCBRS_3;             /* Modulation UCBRSx = 3 */
00121 
00122   P3DIR &= ~0x20;                 /* P3.5 = USCI_A0 RXD as input */
00123   P3DIR |= 0x10;                  /* P3.4 = USCI_A0 TXD as output */
00124   P3SEL |= 0x30;                  /* P3.4,5 = USCI_A0 TXD/RXD */
00125   /*UCA0CTL1 &= ~UCSWRST;*/       /* Initialize USCI state machine */
00126 
00127   transmitting = 0;
00128 
00129   /* XXX Clear pending interrupts before enable */
00130   IFG2 &= ~UCA0RXIFG;
00131   IFG2 &= ~UCA0TXIFG;
00132   UCA0CTL1 &= ~UCSWRST;                   /* Initialize USCI state machine **before** enabling interrupts */
00133   IE2 |= UCA0RXIE;                        /* Enable UCA0 RX interrupt */
00134   /* Enable USCI_A0 TX interrupts (if TX_WITH_INTERRUPT enabled) */
00135 #if TX_WITH_INTERRUPT
00136   ringbuf_init(&txbuf, txbuf_data, sizeof(txbuf_data));
00137   IE2 |= UCA0TXIE;                        /* Enable UCA0 TX interrupt */
00138 #endif /* TX_WITH_INTERRUPT */
00139 }
00140 /*---------------------------------------------------------------------------*/
00141 interrupt(USCIAB0RX_VECTOR)
00142 uart0_rx_interrupt(void)
00143 {
00144   uint8_t c;
00145 
00146   ENERGEST_ON(ENERGEST_TYPE_IRQ);
00147   leds_toggle(LEDS_RED);
00148   if(UCA0STAT & UCRXERR) {
00149     c = UCA0RXBUF;   /* Clear error flags by forcing a dummy read. */
00150   } else {
00151     c = UCA0RXBUF;
00152     if(uart0_input_handler != NULL) {
00153       if(uart0_input_handler(c)) {
00154         LPM4_EXIT;
00155       }
00156     }
00157   }
00158   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
00159 }
00160 /*---------------------------------------------------------------------------*/
00161 #if TX_WITH_INTERRUPT
00162 interrupt(USCIAB0TX_VECTOR)
00163 uart0_tx_interrupt(void)
00164 {
00165   ENERGEST_ON(ENERGEST_TYPE_IRQ);
00166   if((IFG2 & UCA0TXIFG)){
00167     
00168     if(ringbuf_elements(&txbuf) == 0) {
00169       transmitting = 0;
00170     } else {
00171       UCA0TXBUF = ringbuf_get(&txbuf);
00172     }
00173   }
00174   
00175   /* In a stand-alone app won't work without this. Is the UG misleading? */
00176   IFG2 &= ~UCA0TXIFG;
00177 
00178   ENERGEST_OFF(ENERGEST_TYPE_IRQ);
00179 }
00180 #endif /* TX_WITH_INTERRUPT */
00181 /*---------------------------------------------------------------------------*/

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