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mbed SDK library sources

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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_LPC11UXX/serial_api.c@59:ef93cc6bbf65, 2013-12-16 (annotated)

Committer:
mbed_official
Date:
Mon Dec 16 09:15:05 2013 +0000
Revision:
59:ef93cc6bbf65
Parent:
51:7838415c99e7 
Synchronized with git revision 5dea203d16a93915c80553c1d95b26625bc077f8



Full URL: https://github.com/mbedmicro/mbed/commit/5dea203d16a93915c80553c1d95b26625bc077f8/

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 13:0645d8841f51 1 /* mbed Microcontroller Library
bogdanm 13:0645d8841f51 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 13:0645d8841f51 3 *
bogdanm 13:0645d8841f51 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 13:0645d8841f51 5 * you may not use this file except in compliance with the License.
bogdanm 13:0645d8841f51 6 * You may obtain a copy of the License at
bogdanm 13:0645d8841f51 7 *
bogdanm 13:0645d8841f51 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 13:0645d8841f51 9 *
bogdanm 13:0645d8841f51 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 13:0645d8841f51 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 13:0645d8841f51 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 13:0645d8841f51 13 * See the License for the specific language governing permissions and
bogdanm 13:0645d8841f51 14 * limitations under the License.
bogdanm 13:0645d8841f51 15 */
bogdanm 13:0645d8841f51 16 // math.h required for floating point operations for baud rate calculation
bogdanm 13:0645d8841f51 17 #include <math.h>
bogdanm 13:0645d8841f51 18 #include <string.h>
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 #include "serial_api.h"
bogdanm 13:0645d8841f51 21 #include "cmsis.h"
bogdanm 13:0645d8841f51 22 #include "pinmap.h"
bogdanm 13:0645d8841f51 23 #include "error.h"
bogdanm 13:0645d8841f51 24
bogdanm 13:0645d8841f51 25 /******************************************************************************
bogdanm 13:0645d8841f51 26 * INITIALIZATION
bogdanm 13:0645d8841f51 27 ******************************************************************************/
bogdanm 13:0645d8841f51 28 #define UART_NUM 1
bogdanm 13:0645d8841f51 29
bogdanm 13:0645d8841f51 30 static const PinMap PinMap_UART_TX[] = {
bogdanm 13:0645d8841f51 31 {P0_19, UART_0, 1},
bogdanm 13:0645d8841f51 32 {P1_13, UART_0, 3},
bogdanm 13:0645d8841f51 33 {P1_27, UART_0, 2},
bogdanm 13:0645d8841f51 34 { NC , NC , 0}
bogdanm 13:0645d8841f51 35 };
bogdanm 13:0645d8841f51 36
bogdanm 13:0645d8841f51 37 static const PinMap PinMap_UART_RX[] = {
bogdanm 13:0645d8841f51 38 {P0_18, UART_0, 1},
bogdanm 13:0645d8841f51 39 {P1_14, UART_0, 3},
bogdanm 13:0645d8841f51 40 {P1_26, UART_0, 2},
bogdanm 13:0645d8841f51 41 {NC , NC , 0}
bogdanm 13:0645d8841f51 42 };
bogdanm 13:0645d8841f51 43
bogdanm 13:0645d8841f51 44 static uint32_t serial_irq_ids[UART_NUM] = {0};
bogdanm 13:0645d8841f51 45 static uart_irq_handler irq_handler;
bogdanm 13:0645d8841f51 46
bogdanm 13:0645d8841f51 47 int stdio_uart_inited = 0;
bogdanm 13:0645d8841f51 48 serial_t stdio_uart;
bogdanm 13:0645d8841f51 49
bogdanm 13:0645d8841f51 50 void serial_init(serial_t *obj, PinName tx, PinName rx) {
bogdanm 13:0645d8841f51 51 int is_stdio_uart = 0;
bogdanm 13:0645d8841f51 52
bogdanm 13:0645d8841f51 53 // determine the UART to use
bogdanm 13:0645d8841f51 54 UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX);
bogdanm 13:0645d8841f51 55 UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX);
bogdanm 13:0645d8841f51 56 UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx);
