tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC11U6X/serial_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 // math.h required for floating point operations for baud rate calculation
  18 #include "mbed_assert.h"
  19 #include <math.h>
  20 #include <string.h>
  21 #include <stdlib.h>
  22
  23 #include "serial_api.h"
  24 #include "cmsis.h"
  25 #include "pinmap.h"
  26
  27 #if DEVICE_SERIAL
  28
  29 /******************************************************************************
  30  * INITIALIZATION
  31  ******************************************************************************/
  32
  33 #define UART_NUM      5
  34
  35 // CFG
  36 #define UART_EN       (0x01<<0)
  37
  38 // CTL
  39 #define TXBRKEN       (0x01<<1)
  40
  41 // STAT
  42 #define RXRDY         (0x01<<0)
  43 #define TXRDY         (0x01<<2)
  44 #define DELTACTS      (0x01<<5)
  45 #define RXBRK         (0x01<<10)
  46 #define DELTARXBRK    (0x01<<11)
  47
  48 static const PinMap PinMap_UART_TX[] = {
  49     {P0_19, UART_0, 1},
  50     {P1_18, UART_0, 2},
  51     {P1_27, UART_0, 2},
  52     {P1_8 , UART_1, 2},
  53     {P1_0 , UART_2, 3},
  54     {P1_23, UART_2, 3},
  55     {P2_4 , UART_3, 1},
  56     {P2_12, UART_4, 1},
  57     { NC  , NC    , 0}
  58 };
  59
  60 static const PinMap PinMap_UART_RX[] = {
  61     {P0_18, UART_0, 1},
  62     {P1_17, UART_0, 2},
  63     {P1_26, UART_0, 2},
  64     {P1_2 , UART_1, 3},
  65     {P0_20, UART_2, 2},
  66     {P1_6 , UART_2, 2},
  67     {P2_3 , UART_3, 1},
  68     {P2_11, UART_4, 1},
  69     {NC   , NC    , 0}
  70 };
  71
  72 static uint32_t serial_irq_ids[UART_NUM] = {0};
  73 static uart_irq_handler irq_handler;
  74
  75 int stdio_uart_inited = 0;
  76 serial_t stdio_uart;
  77
  78 void serial_init(serial_t *obj, PinName tx, PinName rx) {
  79     int is_stdio_uart = 0;
  80
  81     // determine the UART to use
  82     UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX);
  83     UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX);
  84     UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx);
  85     MBED_ASSERT((int)uart != NC);
  86
  87     switch (uart) {
  88         case UART_0:
  89             obj->index = 0;
  90             LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 12);
  91             break;
  92         case UART_1:
  93             obj->index = 1;
  94             LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 20);
  95             LPC_SYSCON->PRESETCTRL |= (1 << 5);
  96             break;
  97         case UART_2:
  98             obj->index = 2;
  99             LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 21);
 100             LPC_SYSCON->PRESETCTRL |= (1 << 6);
 101             break;
 102         case UART_3:
 103             obj->index = 3;
 104             LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 22);
 105             LPC_SYSCON->PRESETCTRL |= (1 << 7);
 106             break;
 107         case UART_4:
 108             obj->index = 4;
 109             LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 22);
 110             LPC_SYSCON->PRESETCTRL |= (1 << 8);
 111             break;
 112     }
 113
 114     if (obj->index == 0)
 115         obj->uart = (LPC_USART0_Type *)uart;
 116     else
 117         obj->mini_uart = (LPC_USART4_Type *)uart;
 118
 119     if (obj->index == 0) {
 120         // enable fifos and default rx trigger level
 121         obj->uart->FCR = 1 << 0  // FIFO Enable - 0 = Disables, 1 = Enabled
 122                        | 0 << 1  // Rx Fifo Clear
 123                        | 0 << 2  // Tx Fifo Clear
 124                        | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars
 125         // disable irqs
 126         obj->uart->IER = 0 << 0  // Rx Data available irq enable
 127                        | 0 << 1  // Tx Fifo empty irq enable
 128                        | 0 << 2; // Rx Line Status irq enable
