adamdunkels | 573bc29 | 2003-10-01 08:04:03 +0000 | [diff] [blame] | 1 | /** |
| 2 | * \file |
| 3 | * RS232 communication device driver for the MSP430. |
| 4 | * \author Adam Dunkels <adam@sics.se> |
| 5 | * |
| 6 | * This file contains an RS232 device driver for the MSP430 microcontroller. |
| 7 | * |
| 8 | */ |
| 9 | |
| 10 | #include <io.h> |
| 11 | #include <signal.h> |
| 12 | |
| 13 | #include "rs232.h" |
| 14 | |
| 15 | void beep(void); |
| 16 | void blink(void); |
| 17 | |
| 18 | unsigned char lastchar, lastchar_changed; |
| 19 | |
| 20 | #define RECVBUF_SIZE 256 |
| 21 | |
| 22 | static unsigned char recvbuf[RECVBUF_SIZE]; |
| 23 | static unsigned char recvbufptr1 = 0, |
| 24 | recvbufptr2 = 0; |
| 25 | |
| 26 | interrupt(UART1RX_VECTOR) rs232_rx_usart1(void) |
| 27 | { |
| 28 | volatile unsigned char dummy; |
| 29 | |
| 30 | /* Check status register for receive errors. */ |
| 31 | if(URCTL1 & RXERR) { |
| 32 | /* Clear error flags by forcing a dummy read. */ |
| 33 | dummy = RXBUF1; |
| 34 | } else { |
| 35 | recvbuf[recvbufptr1] = RXBUF1; |
| 36 | recvbufptr1 = (recvbufptr1 + 1) % RECVBUF_SIZE; |
| 37 | } |
| 38 | } |
| 39 | /*-----------------------------------------------------------------------------------*/ |
| 40 | /** |
| 41 | * Initalize the RS232 port. |
| 42 | * |
| 43 | * \param none Not used. |
| 44 | * \return An error value or RS_ERR_OK if initialization succeeded. |
| 45 | */ |
| 46 | /*-----------------------------------------------------------------------------------*/ |
| 47 | unsigned char |
| 48 | rs232_init(char none) |
| 49 | { |
| 50 | int j; |
| 51 | |
| 52 | |
| 53 | /* This code taken from the FU Berlin sources and reformatted. */ |
| 54 | |
| 55 | #define DELTA 600 |
| 56 | |
| 57 | unsigned int compare, oldcapture = 0; |
| 58 | unsigned int i; |
| 59 | |
| 60 | BCSCTL1 = 0xa4; /* ACLK is devided by 4. RSEL=6 no division for MCLK |
| 61 | and SSMCLK. XT2 is off. */ |
| 62 | |
| 63 | BCSCTL2 = 0x00; /* Init FLL to desired frequency using the 32762Hz |
| 64 | crystal DCO frquenzy = 2,4576 MHz */ |
| 65 | |
| 66 | WDTCTL = WDTPW + WDTHOLD; /* Stop WDT */ |
| 67 | BCSCTL1 |= DIVA1 + DIVA0; /* ACLK = LFXT1CLK/8 */ |
| 68 | for(i = 0xffff; i > 0; --i); /* Delay for XTAL to settle */ |
| 69 | |
| 70 | /* Set DCO for 2,4576 Mhz: */ |
| 71 | CCTL2 = CCIS0 + CM0 + CAP; /* Define CCR2, CAP, ACLK */ |
| 72 | TACTL = TASSEL1 + TACLR + MC1; /* SMCLK, continous mode */ |
| 73 | while(1) { |
| 74 | while((CCTL2 & CCIFG) != CCIFG); /* Wait until capture occured! */ |
| 75 | CCTL2 &= ~CCIFG; /* Capture occured, clear flag */ |
| 76 | compare = CCR2; /* Get current captured SMCLK */ |
| 77 | compare = compare - oldcapture; /* SMCLK difference */ |
| 78 | oldcapture = CCR2; /* Save current captured SMCLK */ |
| 79 | |
| 80 | if(DELTA == compare) { |
| 81 | break; /* if equal, leave "while(1)" */ |
| 82 | } else if(DELTA < compare) { /* DCO is too fast, slow it down */ |
| 83 | DCOCTL--; |
| 84 | if(DCOCTL == 0xFF) { /* Did DCO role under? */ |
| 85 | BCSCTL1--; |
| 86 | } |
| 87 | } else { /* -> Select next lower RSEL */ |
| 88 | DCOCTL++; |
| 89 | if(DCOCTL == 0x00) { /* Did DCO role over? */ |
| 90 | BCSCTL1++; |
| 91 | } |
| 92 | /* -> Select next higher RSEL */ |
| 93 | } |
| 94 | } |
| 95 | CCTL2 = 0; /* Stop CCR2 function */ |
| 96 | TACTL = 0; /* Stop Timer_A */ |
| 97 | |
| 98 | |
| 99 | |
| 100 | /* RS232 */ |
| 101 | UCTL1 = CHAR; /* 8-bit character */ |