bogdanm 13:0645d8841f51 57 if ((int)uart == NC) {
bogdanm 13:0645d8841f51 58 error("Serial pinout mapping failed");
bogdanm 13:0645d8841f51 59 }
bogdanm 13:0645d8841f51 60
bogdanm 13:0645d8841f51 61 obj->uart = (LPC_USART_Type *)uart;
bogdanm 13:0645d8841f51 62 LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12);
bogdanm 13:0645d8841f51 63
bogdanm 13:0645d8841f51 64 // [TODO] Consider more elegant approach
bogdanm 13:0645d8841f51 65 // disconnect USBTX/RX mapping mux, for case when switching ports
mbed_official 59:ef93cc6bbf65 66 #ifdef USBTX
bogdanm 13:0645d8841f51 67 pin_function(USBTX, 0);
bogdanm 13:0645d8841f51 68 pin_function(USBRX, 0);
mbed_official 59:ef93cc6bbf65 69 #endif
mbed_official 59:ef93cc6bbf65 70
bogdanm 13:0645d8841f51 71 // enable fifos and default rx trigger level
bogdanm 13:0645d8841f51 72 obj->uart->FCR = 1 << 0 // FIFO Enable - 0 = Disables, 1 = Enabled
bogdanm 13:0645d8841f51 73 | 0 << 1 // Rx Fifo Reset
bogdanm 13:0645d8841f51 74 | 0 << 2 // Tx Fifo Reset
bogdanm 13:0645d8841f51 75 | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars
bogdanm 13:0645d8841f51 76
bogdanm 13:0645d8841f51 77 // disable irqs
bogdanm 13:0645d8841f51 78 obj->uart->IER = 0 << 0 // Rx Data available irq enable
bogdanm 13:0645d8841f51 79 | 0 << 1 // Tx Fifo empty irq enable
bogdanm 13:0645d8841f51 80 | 0 << 2; // Rx Line Status irq enable
bogdanm 13:0645d8841f51 81
bogdanm 13:0645d8841f51 82 // set default baud rate and format
bogdanm 13:0645d8841f51 83 serial_baud (obj, 9600);
bogdanm 13:0645d8841f51 84 serial_format(obj, 8, ParityNone, 1);
bogdanm 13:0645d8841f51 85
bogdanm 13:0645d8841f51 86 // pinout the chosen uart
bogdanm 13:0645d8841f51 87 pinmap_pinout(tx, PinMap_UART_TX);
bogdanm 13:0645d8841f51 88 pinmap_pinout(rx, PinMap_UART_RX);
bogdanm 13:0645d8841f51 89
bogdanm 13:0645d8841f51 90 // set rx/tx pins in PullUp mode
bogdanm 13:0645d8841f51 91 pin_mode(tx, PullUp);
bogdanm 13:0645d8841f51 92 pin_mode(rx, PullUp);
bogdanm 13:0645d8841f51 93
bogdanm 13:0645d8841f51 94 switch (uart) {
bogdanm 13:0645d8841f51 95 case UART_0: obj->index = 0; break;
bogdanm 13:0645d8841f51 96 }
bogdanm 13:0645d8841f51 97
bogdanm 13:0645d8841f51 98 is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
bogdanm 13:0645d8841f51 99
bogdanm 13:0645d8841f51 100 if (is_stdio_uart) {
bogdanm 13:0645d8841f51 101 stdio_uart_inited = 1;
bogdanm 13:0645d8841f51 102 memcpy(&stdio_uart, obj, sizeof(serial_t));
bogdanm 13:0645d8841f51 103 }
bogdanm 13:0645d8841f51 104 }
bogdanm 13:0645d8841f51 105
bogdanm 13:0645d8841f51 106 void serial_free(serial_t *obj) {
bogdanm 13:0645d8841f51 107 serial_irq_ids[obj->index] = 0;
bogdanm 13:0645d8841f51 108 }
bogdanm 13:0645d8841f51 109
bogdanm 13:0645d8841f51 110 // serial_baud
bogdanm 13:0645d8841f51 111 // set the baud rate, taking in to account the current SystemFrequency
bogdanm 13:0645d8841f51 112 void serial_baud(serial_t *obj, int baudrate) {
bogdanm 13:0645d8841f51 113 LPC_SYSCON->UARTCLKDIV = 0x1;
bogdanm 13:0645d8841f51 114 uint32_t PCLK = SystemCoreClock;
bogdanm 13:0645d8841f51 115 // First we check to see if the basic divide with no DivAddVal/MulVal
bogdanm 13:0645d8841f51 116 // ratio gives us an integer result. If it does, we set DivAddVal = 0,
bogdanm 13:0645d8841f51 117 // MulVal = 1. Otherwise, we search the valid ratio value range to find
bogdanm 13:0645d8841f51 118 // the closest match. This could be more elegant, using search methods
bogdanm 13:0645d8841f51 119 // and/or lookup tables, but the brute force method is not that much
bogdanm 13:0645d8841f51 120 // slower, and is more maintainable.
