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Development branch of the mbed library sources. This library is kept in synch with the latest changes from the mbed SDK and it is not guaranteed to work.

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The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.

Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_NXP/TARGET_LPC11XX_11CXX/serial_api.c@30:91c1d09ada54, 2013-09-25 (annotated)

Committer:
mbed_official
Date:
Wed Sep 25 10:30:04 2013 +0100
Revision:
30:91c1d09ada54
Child:
51:7838415c99e7
Synchronized with git revision 8f57c1e84759991fa81ede0da2b4aabe8530fa09

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 30:91c1d09ada54 1 /* mbed Microcontroller Library
mbed_official 30:91c1d09ada54 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 30:91c1d09ada54 3 *
mbed_official 30:91c1d09ada54 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 30:91c1d09ada54 5 * you may not use this file except in compliance with the License.
mbed_official 30:91c1d09ada54 6 * You may obtain a copy of the License at
mbed_official 30:91c1d09ada54 7 *
mbed_official 30:91c1d09ada54 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 30:91c1d09ada54 9 *
mbed_official 30:91c1d09ada54 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 30:91c1d09ada54 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 30:91c1d09ada54 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 30:91c1d09ada54 13 * See the License for the specific language governing permissions and
mbed_official 30:91c1d09ada54 14 * limitations under the License.
mbed_official 30:91c1d09ada54 15 */
mbed_official 30:91c1d09ada54 16 // math.h required for floating point operations for baud rate calculation
mbed_official 30:91c1d09ada54 17 #include <math.h>
mbed_official 30:91c1d09ada54 18 #include <string.h>
mbed_official 30:91c1d09ada54 19
mbed_official 30:91c1d09ada54 20 #include "serial_api.h"
mbed_official 30:91c1d09ada54 21 #include "cmsis.h"
mbed_official 30:91c1d09ada54 22 #include "pinmap.h"
mbed_official 30:91c1d09ada54 23 #include "error.h"
mbed_official 30:91c1d09ada54 24
mbed_official 30:91c1d09ada54 25 /******************************************************************************
mbed_official 30:91c1d09ada54 26 * INITIALIZATION
mbed_official 30:91c1d09ada54 27 ******************************************************************************/
mbed_official 30:91c1d09ada54 28 #define UART_NUM 1
mbed_official 30:91c1d09ada54 29
mbed_official 30:91c1d09ada54 30 static const PinMap PinMap_UART_TX[] = {
mbed_official 30:91c1d09ada54 31 {P2_8 , UART_0, 0x02},
mbed_official 30:91c1d09ada54 32 {P3_5 , UART_0, 0x02},
mbed_official 30:91c1d09ada54 33 {P3_0 , UART_0, 0x03},
mbed_official 30:91c1d09ada54 34 {P1_7 , UART_0, 0x01},
mbed_official 30:91c1d09ada54 35 {NC , NC , 0x00}
mbed_official 30:91c1d09ada54 36 };
mbed_official 30:91c1d09ada54 37
mbed_official 30:91c1d09ada54 38 static const PinMap PinMap_UART_RX[] = {
mbed_official 30:91c1d09ada54 39 {P2_7 , UART_0, 0x02},
mbed_official 30:91c1d09ada54 40 {P3_4 , UART_0, 0x02},
mbed_official 30:91c1d09ada54 41 {P3_1 , UART_0, 0x03},
mbed_official 30:91c1d09ada54 42 {P1_6 , UART_0, 0x01},
mbed_official 30:91c1d09ada54 43 {NC , NC , 0x00}
mbed_official 30:91c1d09ada54 44 };
mbed_official 30:91c1d09ada54 45
mbed_official 30:91c1d09ada54 46 static uint32_t serial_irq_ids[UART_NUM] = {0};
mbed_official 30:91c1d09ada54 47 static uart_irq_handler irq_handler;
mbed_official 30:91c1d09ada54 48
mbed_official 30:91c1d09ada54 49 int stdio_uart_inited = 0;
mbed_official 30:91c1d09ada54 50 serial_t stdio_uart;
mbed_official 30:91c1d09ada54 51
mbed_official 30:91c1d09ada54 52 void serial_init(serial_t *obj, PinName tx, PinName rx) {
mbed_official 30:91c1d09ada54 53 int is_stdio_uart = 0;
mbed_official 30:91c1d09ada54 54