| 102 | UTCTL1 = SSEL1; /* UCLK = MCLK */ |
| 103 | |
| 104 | #define RS232_SPEED 57600 |
| 105 | |
| 106 | if(RS232_SPEED == 19200) { |
| 107 | /* Set RS232 to 19200 */ |
| 108 | UBR01 = 0x80; /* 2,457MHz/19200 = 128 -> 0x80 */ |
| 109 | UBR11 = 0x00; /* */ |
| 110 | UMCTL1 = 0x00; /* no modulation */ |
| 111 | } else if(RS232_SPEED == 38400) { |
| 112 | /* Set RS232 to 38400 */ |
| 113 | UBR01 = 0x40; /* 2,457MHz/38400 = 64 -> 0x40 */ |
| 114 | UBR11 = 0x00; /* */ |
| 115 | UMCTL1 = 0x00; /* no modulation */ |
| 116 | } else if(RS232_SPEED == 57600) { |
| 117 | UBR01 = 0x2a; /* 2,457MHz/57600 = 42.7 -> 0x2A */ |
| 118 | UBR11 = 0x00; /* */ |
| 119 | UMCTL1 = 0x5b; /* */ |
| 120 | } else if(RS232_SPEED == 115200) { |
| 121 | UBR01 = 0x15; /* 2,457MHz/115200 = 21.4 -> 0x15 */ |
| 122 | UBR11 = 0x00; /* */ |
| 123 | UMCTL1 = 0x4a; /* */ |
| 124 | } |
| 125 | |
| 126 | |
| 127 | ME2 |= (UTXE1 | URXE1); /* Enable USART1 TXD/RXD */ |
| 128 | IE2 |= URXIE1; /* Enable USART1 RX interrupt */ |
| 129 | BCSCTL1 &= ~(DIVA1 + DIVA0); /* remove /8 divisor from ACLK again */ |
| 130 | |
| 131 | |
| 132 | return RS_ERR_OK; |
| 133 | } |
| 134 | /*-----------------------------------------------------------------------------------*/ |
| 135 | /** |
| 136 | * Configure the RS232 port. |
| 137 | * |
| 138 | * \param params RS232 parameters. |
| 139 | * \param parity Parity. |
| 140 | * \return An error value or RS_ERR_OK if configuration succeeded. |
| 141 | */ |
| 142 | /*-----------------------------------------------------------------------------------*/ |
| 143 | unsigned char |
| 144 | rs232_params(unsigned char params, unsigned char parity) |
| 145 | { |
| 146 | return RS_ERR_OK; |
| 147 | } |
| 148 | /*-----------------------------------------------------------------------------------*/ |
| 149 | /** |
| 150 | * Get a byte from the serial port. |
| 151 | * |
| 152 | * \param c A pointer to the location where the byte is to be stored. |
| 153 | * |
| 154 | * \return An error value or RS_ERR_OK. If no data is available, the |
| 155 | * function returns RS_ERR_NO_DATA which is not a fatal error. |
| 156 | */ |
| 157 | /*-----------------------------------------------------------------------------------*/ |
| 158 | unsigned char |
| 159 | rs232_get(char *c) |
| 160 | { |
| 161 | if(recvbufptr1 == recvbufptr2) { |
| 162 | return RS_ERR_NO_DATA; |
| 163 | } |
| 164 | *c = recvbuf[recvbufptr2]; |
| 165 | recvbufptr2 = (recvbufptr2 + 1) % RECVBUF_SIZE; |
| 166 | return RS_ERR_OK; |
| 167 | } |
| 168 | /*-----------------------------------------------------------------------------------*/ |
| 169 | /** |
| 170 | * Transmit a byte over the serial port. |
| 171 | * |
| 172 | * \param c A pointer to the location where the byte is to be stored. |
| 173 | * |
| 174 | * \return An error value or RS_ERR_OK. If the transmission buffer was |
| 175 | * full, RS_ERR_OVERFLOW is returned. |
| 176 | */ |
| 177 | /*-----------------------------------------------------------------------------------*/ |
| 178 | unsigned char |
| 179 | rs232_put(char c) |
| 180 | { |
| 181 | /* Loop until the transmission buffer is available. */ |
| 182 | while ((IFG2 & UTXIFG1) == 0); |
| 183 | |
| 184 | /* Transmit the data. */ |
| 185 | TXBUF1 = c; |
| 186 | |
| 187 | return RS_ERR_OK; |
| 188 | } |
| 189 | /*-----------------------------------------------------------------------------------*/ |