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Last commit 20 Feb 2019 by mbed official

targets/hal/TARGET_NXP/TARGET_LPC11UXX/serial_api.c@20:4263a77256ae, 2013-09-10 (annotated)

Committer:
bogdanm
Date:
Tue Sep 10 15:14:19 2013 +0300
Revision:
20:4263a77256ae
Parent:
13:0645d8841f51
Child:
51:7838415c99e7
Sync with git revision 171dda705c947bf910926a0b73d6a4797802554d

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
bogdanm 13:0645d8841f51 66 pin_function(USBTX, 0);
bogdanm 13:0645d8841f51 67 pin_function(USBRX, 0);
bogdanm 13:0645d8841f51 68
bogdanm 13:0645d8841f51 69 // enable fifos and default rx trigger level
bogdanm 13:0645d8841f51 70 obj->uart->FCR = 1 << 0 // FIFO Enable - 0 = Disables, 1 = Enabled
bogdanm 13:0645d8841f51 71 | 0 << 1 // Rx Fifo Reset
bogdanm 13:0645d8841f51 72 | 0 << 2 // Tx Fifo Reset
bogdanm 13:0645d8841f51 73 | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars
bogdanm 13:0645d8841f51 74
bogdanm 13:0645d8841f51 75 // disable irqs
bogdanm 13:0645d8841f51 76 obj->uart->IER = 0 << 0 // Rx Data available irq enable
bogdanm 13:0645d8841f51 77 | 0 << 1 // Tx Fifo empty irq enable
bogdanm 13:0645d8841f51 78 | 0 << 2; // Rx Line Status irq enable
bogdanm 13:0645d8841f51 79
bogdanm 13:0645d8841f51 80 // set default baud rate and format
bogdanm 13:0645d8841f51 81 serial_baud (obj, 9600);
bogdanm 13:0645d8841f51 82 serial_format(obj, 8, ParityNone, 1);
bogdanm 13:0645d8841f51 83
bogdanm 13:0645d8841f51 84 // pinout the chosen uart
bogdanm 13:0645d8841f51 85 pinmap_pinout(tx, PinMap_UART_TX);
bogdanm 13:0645d8841f51 86 pinmap_pinout(rx, PinMap_UART_RX);
bogdanm 13:0645d8841f51 87
bogdanm 13:0645d8841f51 88 // set rx/tx pins in PullUp mode
bogdanm 13:0645d8841f51 89 pin_mode(tx, PullUp);
bogdanm 13:0645d8841f51 90 pin_mode(rx, PullUp);
bogdanm 13:0645d8841f51 91
bogdanm 13:0645d8841f51 92 switch (uart) {
bogdanm 13:0645d8841f51 93 case UART_0: obj->index = 0; break;
bogdanm 13:0645d8841f51 94 }
bogdanm 13:0645d8841f51 95
bogdanm 13:0645d8841f51 96 is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
bogdanm 13:0645d8841f51 97
bogdanm 13:0645d8841f51 98 if (is_stdio_uart) {
bogdanm 13:0645d8841f51 99 stdio_uart_inited = 1;
bogdanm 13:0645d8841f51 100 memcpy(&stdio_uart, obj, sizeof(serial_t));
bogdanm 13:0645d8841f51 101 }
bogdanm 13:0645d8841f51 102 }
bogdanm 13:0645d8841f51 103
bogdanm 13:0645d8841f51 104 void serial_free(serial_t *obj) {
bogdanm 13:0645d8841f51 105 serial_irq_ids[obj->index] = 0;
bogdanm 13:0645d8841f51 106 }
bogdanm 13:0645d8841f51 107
bogdanm 13:0645d8841f51 108 // serial_baud
bogdanm 13:0645d8841f51 109 // set the baud rate, taking in to account the current SystemFrequency
bogdanm 13:0645d8841f51 110 void serial_baud(serial_t *obj, int baudrate) {
bogdanm 13:0645d8841f51 111 LPC_SYSCON->UARTCLKDIV = 0x1;
bogdanm 13:0645d8841f51 112 uint32_t PCLK = SystemCoreClock;
bogdanm 13:0645d8841f51 113 // First we check to see if the basic divide with no DivAddVal/MulVal
bogdanm 13:0645d8841f51 114 // ratio gives us an integer result. If it does, we set DivAddVal = 0,
bogdanm 13:0645d8841f51 115 // MulVal = 1. Otherwise, we search the valid ratio value range to find
bogdanm 13:0645d8841f51 116 // the closest match. This could be more elegant, using search methods
bogdanm 13:0645d8841f51 117 // and/or lookup tables, but the brute force method is not that much
bogdanm 13:0645d8841f51 118 // slower, and is more maintainable.