mbed_official 30:91c1d09ada54 55 // determine the UART to use
mbed_official 30:91c1d09ada54 56 UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX);
mbed_official 30:91c1d09ada54 57 UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX);
mbed_official 30:91c1d09ada54 58 UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx);
mbed_official 30:91c1d09ada54 59 if ((int)uart == NC) {
mbed_official 30:91c1d09ada54 60 error("Serial pinout mapping failed");
mbed_official 30:91c1d09ada54 61 }
mbed_official 30:91c1d09ada54 62
mbed_official 30:91c1d09ada54 63 obj->uart = (LPC_UART_TypeDef *)uart;
mbed_official 30:91c1d09ada54 64 LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12);
mbed_official 30:91c1d09ada54 65
mbed_official 30:91c1d09ada54 66 // enable fifos and default rx trigger level
mbed_official 30:91c1d09ada54 67 obj->uart->FCR = 1 << 0 // FIFO Enable - 0 = Disables, 1 = Enabled
mbed_official 30:91c1d09ada54 68 | 0 << 1 // Rx Fifo Reset
mbed_official 30:91c1d09ada54 69 | 0 << 2 // Tx Fifo Reset
mbed_official 30:91c1d09ada54 70 | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars
mbed_official 30:91c1d09ada54 71
mbed_official 30:91c1d09ada54 72 // disable irqs
mbed_official 30:91c1d09ada54 73 obj->uart->IER = 0 << 0 // Rx Data available irq enable
mbed_official 30:91c1d09ada54 74 | 0 << 1 // Tx Fifo empty irq enable
mbed_official 30:91c1d09ada54 75 | 0 << 2; // Rx Line Status irq enable
mbed_official 30:91c1d09ada54 76
mbed_official 30:91c1d09ada54 77 // set default baud rate and format
mbed_official 30:91c1d09ada54 78 serial_baud (obj, 9600);
mbed_official 30:91c1d09ada54 79 serial_format(obj, 8, ParityNone, 1);
mbed_official 30:91c1d09ada54 80
mbed_official 30:91c1d09ada54 81 // pinout the chosen uart
mbed_official 30:91c1d09ada54 82 pinmap_pinout(tx, PinMap_UART_TX);
mbed_official 30:91c1d09ada54 83 pinmap_pinout(rx, PinMap_UART_RX);
mbed_official 30:91c1d09ada54 84
mbed_official 30:91c1d09ada54 85 // set rx/tx pins in PullUp mode
mbed_official 30:91c1d09ada54 86 pin_mode(tx, PullUp);
mbed_official 30:91c1d09ada54 87 pin_mode(rx, PullUp);
mbed_official 30:91c1d09ada54 88
mbed_official 30:91c1d09ada54 89 switch (uart) {
mbed_official 30:91c1d09ada54 90 case UART_0: obj->index = 0; break;
mbed_official 30:91c1d09ada54 91 }
mbed_official 30:91c1d09ada54 92
mbed_official 30:91c1d09ada54 93 is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
mbed_official 30:91c1d09ada54 94
mbed_official 30:91c1d09ada54 95 if (is_stdio_uart) {
mbed_official 30:91c1d09ada54 96 stdio_uart_inited = 1;
mbed_official 30:91c1d09ada54 97 memcpy(&stdio_uart, obj, sizeof(serial_t));
mbed_official 30:91c1d09ada54 98 }
mbed_official 30:91c1d09ada54 99 }
mbed_official 30:91c1d09ada54 100
mbed_official 30:91c1d09ada54 101 void serial_free(serial_t *obj) {
mbed_official 30:91c1d09ada54 102 serial_irq_ids[obj->index] = 0;
mbed_official 30:91c1d09ada54 103 }
mbed_official 30:91c1d09ada54 104
mbed_official 30:91c1d09ada54 105 // serial_baud
mbed_official 30:91c1d09ada54 106 // set the baud rate, taking in to account the current SystemFrequency
mbed_official 30:91c1d09ada54 107 void serial_baud(serial_t *obj, int baudrate) {
mbed_official 30:91c1d09ada54 108 LPC_SYSCON->UARTCLKDIV = 0x1;
mbed_official 30:91c1d09ada54 109 uint32_t PCLK = SystemCoreClock;
mbed_official 30:91c1d09ada54 110 // First we check to see if the basic divide with no DivAddVal/MulVal
mbed_official 30:91c1d09ada54 111 // ratio gives us an integer result. If it does, we set DivAddVal = 0,
mbed_official 30:91c1d09ada54 112 // MulVal = 1. Otherwise, we search the valid ratio value range to find
mbed_official 30:91c1d09ada54 113 // the closest match. This could be more elegant, using search methods
mbed_official 30:91c1d09ada54 114 // and/or lookup tables, but the brute force method is not that much
mbed_official 30:91c1d09ada54 115 // slower, and is more maintainable.