bogdanm 13:0645d8841f51 121 uint16_t DL = PCLK / (16 * baudrate);
bogdanm 13:0645d8841f51 122
bogdanm 13:0645d8841f51 123 uint8_t DivAddVal = 0;
bogdanm 13:0645d8841f51 124 uint8_t MulVal = 1;
bogdanm 13:0645d8841f51 125 int hit = 0;
bogdanm 13:0645d8841f51 126 uint16_t dlv;
bogdanm 13:0645d8841f51 127 uint8_t mv, dav;
bogdanm 13:0645d8841f51 128 if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
mbed_official 51:7838415c99e7 129 int err_best = baudrate, b;
mbed_official 51:7838415c99e7 130 for (mv = 1; mv < 16 && !hit; mv++)
mbed_official 51:7838415c99e7 131 {
mbed_official 51:7838415c99e7 132 for (dav = 0; dav < mv; dav++)
mbed_official 51:7838415c99e7 133 {
mbed_official 51:7838415c99e7 134 // baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
mbed_official 51:7838415c99e7 135 // solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
mbed_official 51:7838415c99e7 136 // mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
mbed_official 51:7838415c99e7 137 // for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
mbed_official 51:7838415c99e7 138 // note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
mbed_official 51:7838415c99e7 139
mbed_official 51:7838415c99e7 140 if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
mbed_official 51:7838415c99e7 141 dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
mbed_official 51:7838415c99e7 142 else // 2 bits headroom, use more precision
mbed_official 51:7838415c99e7 143 dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
mbed_official 51:7838415c99e7 144
mbed_official 51:7838415c99e7 145 // datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
mbed_official 51:7838415c99e7 146 if (dlv == 0)
mbed_official 51:7838415c99e7 147 dlv = 1;
mbed_official 51:7838415c99e7 148
mbed_official 51:7838415c99e7 149 // datasheet says if dav > 0 then DL must be >= 2
mbed_official 51:7838415c99e7 150 if ((dav > 0) && (dlv < 2))
mbed_official 51:7838415c99e7 151 dlv = 2;
mbed_official 51:7838415c99e7 152
mbed_official 51:7838415c99e7 153 // integer rearrangement of the baudrate equation (with rounding)
mbed_official 51:7838415c99e7 154 b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
mbed_official 51:7838415c99e7 155
mbed_official 51:7838415c99e7 156 // check to see how we went
mbed_official 51:7838415c99e7 157 b = abs(b - baudrate);
mbed_official 51:7838415c99e7 158 if (b < err_best)
mbed_official 51:7838415c99e7 159 {
mbed_official 51:7838415c99e7 160 err_best = b;
mbed_official 51:7838415c99e7 161
mbed_official 51:7838415c99e7 162 DL = dlv;
mbed_official 51:7838415c99e7 163 MulVal = mv;
mbed_official 51:7838415c99e7 164 DivAddVal = dav;
mbed_official 51:7838415c99e7 165
mbed_official 51:7838415c99e7 166 if (b == baudrate)
mbed_official 51:7838415c99e7 167 {
mbed_official 51:7838415c99e7 168 hit = 1;
mbed_official 51:7838415c99e7 169 break;
bogdanm 13:0645d8841f51 170 }
bogdanm 13:0645d8841f51 171 }
bogdanm 13:0645d8841f51 172 }
bogdanm 13:0645d8841f51 173 }
bogdanm 13:0645d8841f51 174 }
bogdanm 13:0645d8841f51 175
bogdanm 13:0645d8841f51 176 // set LCR[DLAB] to enable writing to divider registers
bogdanm 13:0645d8841f51 177 obj->uart->LCR |= (1 << 7);
bogdanm 13:0645d8841f51 178
bogdanm 13:0645d8841f51 179 // set divider values
bogdanm 13:0645d8841f51 180 obj->uart->DLM = (DL >> 8) & 0xFF;