bogdanm 13:0645d8841f51 119 uint16_t DL = PCLK / (16 * baudrate);
bogdanm 13:0645d8841f51 120
bogdanm 13:0645d8841f51 121 uint8_t DivAddVal = 0;
bogdanm 13:0645d8841f51 122 uint8_t MulVal = 1;
bogdanm 13:0645d8841f51 123 int hit = 0;
bogdanm 13:0645d8841f51 124 uint16_t dlv;
bogdanm 13:0645d8841f51 125 uint8_t mv, dav;
bogdanm 13:0645d8841f51 126 if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder
bogdanm 13:0645d8841f51 127 float err_best = (float) baudrate;
bogdanm 13:0645d8841f51 128 uint16_t dlmax = DL;
bogdanm 13:0645d8841f51 129 for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) {
bogdanm 13:0645d8841f51 130 for ( mv = 1; mv <= 15; mv++) {
bogdanm 13:0645d8841f51 131 for ( dav = 1; dav < mv; dav++) {
bogdanm 13:0645d8841f51 132 float ratio = 1.0f + ((float) dav / (float) mv);
bogdanm 13:0645d8841f51 133 float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio);
bogdanm 13:0645d8841f51 134 float err = fabs(((float) baudrate - calcbaud) / (float) baudrate);
bogdanm 13:0645d8841f51 135 if (err < err_best) {
bogdanm 13:0645d8841f51 136 DL = dlv;
bogdanm 13:0645d8841f51 137 DivAddVal = dav;
bogdanm 13:0645d8841f51 138 MulVal = mv;
bogdanm 13:0645d8841f51 139 err_best = err;
bogdanm 13:0645d8841f51 140 if (err < 0.001f) {
bogdanm 13:0645d8841f51 141 hit = 1;
bogdanm 13:0645d8841f51 142 }
bogdanm 13:0645d8841f51 143 }
bogdanm 13:0645d8841f51 144 }
bogdanm 13:0645d8841f51 145 }
bogdanm 13:0645d8841f51 146 }
bogdanm 13:0645d8841f51 147 }
bogdanm 13:0645d8841f51 148
bogdanm 13:0645d8841f51 149 // set LCR[DLAB] to enable writing to divider registers
bogdanm 13:0645d8841f51 150 obj->uart->LCR |= (1 << 7);
bogdanm 13:0645d8841f51 151
bogdanm 13:0645d8841f51 152 // set divider values
bogdanm 13:0645d8841f51 153 obj->uart->DLM = (DL >> 8) & 0xFF;
bogdanm 13:0645d8841f51 154 obj->uart->DLL = (DL >> 0) & 0xFF;
bogdanm 13:0645d8841f51 155 obj->uart->FDR = (uint32_t) DivAddVal << 0
bogdanm 13:0645d8841f51 156 | (uint32_t) MulVal << 4;
bogdanm 13:0645d8841f51 157
bogdanm 13:0645d8841f51 158 // clear LCR[DLAB]
bogdanm 13:0645d8841f51 159 obj->uart->LCR &= ~(1 << 7);
bogdanm 13:0645d8841f51 160 }
bogdanm 13:0645d8841f51 161
bogdanm 13:0645d8841f51 162 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
bogdanm 13:0645d8841f51 163 // 0: 1 stop bits, 1: 2 stop bits
bogdanm 13:0645d8841f51 164 if (stop_bits != 1 && stop_bits != 2) {
bogdanm 13:0645d8841f51 165 error("Invalid stop bits specified");
bogdanm 13:0645d8841f51 166 }
bogdanm 13:0645d8841f51 167 stop_bits -= 1;
bogdanm 13:0645d8841f51 168
bogdanm 13:0645d8841f51 169 // 0: 5 data bits ... 3: 8 data bits
bogdanm 13:0645d8841f51 170 if (data_bits < 5 || data_bits > 8) {
bogdanm 13:0645d8841f51 171 error("Invalid number of bits (%d) in serial format, should be 5..8", data_bits);