mbed_official 30:91c1d09ada54 116 uint16_t DL = PCLK / (16 * baudrate);
mbed_official 30:91c1d09ada54 117
mbed_official 30:91c1d09ada54 118 uint8_t DivAddVal = 0;
mbed_official 30:91c1d09ada54 119 uint8_t MulVal = 1;
mbed_official 30:91c1d09ada54 120 int hit = 0;
mbed_official 30:91c1d09ada54 121 uint16_t dlv;
mbed_official 30:91c1d09ada54 122 uint8_t mv, dav;
mbed_official 30:91c1d09ada54 123 if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
mbed_official 30:91c1d09ada54 124 float err_best = (float) baudrate;
mbed_official 30:91c1d09ada54 125 uint16_t dlmax = DL;
mbed_official 30:91c1d09ada54 126 for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
mbed_official 30:91c1d09ada54 127 for ( mv = 1; mv <= 15; mv++) {
mbed_official 30:91c1d09ada54 128 for ( dav = 1; dav < mv; dav++) {
mbed_official 30:91c1d09ada54 129 float ratio = 1.0f + ((float) dav / (float) mv);
mbed_official 30:91c1d09ada54 130 float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
mbed_official 30:91c1d09ada54 131 float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
mbed_official 30:91c1d09ada54 132 if (err < err_best) {
mbed_official 30:91c1d09ada54 133 DL = dlv;
mbed_official 30:91c1d09ada54 134 DivAddVal = dav;
mbed_official 30:91c1d09ada54 135 MulVal = mv;
mbed_official 30:91c1d09ada54 136 err_best = err;
mbed_official 30:91c1d09ada54 137 if (err < 0.001f) {
mbed_official 30:91c1d09ada54 138 hit = 1;
mbed_official 30:91c1d09ada54 139 }
mbed_official 30:91c1d09ada54 140 }
mbed_official 30:91c1d09ada54 141 }
mbed_official 30:91c1d09ada54 142 }
mbed_official 30:91c1d09ada54 143 }
mbed_official 30:91c1d09ada54 144 }
mbed_official 30:91c1d09ada54 145
mbed_official 30:91c1d09ada54 146 // set LCR[DLAB] to enable writing to divider registers
mbed_official 30:91c1d09ada54 147 obj->uart->LCR |= (1 << 7);
mbed_official 30:91c1d09ada54 148
mbed_official 30:91c1d09ada54 149 // set divider values
mbed_official 30:91c1d09ada54 150 obj->uart->DLM = (DL >> 8) & 0xFF;
mbed_official 30:91c1d09ada54 151 obj->uart->DLL = (DL >> 0) & 0xFF;
mbed_official 30:91c1d09ada54 152 obj->uart->FDR = (uint32_t) DivAddVal << 0
mbed_official 30:91c1d09ada54 153 | (uint32_t) MulVal << 4;
mbed_official 30:91c1d09ada54 154
mbed_official 30:91c1d09ada54 155 // clear LCR[DLAB]
mbed_official 30:91c1d09ada54 156 obj->uart->LCR &= ~(1 << 7);
mbed_official 30:91c1d09ada54 157 }
mbed_official 30:91c1d09ada54 158
mbed_official 30:91c1d09ada54 159 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
mbed_official 30:91c1d09ada54 160 // 0: 1 stop bits, 1: 2 stop bits
mbed_official 30:91c1d09ada54 161 if (stop_bits != 1 && stop_bits != 2) {
mbed_official 30:91c1d09ada54 162 error("Invalid stop bits specified");
mbed_official 30:91c1d09ada54 163 }
mbed_official 30:91c1d09ada54 164 stop_bits -= 1;
mbed_official 30:91c1d09ada54 165
mbed_official 30:91c1d09ada54 166 // 0: 5 data bits ... 3: 8 data bits
mbed_official 30:91c1d09ada54 167 if (data_bits < 5 || data_bits > 8) {
mbed_official 30:91c1d09ada54 168 error("Invalid number of bits (%d) in serial format, should be 5..8", data_bits);
mbed_official 30:91c1d09ada54 169 }
