tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC43XX/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  * Ported to NXP LPC43XX by Micromint USA <support@micromint.com>
  17  */
  18 // math.h required for floating point operations for baud rate calculation
  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 #include "mbed_error.h"
  27 #include "gpio_api.h"
  28
  29 /******************************************************************************
  30  * INITIALIZATION
  31  ******************************************************************************/
  32 #define UART_NUM    4
  33
  34 // SCU mode for UART pins
  35 #define SCU_PINIO_UART_TX   SCU_MODE_PULLDOWN
  36 #define SCU_PINIO_UART_RX   SCU_PINIO_PULLNONE
  37
  38 static const PinMap PinMap_UART_TX[] = {
  39     {P1_13, UART_1, (SCU_PINIO_UART_TX | 1)},
  40     {P1_15, UART_2, (SCU_PINIO_UART_TX | 1)},
  41     {P2_0,  UART_0, (SCU_PINIO_UART_TX | 1)},
  42     {P2_3,  UART_3, (SCU_PINIO_UART_TX | 2)},
  43     {P2_10, UART_2, (SCU_PINIO_UART_TX | 2)},
  44     {P3_4,  UART_1, (SCU_PINIO_UART_TX | 4)},
  45     {P4_1,  UART_3, (SCU_PINIO_UART_TX | 6)},
  46     {P5_6,  UART_1, (SCU_PINIO_UART_TX | 4)},
  47     {P6_4,  UART_0, (SCU_PINIO_UART_TX | 2)},
  48     {P7_1,  UART_2, (SCU_PINIO_UART_TX | 6)},
  49     {P9_3,  UART_3, (SCU_PINIO_UART_TX | 7)},
  50     {P9_5,  UART_0, (SCU_PINIO_UART_TX | 7)},
  51     {PA_1,  UART_2, (SCU_PINIO_UART_TX | 3)},
  52     {PC_13, UART_1, (SCU_PINIO_UART_TX | 2)},
  53     {PE_11, UART_1, (SCU_PINIO_UART_TX | 2)},
  54     {PF_2,  UART_3, (SCU_PINIO_UART_TX | 1)},
  55     {PF_10, UART_0, (SCU_PINIO_UART_TX | 1)},
  56     {NC,    NC,     0}
  57 };
  58
  59 static const PinMap PinMap_UART_RX[] = {
  60     {P1_14, UART_1, (SCU_PINIO_UART_RX | 1)},
  61     {P1_16, UART_2, (SCU_PINIO_UART_RX | 1)},
  62     {P2_1,  UART_0, (SCU_PINIO_UART_RX | 1)},
  63     {P2_4,  UART_3, (SCU_PINIO_UART_RX | 2)},
  64     {P2_11, UART_2, (SCU_PINIO_UART_RX | 2)},
  65     {P3_5,  UART_1, (SCU_PINIO_UART_RX | 4)},
  66     {P4_2,  UART_3, (SCU_PINIO_UART_RX | 6)},
  67     {P5_7,  UART_1, (SCU_PINIO_UART_RX | 4)},
  68     {P6_5,  UART_0, (SCU_PINIO_UART_RX | 2)},
  69     {P7_2,  UART_2, (SCU_PINIO_UART_RX | 6)},
  70     {P9_4,  UART_3, (SCU_PINIO_UART_RX | 7)},
  71     {P9_6,  UART_0, (SCU_PINIO_UART_RX | 7)},
  72     {PA_2,  UART_2, (SCU_PINIO_UART_RX | 3)},
  73     {PC_14, UART_1, (SCU_PINIO_UART_RX | 2)},
  74     {PE_12, UART_1, (SCU_PINIO_UART_RX | 2)},
  75     {PF_3,  UART_3, (SCU_PINIO_UART_RX | 1)},
  76     {PF_11, UART_0, (SCU_PINIO_UART_RX | 1)},
  77     {NC,    NC,     0}
  78 };
  79
  80 #if (DEVICE_SERIAL_FC)
  81 // RTS/CTS PinMap for flow control
  82 static const PinMap PinMap_UART_RTS[] = {
  83     {P1_9,  UART_1, (SCU_PINIO_FAST | 1)},
  84     {P5_2,  UART_1, (SCU_PINIO_FAST | 4)},
  85     {PC_3,  UART_1, (SCU_PINIO_FAST | 2)},
  86     {PE_5,  UART_1, (SCU_PINIO_FAST | 2)},
  87     {NC,    NC,     0}
  88 };
  89
  90 static const PinMap PinMap_UART_CTS[] = {
  91     {P1_11, UART_1, (SCU_PINIO_FAST | 1)},
  92     {P5_4,  UART_1, (SCU_PINIO_FAST | 4),
  93     {PC_2,  UART_1, (SCU_PINIO_FAST | 2)},
  94     {PE_7,  UART_1, (SCU_PINIO_FAST | 2)},