bogdanm 13:0645d8841f51 172 }
bogdanm 13:0645d8841f51 173 data_bits -= 5;
bogdanm 13:0645d8841f51 174
bogdanm 13:0645d8841f51 175 int parity_enable, parity_select;
bogdanm 13:0645d8841f51 176 switch (parity) {
bogdanm 13:0645d8841f51 177 case ParityNone: parity_enable = 0; parity_select = 0; break;
bogdanm 13:0645d8841f51 178 case ParityOdd : parity_enable = 1; parity_select = 0; break;
bogdanm 13:0645d8841f51 179 case ParityEven: parity_enable = 1; parity_select = 1; break;
bogdanm 13:0645d8841f51 180 case ParityForced1: parity_enable = 1; parity_select = 2; break;
bogdanm 13:0645d8841f51 181 case ParityForced0: parity_enable = 1; parity_select = 3; break;
bogdanm 13:0645d8841f51 182 default:
bogdanm 13:0645d8841f51 183 error("Invalid serial parity setting");
bogdanm 13:0645d8841f51 184 return;
bogdanm 13:0645d8841f51 185 }
bogdanm 13:0645d8841f51 186
bogdanm 13:0645d8841f51 187 obj->uart->LCR = data_bits << 0
bogdanm 13:0645d8841f51 188 | stop_bits << 2
bogdanm 13:0645d8841f51 189 | parity_enable << 3
bogdanm 13:0645d8841f51 190 | parity_select << 4;
bogdanm 13:0645d8841f51 191 }
bogdanm 13:0645d8841f51 192
bogdanm 13:0645d8841f51 193 /******************************************************************************
bogdanm 13:0645d8841f51 194 * INTERRUPTS HANDLING
bogdanm 13:0645d8841f51 195 ******************************************************************************/
bogdanm 13:0645d8841f51 196 static inline void uart_irq(uint32_t iir, uint32_t index) {
bogdanm 13:0645d8841f51 197 // [Chapter 14] LPC17xx UART0/2/3: UARTn Interrupt Handling
bogdanm 13:0645d8841f51 198 SerialIrq irq_type;
bogdanm 13:0645d8841f51 199 switch (iir) {
bogdanm 13:0645d8841f51 200 case 1: irq_type = TxIrq; break;
bogdanm 13:0645d8841f51 201 case 2: irq_type = RxIrq; break;
bogdanm 13:0645d8841f51 202 default: return;
bogdanm 13:0645d8841f51 203 }
bogdanm 13:0645d8841f51 204
bogdanm 13:0645d8841f51 205 if (serial_irq_ids[index] != 0)
bogdanm 13:0645d8841f51 206 irq_handler(serial_irq_ids[index], irq_type);
bogdanm 13:0645d8841f51 207 }
bogdanm 13:0645d8841f51 208
bogdanm 13:0645d8841f51 209 void uart0_irq() {uart_irq((LPC_USART->IIR >> 1) & 0x7, 0);}
bogdanm 13:0645d8841f51 210
bogdanm 13:0645d8841f51 211 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
bogdanm 13:0645d8841f51 212 irq_handler = handler;
bogdanm 13:0645d8841f51 213 serial_irq_ids[obj->index] = id;
bogdanm 13:0645d8841f51 214 }
bogdanm 13:0645d8841f51 215
bogdanm 13:0645d8841f51 216 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
bogdanm 13:0645d8841f51 217 IRQn_Type irq_n = (IRQn_Type)0;
bogdanm 13:0645d8841f51 218 uint32_t vector = 0;
bogdanm 13:0645d8841f51 219 switch ((int)obj->uart) {
bogdanm 13:0645d8841f51 220 case UART_0: irq_n=UART_IRQn ; vector = (uint32_t)&uart0_irq; break;