mbed_official 30:91c1d09ada54 170 data_bits -= 5;
mbed_official 30:91c1d09ada54 171
mbed_official 30:91c1d09ada54 172 int parity_enable, parity_select;
mbed_official 30:91c1d09ada54 173 switch (parity) {
mbed_official 30:91c1d09ada54 174 case ParityNone: parity_enable = 0; parity_select = 0; break;
mbed_official 30:91c1d09ada54 175 case ParityOdd : parity_enable = 1; parity_select = 0; break;
mbed_official 30:91c1d09ada54 176 case ParityEven: parity_enable = 1; parity_select = 1; break;
mbed_official 30:91c1d09ada54 177 case ParityForced1: parity_enable = 1; parity_select = 2; break;
mbed_official 30:91c1d09ada54 178 case ParityForced0: parity_enable = 1; parity_select = 3; break;
mbed_official 30:91c1d09ada54 179 default:
mbed_official 30:91c1d09ada54 180 error("Invalid serial parity setting");
mbed_official 30:91c1d09ada54 181 return;
mbed_official 30:91c1d09ada54 182 }
mbed_official 30:91c1d09ada54 183
mbed_official 30:91c1d09ada54 184 obj->uart->LCR = data_bits << 0
mbed_official 30:91c1d09ada54 185 | stop_bits << 2
mbed_official 30:91c1d09ada54 186 | parity_enable << 3
mbed_official 30:91c1d09ada54 187 | parity_select << 4;
mbed_official 30:91c1d09ada54 188 }
mbed_official 30:91c1d09ada54 189
mbed_official 30:91c1d09ada54 190 /******************************************************************************
mbed_official 30:91c1d09ada54 191 * INTERRUPTS HANDLING
mbed_official 30:91c1d09ada54 192 ******************************************************************************/
mbed_official 30:91c1d09ada54 193 static inline void uart_irq(uint32_t iir, uint32_t index) {
mbed_official 30:91c1d09ada54 194 // [Chapter 14] LPC17xx UART0/2/3: UARTn Interrupt Handling
mbed_official 30:91c1d09ada54 195 SerialIrq irq_type;
mbed_official 30:91c1d09ada54 196 switch (iir) {
mbed_official 30:91c1d09ada54 197 case 1: irq_type = TxIrq; break;
mbed_official 30:91c1d09ada54 198 case 2: irq_type = RxIrq; break;
mbed_official 30:91c1d09ada54 199 default: return;
mbed_official 30:91c1d09ada54 200 }
mbed_official 30:91c1d09ada54 201
mbed_official 30:91c1d09ada54 202 if (serial_irq_ids[index] != 0)
mbed_official 30:91c1d09ada54 203 irq_handler(serial_irq_ids[index], irq_type);
mbed_official 30:91c1d09ada54 204 }
mbed_official 30:91c1d09ada54 205
mbed_official 30:91c1d09ada54 206 void uart0_irq() {uart_irq((LPC_UART->IIR >> 1) & 0x7, 0);}
mbed_official 30:91c1d09ada54 207
mbed_official 30:91c1d09ada54 208 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
mbed_official 30:91c1d09ada54 209 irq_handler = handler;
mbed_official 30:91c1d09ada54 210 serial_irq_ids[obj->index] = id;
mbed_official 30:91c1d09ada54 211 }
mbed_official 30:91c1d09ada54 212
mbed_official 30:91c1d09ada54 213 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
mbed_official 30:91c1d09ada54 214 IRQn_Type irq_n = (IRQn_Type)0;
mbed_official 30:91c1d09ada54 215 uint32_t vector = 0;
mbed_official 30:91c1d09ada54 216 switch ((int)obj->uart) {
mbed_official 30:91c1d09ada54 217 case UART_0:
mbed_official 30:91c1d09ada54 218 irq_n=UART_IRQn;
mbed_official 30:91c1d09ada54 219 vector = (uint32_t)&uart0_irq;
mbed_official 30:91c1d09ada54 220 break;