  95     {NC,    NC,     0}
  96 };
  97 #endif
  98
  99 static uart_irq_handler irq_handler;
 100
 101 int stdio_uart_inited = 0;
 102 serial_t stdio_uart;
 103
 104 struct serial_global_data_s {
 105     uint32_t serial_irq_id;
 106     gpio_t sw_rts, sw_cts;
 107     uint8_t count, rx_irq_set_flow, rx_irq_set_api;
 108 };
 109
 110 static struct serial_global_data_s uart_data[UART_NUM];
 111
 112 void serial_init(serial_t *obj, PinName tx, PinName rx) {
 113     int is_stdio_uart = 0;
 114
 115     // determine the UART to use
 116     UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX);
 117     UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX);
 118     UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx);
 119     if ((int)uart == NC) {
 120         error("Serial pinout mapping failed");
 121     }
 122
 123     obj->uart = (LPC_USART_T *)uart;
 124
 125     // enable fifos and default rx trigger level
 126     obj->uart->FCR = 1 << 0  // FIFO Enable - 0 = Disables, 1 = Enabled
 127                    | 0 << 1  // Rx Fifo Reset
 128                    | 0 << 2  // Tx Fifo Reset
 129                    | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars
 130
 131     // disable irqs
 132     obj->uart->IER = 0 << 0  // Rx Data available irq enable
 133                    | 0 << 1  // Tx Fifo empty irq enable
 134                    | 0 << 2; // Rx Line Status irq enable
 135
 136     // set default baud rate and format
 137     is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
 138     serial_baud  (obj, is_stdio_uart ? 115200 : 9600);
 139     serial_format(obj, 8, ParityNone, 1);
 140
 141     // pinout the chosen uart
 142     pinmap_pinout(tx, PinMap_UART_TX);
 143     pinmap_pinout(rx, PinMap_UART_RX);
 144
 145     // set rx/tx pins in PullUp mode
 146     if (tx != NC) {
 147         pin_mode(tx, PullUp);
 148     }
 149     if (rx != NC) {
 150         pin_mode(rx, PullUp);
 151     }
 152
 153     switch (uart) {
 154         case UART_0: obj->index = 0; break;
 155         case UART_1: obj->index = 1; break;
 156         case UART_2: obj->index = 2; break;
 157         case UART_3: obj->index = 3; break;
 158     }
 159     uart_data[obj->index].sw_rts.pin = NC;
 160     uart_data[obj->index].sw_cts.pin = NC;
 161     serial_set_flow_control(obj, FlowControlNone, NC, NC);
 162
 163     if (is_stdio_uart) {
 164         stdio_uart_inited = 1;
 165         memcpy(&stdio_uart, obj, sizeof(serial_t));
 166     }
 167 }
 168
 169 void serial_free(serial_t *obj) {
 170     uart_data[obj->index].serial_irq_id = 0;
 171 }
 172
 173 // serial_baud
 174 // set the baud rate, taking in to account the current SystemFrequency
 175 void serial_baud(serial_t *obj, int baudrate) {
 176     uint32_t PCLK = SystemCoreClock;
 177
 178     // First we check to see if the basic divide with no DivAddVal/MulVal
 179     // ratio gives us an integer result. If it does, we set DivAddVal = 0,
 180     // MulVal = 1. Otherwise, we search the valid ratio value range to find
 181     // the closest match. This could be more elegant, using search methods
 182     // and/or lookup tables, but the brute force method is not that much
 183     // slower, and is more maintainable.