bogdanm 13:0645d8841f51 181 obj->uart->DLL = (DL >> 0) & 0xFF;
bogdanm 13:0645d8841f51 182 obj->uart->FDR = (uint32_t) DivAddVal << 0
bogdanm 13:0645d8841f51 183 | (uint32_t) MulVal << 4;
bogdanm 13:0645d8841f51 184
bogdanm 13:0645d8841f51 185 // clear LCR[DLAB]
bogdanm 13:0645d8841f51 186 obj->uart->LCR &= ~(1 << 7);
bogdanm 13:0645d8841f51 187 }
bogdanm 13:0645d8841f51 188
bogdanm 13:0645d8841f51 189 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
bogdanm 13:0645d8841f51 190 // 0: 1 stop bits, 1: 2 stop bits
bogdanm 13:0645d8841f51 191 if (stop_bits != 1 && stop_bits != 2) {
bogdanm 13:0645d8841f51 192 error("Invalid stop bits specified");
bogdanm 13:0645d8841f51 193 }
bogdanm 13:0645d8841f51 194 stop_bits -= 1;
bogdanm 13:0645d8841f51 195
bogdanm 13:0645d8841f51 196 // 0: 5 data bits ... 3: 8 data bits
bogdanm 13:0645d8841f51 197 if (data_bits < 5 || data_bits > 8) {
bogdanm 13:0645d8841f51 198 error("Invalid number of bits (%d) in serial format, should be 5..8", data_bits);
bogdanm 13:0645d8841f51 199 }
bogdanm 13:0645d8841f51 200 data_bits -= 5;
bogdanm 13:0645d8841f51 201
bogdanm 13:0645d8841f51 202 int parity_enable, parity_select;
bogdanm 13:0645d8841f51 203 switch (parity) {
bogdanm 13:0645d8841f51 204 case ParityNone: parity_enable = 0; parity_select = 0; break;
bogdanm 13:0645d8841f51 205 case ParityOdd : parity_enable = 1; parity_select = 0; break;
bogdanm 13:0645d8841f51 206 case ParityEven: parity_enable = 1; parity_select = 1; break;
bogdanm 13:0645d8841f51 207 case ParityForced1: parity_enable = 1; parity_select = 2; break;
bogdanm 13:0645d8841f51 208 case ParityForced0: parity_enable = 1; parity_select = 3; break;
bogdanm 13:0645d8841f51 209 default:
bogdanm 13:0645d8841f51 210 error("Invalid serial parity setting");
bogdanm 13:0645d8841f51 211 return;
bogdanm 13:0645d8841f51 212 }
bogdanm 13:0645d8841f51 213
bogdanm 13:0645d8841f51 214 obj->uart->LCR = data_bits << 0
bogdanm 13:0645d8841f51 215 | stop_bits << 2
bogdanm 13:0645d8841f51 216 | parity_enable << 3
bogdanm 13:0645d8841f51 217 | parity_select << 4;
bogdanm 13:0645d8841f51 218 }
bogdanm 13:0645d8841f51 219
bogdanm 13:0645d8841f51 220 /******************************************************************************
bogdanm 13:0645d8841f51 221 * INTERRUPTS HANDLING
bogdanm 13:0645d8841f51 222 ******************************************************************************/
bogdanm 13:0645d8841f51 223 static inline void uart_irq(uint32_t iir, uint32_t index) {
bogdanm 13:0645d8841f51 224 // [Chapter 14] LPC17xx UART0/2/3: UARTn Interrupt Handling
bogdanm 13:0645d8841f51 225 SerialIrq irq_type;
bogdanm 13:0645d8841f51 226 switch (iir) {
bogdanm 13:0645d8841f51 227 case 1: irq_type = TxIrq; break;
bogdanm 13:0645d8841f51 228 case 2: irq_type = RxIrq; break;
bogdanm 13:0645d8841f51 229 default: return;
bogdanm 13:0645d8841f51 230 }
bogdanm 13:0645d8841f51 231
bogdanm 13:0645d8841f51 232 if (serial_irq_ids[index] != 0)
bogdanm 13:0645d8841f51 233 irq_handler(serial_irq_ids[index], irq_type);
bogdanm 13:0645d8841f51 234 }
bogdanm 13:0645d8841f51 235
bogdanm 13:0645d8841f51 236 void uart0_irq() {uart_irq((LPC_USART->IIR >> 1) & 0x7, 0);}
bogdanm 13:0645d8841f51 237
bogdanm 13:0645d8841f51 238 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