mbed_official 30:91c1d09ada54 221 default:
mbed_official 30:91c1d09ada54 222 return;
mbed_official 30:91c1d09ada54 223 }
mbed_official 30:91c1d09ada54 224
mbed_official 30:91c1d09ada54 225 if (enable) {
mbed_official 30:91c1d09ada54 226 obj->uart->IER |= 1 << irq;
mbed_official 30:91c1d09ada54 227 NVIC_SetVector(irq_n, vector);
mbed_official 30:91c1d09ada54 228 NVIC_EnableIRQ(irq_n);
mbed_official 30:91c1d09ada54 229 } else { // disable
mbed_official 30:91c1d09ada54 230 int all_disabled = 0;
mbed_official 30:91c1d09ada54 231 SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
mbed_official 30:91c1d09ada54 232
mbed_official 30:91c1d09ada54 233 obj->uart->IER &= ~(1 << irq);
mbed_official 30:91c1d09ada54 234 all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
mbed_official 30:91c1d09ada54 235
mbed_official 30:91c1d09ada54 236 if (all_disabled)
mbed_official 30:91c1d09ada54 237 NVIC_DisableIRQ(irq_n);
mbed_official 30:91c1d09ada54 238 }
mbed_official 30:91c1d09ada54 239 }
mbed_official 30:91c1d09ada54 240
mbed_official 30:91c1d09ada54 241 /******************************************************************************
mbed_official 30:91c1d09ada54 242 * READ/WRITE
mbed_official 30:91c1d09ada54 243 ******************************************************************************/
mbed_official 30:91c1d09ada54 244 int serial_getc(serial_t *obj) {
mbed_official 30:91c1d09ada54 245 while (!serial_readable(obj));
mbed_official 30:91c1d09ada54 246 return obj->uart->RBR;
mbed_official 30:91c1d09ada54 247 }
mbed_official 30:91c1d09ada54 248
mbed_official 30:91c1d09ada54 249 void serial_putc(serial_t *obj, int c) {
mbed_official 30:91c1d09ada54 250 while (!serial_writable(obj));
mbed_official 30:91c1d09ada54 251 obj->uart->THR = c;
mbed_official 30:91c1d09ada54 252 }
mbed_official 30:91c1d09ada54 253
mbed_official 30:91c1d09ada54 254 int serial_readable(serial_t *obj) {
mbed_official 30:91c1d09ada54 255 return obj->uart->LSR & 0x01;
mbed_official 30:91c1d09ada54 256 }
mbed_official 30:91c1d09ada54 257
mbed_official 30:91c1d09ada54 258 int serial_writable(serial_t *obj) {
mbed_official 30:91c1d09ada54 259 return obj->uart->LSR & 0x20;
mbed_official 30:91c1d09ada54 260 }
mbed_official 30:91c1d09ada54 261
mbed_official 30:91c1d09ada54 262 void serial_clear(serial_t *obj) {
mbed_official 30:91c1d09ada54 263 obj->uart->FCR = 1 << 1 // rx FIFO reset
mbed_official 30:91c1d09ada54 264 | 1 << 2 // tx FIFO reset
mbed_official 30:91c1d09ada54 265 | 0 << 6; // interrupt depth
mbed_official 30:91c1d09ada54 266 }
mbed_official 30:91c1d09ada54 267
mbed_official 30:91c1d09ada54 268 void serial_pinout_tx(PinName tx) {
mbed_official 30:91c1d09ada54 269 pinmap_pinout(tx, PinMap_UART_TX);
mbed_official 30:91c1d09ada54 270 }
mbed_official 30:91c1d09ada54 271
mbed_official 30:91c1d09ada54 272 void serial_break_clear(serial_t *obj) {
mbed_official 30:91c1d09ada54 273 obj->uart->LCR &= ~(1 << 6);
mbed_official 30:91c1d09ada54 274 }
mbed_official 30:91c1d09ada54 275
mbed_official 30:91c1d09ada54 276 void serial_break_set(serial_t *obj) {
mbed_official 30:91c1d09ada54 277 obj->uart->LCR |= 1 << 6;
mbed_official 30:91c1d09ada54 278 }