 184     uint16_t DL = PCLK / (16 * baudrate);
 185
 186     uint8_t DivAddVal = 0;
 187     uint8_t MulVal = 1;
 188     int hit = 0;
 189     uint16_t dlv;
 190     uint8_t mv, dav;
 191     if ((PCLK % (16 * baudrate)) != 0) {     // Checking for zero remainder
 192         int err_best = baudrate, b;
 193         for (mv = 1; mv < 16 && !hit; mv++)
 194         {
 195             for (dav = 0; dav < mv; dav++)
 196             {
 197                 // baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
 198                 // solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
 199                 // mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
 200                 // for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
 201                 // note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
 202
 203                 if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
 204                     dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
 205                 else // 2 bits headroom, use more precision
 206                     dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
 207
 208                 // datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
 209                 if (dlv == 0)
 210                     dlv = 1;
 211
 212                 // datasheet says if dav > 0 then DL must be >= 2
 213                 if ((dav > 0) && (dlv < 2))
 214                     dlv = 2;
 215
 216                 // integer rearrangement of the baudrate equation (with rounding)
 217                 b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
 218
 219                 // check to see how we went
 220                 b = abs(b - baudrate);
 221                 if (b < err_best)
 222                 {
 223                     err_best  = b;
 224
 225                     DL        = dlv;
 226                     MulVal    = mv;
 227                     DivAddVal = dav;
 228
 229                     if (b == baudrate)
 230                     {
 231                         hit = 1;
 232                         break;
 233                     }
 234                 }
 235             }
 236         }
 237     }
 238
 239     // set LCR[DLAB] to enable writing to divider registers
 240     obj->uart->LCR |= (1 << 7);
 241
 242     // set divider values
 243     obj->uart->DLM = (DL >> 8) & 0xFF;
 244     obj->uart->DLL = (DL >> 0) & 0xFF;
 245     obj->uart->FDR = (uint32_t) DivAddVal << 0
 246                    | (uint32_t) MulVal    << 4;
 247
 248     // clear LCR[DLAB]
 249     obj->uart->LCR &= ~(1 << 7);
 250 }
 251
 252 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
 253     // 0: 1 stop bits, 1: 2 stop bits
 254     if (stop_bits != 1 && stop_bits != 2) {
 255         error("Invalid stop bits specified");
 256     }
 257     stop_bits -= 1;
 258
 259     // 0: 5 data bits ... 3: 8 data bits
 260     if (data_bits < 5 || data_bits > 8) {
 261         error("Invalid number of bits (%d) in serial format, should be 5..8", data_bits);
 262     }
 263     data_bits -= 5;
 264
 265     int parity_enable, parity_select;
 266     switch (parity) {
 267         case ParityNone: parity_enable = 0; parity_select = 0; break;
 268         case ParityOdd : parity_enable = 1; parity_select = 0; break;
 269         case ParityEven: parity_enable = 1; parity_select = 1; break;
 270         case ParityForced1: parity_enable = 1; parity_select = 2; break;
 271         case ParityForced0: parity_enable = 1; parity_select = 3; break;
 272         default:
 273             error("Invalid serial parity setting");
 274             return;
 275     }
 276
 277     obj->uart->LCR = data_bits            << 0
 278                    | stop_bits            << 2
 279                    | parity_enable        << 3
 280                    | parity_select        << 4;
 281 }
 282
 283 /******************************************************************************
 284  * INTERRUPTS HANDLING
 285  ******************************************************************************/
 286 static inline void uart_irq(uint32_t iir, uint32_t index, LPC_USART_T *puart) {
 287     // [Chapter 14] LPC17xx UART0/2/3: UARTn Interrupt Handling
 288     SerialIrq irq_type;
 289     switch (iir) {
 290         case 1: irq_type = TxIrq; break;
 291         case 2: irq_type = RxIrq; break;
 292         default: return;
 293     }
 294     if ((RxIrq == irq_type) && (NC != uart_data[index].sw_rts.pin)) {
 295         gpio_write(&uart_data[index].sw_rts, 1);