 129     }
 130     else {
 131         // Clear all status bits
 132         obj->mini_uart->STAT = (DELTACTS | DELTARXBRK);
 133         // Enable UART
 134         obj->mini_uart->CFG |= UART_EN;
 135     }
 136     // set default baud rate and format
 137     serial_baud  (obj, 9600);
 138     serial_format(obj, 8, ParityNone, 1);
 139
 140     // pinout the chosen uart
 141     pinmap_pinout(tx, PinMap_UART_TX);
 142     pinmap_pinout(rx, PinMap_UART_RX);
 143
 144     // set rx/tx pins in PullUp mode
 145     if (tx != NC) {
 146         pin_mode(tx, PullUp);
 147     }
 148     if (rx != NC) {
 149         pin_mode(rx, PullUp);
 150     }
 151
 152     is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
 153
 154     if (is_stdio_uart && (obj->index == 0)) {
 155         stdio_uart_inited = 1;
 156         memcpy(&stdio_uart, obj, sizeof(serial_t));
 157     }
 158 }
 159
 160 void serial_free(serial_t *obj) {
 161     serial_irq_ids[obj->index] = 0;
 162 }
 163
 164 // serial_baud
 165 // set the baud rate, taking in to account the current SystemFrequency
 166 void serial_baud(serial_t *obj, int baudrate) {
 167     LPC_SYSCON->USART0CLKDIV = 1;
 168     LPC_SYSCON->FRGCLKDIV = 1;
 169
 170     if (obj->index == 0) {
 171         uint32_t PCLK = SystemCoreClock;
 172         // First we check to see if the basic divide with no DivAddVal/MulVal
 173         // ratio gives us an integer result. If it does, we set DivAddVal = 0,
 174         // MulVal = 1. Otherwise, we search the valid ratio value range to find
 175         // the closest match. This could be more elegant, using search methods
 176         // and/or lookup tables, but the brute force method is not that much
 177         // slower, and is more maintainable.
 178         uint16_t DL = PCLK / (16 * baudrate);
 179
 180         uint8_t DivAddVal = 0;
 181         uint8_t MulVal = 1;
 182         int hit = 0;
 183         uint16_t dlv;
 184         uint8_t mv, dav;
 185         if ((PCLK % (16 * baudrate)) != 0) {     // Checking for zero remainder
 186             int err_best = baudrate, b;
 187             for (mv = 1; mv < 16 && !hit; mv++)
 188             {
 189                 for (dav = 0; dav < mv; dav++)
 190                 {
 191                     // baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
 192                     // solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
 193                     // mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
 194                     // for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
 195                     // note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
 196
 197                     if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
 198                         dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
 199                     else // 2 bits headroom, use more precision
 200                         dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
 201
 202                     // datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
 203                     if (dlv == 0)
 204                         dlv = 1;
 205
 206                     // datasheet says if dav > 0 then DL must be >= 2
 207                     if ((dav > 0) && (dlv < 2))
 208                         dlv = 2;
 209
 210                     // integer rearrangement of the baudrate equation (with rounding)
 211                     b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
 212
 213                     // check to see how we went
 214                     b = abs(b - baudrate);
 215                     if (b < err_best)
 216                     {
 217                         err_best  = b;
 218
 219                         DL        = dlv;
 220                         MulVal    = mv;
 221                         DivAddVal = dav;
 222
 223                         if (b == baudrate)
 224                         {