bogdanm 13:0645d8841f51 221 }
bogdanm 13:0645d8841f51 222
bogdanm 13:0645d8841f51 223 if (enable) {
bogdanm 13:0645d8841f51 224 obj->uart->IER |= 1 << irq;
bogdanm 13:0645d8841f51 225 NVIC_SetVector(irq_n, vector);
bogdanm 13:0645d8841f51 226 NVIC_EnableIRQ(irq_n);
bogdanm 13:0645d8841f51 227 } else { // disable
bogdanm 13:0645d8841f51 228 int all_disabled = 0;
bogdanm 13:0645d8841f51 229 SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
bogdanm 13:0645d8841f51 230
bogdanm 13:0645d8841f51 231 obj->uart->IER &= ~(1 << irq);
bogdanm 13:0645d8841f51 232 all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
bogdanm 13:0645d8841f51 233
bogdanm 13:0645d8841f51 234 if (all_disabled)
bogdanm 13:0645d8841f51 235 NVIC_DisableIRQ(irq_n);
bogdanm 13:0645d8841f51 236 }
bogdanm 13:0645d8841f51 237 }
bogdanm 13:0645d8841f51 238
bogdanm 13:0645d8841f51 239 /******************************************************************************
bogdanm 13:0645d8841f51 240 * READ/WRITE
bogdanm 13:0645d8841f51 241 ******************************************************************************/
bogdanm 13:0645d8841f51 242 int serial_getc(serial_t *obj) {
bogdanm 13:0645d8841f51 243 while (!serial_readable(obj));
bogdanm 13:0645d8841f51 244 return obj->uart->RBR;
bogdanm 13:0645d8841f51 245 }
bogdanm 13:0645d8841f51 246
bogdanm 13:0645d8841f51 247 void serial_putc(serial_t *obj, int c) {
bogdanm 13:0645d8841f51 248 while (!serial_writable(obj));
bogdanm 13:0645d8841f51 249 obj->uart->THR = c;
bogdanm 13:0645d8841f51 250 }
bogdanm 13:0645d8841f51 251
bogdanm 13:0645d8841f51 252 int serial_readable(serial_t *obj) {
bogdanm 13:0645d8841f51 253 return obj->uart->LSR & 0x01;
bogdanm 13:0645d8841f51 254 }
bogdanm 13:0645d8841f51 255
bogdanm 13:0645d8841f51 256 int serial_writable(serial_t *obj) {
bogdanm 13:0645d8841f51 257 return obj->uart->LSR & 0x20;
bogdanm 13:0645d8841f51 258 }
bogdanm 13:0645d8841f51 259
bogdanm 13:0645d8841f51 260 void serial_clear(serial_t *obj) {
bogdanm 13:0645d8841f51 261 obj->uart->FCR = 1 << 1 // rx FIFO reset
bogdanm 13:0645d8841f51 262 | 1 << 2 // tx FIFO reset
bogdanm 13:0645d8841f51 263 | 0 << 6; // interrupt depth
bogdanm 13:0645d8841f51 264 }
bogdanm 13:0645d8841f51 265
bogdanm 13:0645d8841f51 266 void serial_pinout_tx(PinName tx) {
bogdanm 13:0645d8841f51 267 pinmap_pinout(tx, PinMap_UART_TX);
bogdanm 13:0645d8841f51 268 }
bogdanm 13:0645d8841f51 269
bogdanm 13:0645d8841f51 270 void serial_break_set(serial_t *obj) {
bogdanm 13:0645d8841f51 271 obj->uart->LCR |= (1 << 6);
bogdanm 13:0645d8841f51 272 }
bogdanm 13:0645d8841f51 273
bogdanm 13:0645d8841f51 274 void serial_break_clear(serial_t *obj) {
bogdanm 13:0645d8841f51 275 obj->uart->LCR &= ~(1 << 6);
bogdanm 13:0645d8841f51 276 }
bogdanm 13:0645d8841f51 277