bogdanm 13:0645d8841f51 239 irq_handler = handler;
bogdanm 13:0645d8841f51 240 serial_irq_ids[obj->index] = id;
bogdanm 13:0645d8841f51 241 }
bogdanm 13:0645d8841f51 242
bogdanm 13:0645d8841f51 243 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
bogdanm 13:0645d8841f51 244 IRQn_Type irq_n = (IRQn_Type)0;
bogdanm 13:0645d8841f51 245 uint32_t vector = 0;
bogdanm 13:0645d8841f51 246 switch ((int)obj->uart) {
bogdanm 13:0645d8841f51 247 case UART_0: irq_n=UART_IRQn ; vector = (uint32_t)&uart0_irq; break;
bogdanm 13:0645d8841f51 248 }
bogdanm 13:0645d8841f51 249
bogdanm 13:0645d8841f51 250 if (enable) {
bogdanm 13:0645d8841f51 251 obj->uart->IER |= 1 << irq;
bogdanm 13:0645d8841f51 252 NVIC_SetVector(irq_n, vector);
bogdanm 13:0645d8841f51 253 NVIC_EnableIRQ(irq_n);
bogdanm 13:0645d8841f51 254 } else { // disable
bogdanm 13:0645d8841f51 255 int all_disabled = 0;
bogdanm 13:0645d8841f51 256 SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
bogdanm 13:0645d8841f51 257
bogdanm 13:0645d8841f51 258 obj->uart->IER &= ~(1 << irq);
bogdanm 13:0645d8841f51 259 all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
bogdanm 13:0645d8841f51 260
bogdanm 13:0645d8841f51 261 if (all_disabled)
bogdanm 13:0645d8841f51 262 NVIC_DisableIRQ(irq_n);
bogdanm 13:0645d8841f51 263 }
bogdanm 13:0645d8841f51 264 }
bogdanm 13:0645d8841f51 265
bogdanm 13:0645d8841f51 266 /******************************************************************************
bogdanm 13:0645d8841f51 267 * READ/WRITE
bogdanm 13:0645d8841f51 268 ******************************************************************************/
bogdanm 13:0645d8841f51 269 int serial_getc(serial_t *obj) {
bogdanm 13:0645d8841f51 270 while (!serial_readable(obj));
bogdanm 13:0645d8841f51 271 return obj->uart->RBR;
bogdanm 13:0645d8841f51 272 }
bogdanm 13:0645d8841f51 273
bogdanm 13:0645d8841f51 274 void serial_putc(serial_t *obj, int c) {
bogdanm 13:0645d8841f51 275 while (!serial_writable(obj));
bogdanm 13:0645d8841f51 276 obj->uart->THR = c;
bogdanm 13:0645d8841f51 277 }
bogdanm 13:0645d8841f51 278
bogdanm 13:0645d8841f51 279 int serial_readable(serial_t *obj) {
bogdanm 13:0645d8841f51 280 return obj->uart->LSR & 0x01;
bogdanm 13:0645d8841f51 281 }
bogdanm 13:0645d8841f51 282
bogdanm 13:0645d8841f51 283 int serial_writable(serial_t *obj) {
bogdanm 13:0645d8841f51 284 return obj->uart->LSR & 0x20;
bogdanm 13:0645d8841f51 285 }
bogdanm 13:0645d8841f51 286
bogdanm 13:0645d8841f51 287 void serial_clear(serial_t *obj) {
bogdanm 13:0645d8841f51 288 obj->uart->FCR = 1 << 1 // rx FIFO reset
bogdanm 13:0645d8841f51 289 | 1 << 2 // tx FIFO reset
bogdanm 13:0645d8841f51 290 | 0 << 6; // interrupt depth
bogdanm 13:0645d8841f51 291 }
bogdanm 13:0645d8841f51 292
bogdanm 13:0645d8841f51 293 void serial_pinout_tx(PinName tx) {
bogdanm 13:0645d8841f51 294 pinmap_pinout(tx, PinMap_UART_TX);
bogdanm 13:0645d8841f51 295 }
bogdanm 13:0645d8841f51 296
bogdanm 13:0645d8841f51 297 void serial_break_set(serial_t *obj) {
bogdanm 13:0645d8841f51 298 obj->uart->LCR |= (1 << 6);
bogdanm 13:0645d8841f51 299 }
bogdanm 13:0645d8841f51 300
bogdanm 13:0645d8841f51 301 void serial_break_clear(serial_t *obj) {
bogdanm 13:0645d8841f51 302 obj->uart->LCR &= ~(1 << 6);
bogdanm 13:0645d8841f51 303 }
bogdanm 13:0645d8841f51 304