 225                             hit = 1;
 226                             break;
 227                         }
 228                     }
 229                 }
 230             }
 231         }
 232
 233         // set LCR[DLAB] to enable writing to divider registers
 234         obj->uart->LCR |= (1 << 7);
 235
 236         // set divider values
 237         obj->uart->DLM = (DL >> 8) & 0xFF;
 238         obj->uart->DLL = (DL >> 0) & 0xFF;
 239         obj->uart->FDR = (uint32_t) DivAddVal << 0
 240                        | (uint32_t) MulVal    << 4;
 241
 242         // clear LCR[DLAB]
 243         obj->uart->LCR &= ~(1 << 7);
 244     }
 245     else {
 246         uint32_t UARTSysClk = SystemCoreClock / LPC_SYSCON->FRGCLKDIV;
 247         obj->mini_uart->BRG = UARTSysClk / 16 / baudrate - 1;
 248
 249         LPC_SYSCON->UARTFRGDIV = 0xFF;
 250         LPC_SYSCON->UARTFRGMULT = ( ((UARTSysClk / 16) * (LPC_SYSCON->UARTFRGDIV + 1)) /
 251                                     (baudrate * (obj->mini_uart->BRG + 1))
 252                                   ) - (LPC_SYSCON->UARTFRGDIV + 1);
 253     }
 254 }
 255
 256 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
 257     MBED_ASSERT((stop_bits == 1) || (stop_bits == 2)); // 0: 1 stop bits, 1: 2 stop bits
 258
 259     stop_bits -= 1;
 260
 261     if (obj->index == 0) {
 262         MBED_ASSERT((data_bits > 4) && (data_bits < 9)); // 0: 5 data bits ... 3: 8 data bits
 263         MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven) ||
 264                     (parity == ParityForced1) || (parity == ParityForced0));
 265         data_bits -= 5;
 266
 267         int parity_enable, parity_select;
 268         switch (parity) {
 269             case ParityNone: parity_enable = 0; parity_select = 0; break;
 270             case ParityOdd : parity_enable = 1; parity_select = 0; break;
 271             case ParityEven: parity_enable = 1; parity_select = 1; break;
 272             case ParityForced1: parity_enable = 1; parity_select = 2; break;
 273             case ParityForced0: parity_enable = 1; parity_select = 3; break;
 274             default:
 275                 return;
 276         }
 277
 278         obj->uart->LCR = data_bits       << 0
 279                        | stop_bits       << 2
 280                        | parity_enable   << 3
 281                        | parity_select   << 4;
 282     }
 283     else {
 284         // 0: 7 data bits ... 2: 9 data bits
 285         MBED_ASSERT((data_bits > 6) && (data_bits < 10));
 286         MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven));
 287         data_bits -= 7;
 288
 289         int paritysel;
 290         switch (parity) {
 291             case ParityNone: paritysel = 0; break;
 292             case ParityEven: paritysel = 2; break;
 293             case ParityOdd : paritysel = 3; break;
 294             default:
 295                 return;
 296         }
 297         obj->mini_uart->CFG = (data_bits << 2)
 298                             | (paritysel << 4)
 299                             | (stop_bits << 6)
 300                             | UART_EN;
 301     }
 302 }
 303
 304 /******************************************************************************
 305  * INTERRUPTS HANDLING
 306  ******************************************************************************/
 307 static inline void uart_irq(uint32_t iir, uint32_t index) {
 308     SerialIrq irq_type;
 309     switch (iir) {
 310         case 1: irq_type = TxIrq; break;
 311         case 2: irq_type = RxIrq; break;
 312         default: return;
 313     }
 314
 315     if (serial_irq_ids[index] != 0)
 316         irq_handler(serial_irq_ids[index], irq_type);
 317 }
 318
 319 void uart0_irq()
 320 {
 321     uart_irq((LPC_USART0->IIR >> 1) & 0x7, 0);
 322 }
 323
 324 void uart1_irq()
 325 {
 326     uart_irq((LPC_USART1->STAT & (1 << 2)) ? 2 : 1, 1);
 327 }
 328
 329 void uart2_irq()
 330 {