 296         // Disable interrupt if it wasn't enabled by other part of the application
 297         if (!uart_data[index].rx_irq_set_api)
 298             puart->IER &= ~(1 << RxIrq);
 299     }
 300     if (uart_data[index].serial_irq_id != 0)
 301         if ((irq_type != RxIrq) || (uart_data[index].rx_irq_set_api))
 302             irq_handler(uart_data[index].serial_irq_id, irq_type);
 303 }
 304
 305 void uart0_irq() {uart_irq((LPC_USART0->IIR >> 1) & 0x7, 0, (LPC_USART_T*)LPC_USART0);}
 306 void uart1_irq() {uart_irq((LPC_UART1->IIR  >> 1) & 0x7, 1, (LPC_USART_T*)LPC_UART1);}
 307 void uart2_irq() {uart_irq((LPC_USART2->IIR >> 1) & 0x7, 2, (LPC_USART_T*)LPC_USART2);}
 308 void uart3_irq() {uart_irq((LPC_USART3->IIR >> 1) & 0x7, 3, (LPC_USART_T*)LPC_USART3);}
 309
 310 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
 311     irq_handler = handler;
 312     uart_data[obj->index].serial_irq_id = id;
 313 }
 314
 315 static void serial_irq_set_internal(serial_t *obj, SerialIrq irq, uint32_t enable) {
 316     IRQn_Type irq_n = (IRQn_Type)0;
 317     uint32_t vector = 0;
 318     switch ((int)obj->uart) {
 319         case UART_0: irq_n=USART0_IRQn; vector = (uint32_t)&uart0_irq; break;
 320         case UART_1: irq_n=UART1_IRQn;  vector = (uint32_t)&uart1_irq; break;
 321         case UART_2: irq_n=USART2_IRQn; vector = (uint32_t)&uart2_irq; break;
 322         case UART_3: irq_n=USART3_IRQn; vector = (uint32_t)&uart3_irq; break;
 323     }
 324
 325     if (enable) {
 326         obj->uart->IER |= 1 << irq;
 327         NVIC_SetVector(irq_n, vector);
 328         NVIC_EnableIRQ(irq_n);
 329     } else if ((TxIrq == irq) || (uart_data[obj->index].rx_irq_set_api + uart_data[obj->index].rx_irq_set_flow == 0)) { // disable
 330         int all_disabled = 0;
 331         SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
 332         obj->uart->IER &= ~(1 << irq);
 333         all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
 334         if (all_disabled)
 335             NVIC_DisableIRQ(irq_n);
 336     }
 337 }
 338
 339 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
 340     if (RxIrq == irq)
 341         uart_data[obj->index].rx_irq_set_api = enable;
 342     serial_irq_set_internal(obj, irq, enable);
 343 }
 344
 345 #if (DEVICE_SERIAL_FC)
 346 static void serial_flow_irq_set(serial_t *obj, uint32_t enable) {
 347     uart_data[obj->index].rx_irq_set_flow = enable;
 348     serial_irq_set_internal(obj, RxIrq, enable);
 349 }
 350 #endif
 351
 352 /******************************************************************************
 353  * READ/WRITE
 354  ******************************************************************************/
 355 int serial_getc(serial_t *obj) {
 356     while (!serial_readable(obj));
 357     int data = obj->uart->RBR;
 358     if (NC != uart_data[obj->index].sw_rts.pin) {
 359         gpio_write(&uart_data[obj->index].sw_rts, 0);
 360         obj->uart->IER |= 1 << RxIrq;
 361     }
 362     return data;
 363 }
 364
 365 void serial_putc(serial_t *obj, int c) {
 366     while (!serial_writable(obj));
 367     obj->uart->THR = c;
 368     uart_data[obj->index].count++;
 369 }
 370
 371 int serial_readable(serial_t *obj) {
 372     return obj->uart->LSR & 0x01;
 373 }
 374
 375 int serial_writable(serial_t *obj) {
 376     int isWritable = 1;
 377     if (NC != uart_data[obj->index].sw_cts.pin)
 378         isWritable = (gpio_read(&uart_data[obj->index].sw_cts) == 0) && (obj->uart->LSR & 0x40);  //If flow control: writable if CTS low + UART done
 379     else {
 380         if (obj->uart->LSR & 0x20)
 381             uart_data[obj->index].count = 0;
 382         else if (uart_data[obj->index].count >= 16)
 383             isWritable = 0;
 384     }
 385     return isWritable;
 386 }
 387
 388 void serial_clear(serial_t *obj) {
 389     obj->uart->FCR = 1 << 0  // FIFO Enable - 0 = Disables, 1 = Enabled
 390                    | 1 << 1  // rx FIFO reset
 391                    | 1 << 2  // tx FIFO reset
 392                    | 0 << 6; // interrupt depth
 393 }
 394
 395 void serial_pinout_tx(PinName tx) {
 396     pinmap_pinout(tx, PinMap_UART_TX);
 397 }
 398
 399 void serial_break_set(serial_t *obj) {
 400     obj->uart->LCR |= (1 << 6);
 401 }
 402
 403 void serial_break_clear(serial_t *obj) {
 404     obj->uart->LCR &= ~(1 << 6);
 405 }
 406
 407 void serial_set_flow_control(serial_t *obj, FlowControl type, PinName rxflow, PinName txflow) {
 408 #if (DEVICE_SERIAL_FC)
 409 #endif
 410 }