 331     uart_irq((LPC_USART1->STAT & (1 << 2)) ? 2 : 1, 2);
 332 }
 333
 334 void uart3_irq()
 335 {
 336     uart_irq((LPC_USART1->STAT & (1 << 2)) ? 2 : 1, 3);
 337 }
 338
 339 void uart4_irq()
 340 {
 341     uart_irq((LPC_USART1->STAT & (1 << 2)) ? 2 : 1, 4);
 342 }
 343
 344 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
 345     irq_handler = handler;
 346     serial_irq_ids[obj->index] = id;
 347 }
 348
 349 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
 350     IRQn_Type irq_n = (IRQn_Type)0;
 351     uint32_t vector = 0;
 352     switch ((int)obj->uart) {
 353         case UART_0: irq_n = USART0_IRQn;   vector = (uint32_t)&uart0_irq; break;
 354         case UART_1: irq_n = USART1_4_IRQn; vector = (uint32_t)&uart1_irq; break;
 355         case UART_2: irq_n = USART2_3_IRQn; vector = (uint32_t)&uart2_irq; break;
 356         case UART_3: irq_n = USART2_3_IRQn; vector = (uint32_t)&uart3_irq; break;
 357         case UART_4: irq_n = USART1_4_IRQn; vector = (uint32_t)&uart4_irq; break;
 358     }
 359
 360     if (enable) {
 361         if (obj->index == 0) {
 362             obj->uart->IER |= (1 << irq);
 363         }
 364         else {
 365             obj->mini_uart->INTENSET = (1 << ((irq == RxIrq) ? 0 : 2));
 366         }
 367         NVIC_SetVector(irq_n, vector);
 368         NVIC_EnableIRQ(irq_n);
 369     } else { // disable
 370         int all_disabled = 0;
 371         SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
 372
 373         if (obj->index == 0) {
 374             obj->uart->IER &= ~(1 << irq);
 375             all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
 376         }
 377         else {
 378             obj->mini_uart->INTENSET &= ~(1 << ((irq == RxIrq) ? 0 : 2));
 379             all_disabled = (obj->mini_uart->INTENSET & (1 << ((other_irq == RxIrq) ? 0 : 2))) == 0;
 380          }
 381
 382         if (all_disabled)
 383             NVIC_DisableIRQ(irq_n);
 384     }
 385 }
 386
 387 /******************************************************************************
 388  * READ/WRITE
 389  ******************************************************************************/
 390 int serial_getc(serial_t *obj) {
 391     while (!serial_readable(obj));
 392     if (obj->index == 0) {
 393         return obj->uart->RBR;
 394     }
 395     else {
 396         return obj->mini_uart->RXDAT;
 397     }
 398 }
 399
 400 void serial_putc(serial_t *obj, int c) {
 401     while (!serial_writable(obj));
 402     if (obj->index == 0) {
 403         obj->uart->THR = c;
 404     }
 405     else {
 406         obj->mini_uart->TXDAT = c;
 407     }
 408 }
 409
 410 int serial_readable(serial_t *obj) {
 411     if (obj->index == 0) {
 412         return obj->uart->LSR & 0x01;
 413     }
 414     else {
 415         return obj->mini_uart->STAT & RXRDY;
 416     }
 417 }
 418
 419 int serial_writable(serial_t *obj) {
 420     if (obj->index == 0) {
 421         return obj->uart->LSR & 0x20;
 422     }
 423     else {
 424         return obj->mini_uart->STAT & TXRDY;
 425     }
 426 }
 427
 428 void serial_clear(serial_t *obj) {
 429     if (obj->index == 0) {
 430         obj->uart->FCR = 1 << 1  // rx FIFO reset
 431                        | 1 << 2  // tx FIFO reset
 432                        | 0 << 6; // interrupt depth
 433     }
 434     else {
 435         obj->mini_uart->STAT = 0;
 436     }
 437 }
 438
 439 void serial_pinout_tx(PinName tx) {
 440     pinmap_pinout(tx, PinMap_UART_TX);
 441 }
 442
 443 void serial_break_set(serial_t *obj) {
 444     if (obj->index == 0) {
 445         obj->uart->LCR |= (1 << 6);
 446     }
 447     else {
 448         obj->mini_uart->CTL |= TXBRKEN;
 449     }
 450 }
 451
 452 void serial_break_clear(serial_t *obj) {
 453     if (obj->index == 0) {
 454         obj->uart->LCR &= ~(1 << 6);
 455     }
 456     else {
 457         obj->mini_uart->CTL &= ~TXBRKEN;
 458     }
 459 }
 460
 461
 462 #endif