fix for mbed lib issue 3 (i2c problem) see also https://mbed.org/users/mbed_official/code/mbed/issues/3 affected implementations: LPC812, LPC11U24, LPC1768, LPC2368, LPC4088
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serial_api.c
00001 /* mbed Microcontroller Library 00002 * Copyright (c) 2006-2013 ARM Limited 00003 * 00004 * Licensed under the Apache License, Version 2.0 (the "License"); 00005 * you may not use this file except in compliance with the License. 00006 * You may obtain a copy of the License at 00007 * 00008 * http://www.apache.org/licenses/LICENSE-2.0 00009 * 00010 * Unless required by applicable law or agreed to in writing, software 00011 * distributed under the License is distributed on an "AS IS" BASIS, 00012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00013 * See the License for the specific language governing permissions and 00014 * limitations under the License. 00015 */ 00016 // math.h required for floating point operations for baud rate calculation 00017 #include <math.h> 00018 #include <string.h> 00019 00020 #include "serial_api.h" 00021 #include "cmsis.h" 00022 #include "pinmap.h" 00023 #include "error.h" 00024 00025 /****************************************************************************** 00026 * INITIALIZATION 00027 ******************************************************************************/ 00028 #define UART_NUM 4 00029 00030 static const PinMap PinMap_UART_TX[] = { 00031 {P0_0, UART_3, 2}, 00032 {P0_2, UART_0, 1}, 00033 {P0_10, UART_2, 1}, 00034 {P0_15, UART_1, 1}, 00035 {P0_25, UART_3, 3}, 00036 {P2_0 , UART_1, 2}, 00037 {P2_8 , UART_2, 2}, 00038 {P4_28, UART_3, 3}, 00039 {NC , NC , 0} 00040 }; 00041 00042 static const PinMap PinMap_UART_RX[] = { 00043 {P0_1 , UART_3, 2}, 00044 {P0_3 , UART_0, 1}, 00045 {P0_11, UART_2, 1}, 00046 {P0_16, UART_1, 1}, 00047 {P0_26, UART_3, 3}, 00048 {P2_1 , UART_1, 2}, 00049 {P2_9 , UART_2, 2}, 00050 {P4_29, UART_3, 3}, 00051 {NC , NC , 0} 00052 }; 00053 00054 static uint32_t serial_irq_ids[UART_NUM] = {0}; 00055 static uart_irq_handler irq_handler; 00056 00057 int stdio_uart_inited = 0; 00058 serial_t stdio_uart; 00059 00060 void serial_init(serial_t *obj, PinName tx, PinName rx) { 00061 int is_stdio_uart = 0; 00062 00063 // determine the UART to use 00064 UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX); 00065 UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX); 00066 UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx); 00067 if ((int)uart == NC) { 00068 error("Serial pinout mapping failed"); 00069 } 00070 00071 obj->uart = (LPC_UART_TypeDef *)uart; 00072 // enable power 00073 switch (uart) { 00074 case UART_0: LPC_SC->PCONP |= 1 << 3; break; 00075 case UART_1: LPC_SC->PCONP |= 1 << 4; break; 00076 case UART_2: LPC_SC->PCONP |= 1 << 24; break; 00077 case UART_3: LPC_SC->PCONP |= 1 << 25; break; 00078 } 00079 00080 // enable fifos and default rx trigger level 00081 obj->uart->FCR = 1 << 0 // FIFO Enable - 0 = Disables, 1 = Enabled 00082 | 0 << 1 // Rx Fifo Reset 00083 | 0 << 2 // Tx Fifo Reset 00084 | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars 00085 00086 // disable irqs 00087 obj->uart->IER = 0 << 0 // Rx Data available irq enable 00088 | 0 << 1 // Tx Fifo empty irq enable 00089 | 0 << 2; // Rx Line Status irq enable 00090 00091 // set default baud rate and format 00092 serial_baud (obj, 9600); 00093 serial_format(obj, 8, ParityNone, 1); 00094 00095 // pinout the chosen uart 00096 pinmap_pinout(tx, PinMap_UART_TX); 00097 pinmap_pinout(rx, PinMap_UART_RX); 00098 00099 // set rx/tx pins in PullUp mode 00100 pin_mode(tx, PullUp); 00101 pin_mode(rx, PullUp); 00102 00103 switch (uart) { 00104 case UART_0: obj->index = 0; break; 00105 case UART_1: obj->index = 1; break; 00106 case UART_2: obj->index = 2; break; 00107 case UART_3: obj->index = 3; break; 00108 } 00109 00110 is_stdio_uart = (uart == STDIO_UART) ? (1) : (0); 00111 00112 if (is_stdio_uart) { 00113 stdio_uart_inited = 1; 00114 memcpy(&stdio_uart, obj, sizeof(serial_t)); 00115 } 00116 } 00117 00118 void serial_free(serial_t *obj) { 00119 serial_irq_ids[obj->index] = 0; 00120 } 00121 00122 // serial_baud 00123 // set the baud rate, taking in to account the current SystemFrequency 00124 void serial_baud(serial_t *obj, int baudrate) { 00125 // The LPC2300 and LPC1700 have a divider and a fractional divider to control the 00126 // baud rate. The formula is: 00127 // 00128 // Baudrate = (1 / PCLK) * 16 * DL * (1 + DivAddVal / MulVal) 00129 // where: 00130 // 1 < MulVal <= 15 00131 // 0 <= DivAddVal < 14 00132 // DivAddVal < MulVal 00133 // 00134 // set pclk to /1 00135 switch ((int)obj->uart) { 00136 case UART_0: LPC_SC->PCLKSEL0 &= ~(0x3 << 6); LPC_SC->PCLKSEL0 |= (0x1 << 6); break; 00137 case UART_1: LPC_SC->PCLKSEL0 &= ~(0x3 << 8); LPC_SC->PCLKSEL0 |= (0x1 << 8); break; 00138 case UART_2: LPC_SC->PCLKSEL1 &= ~(0x3 << 16); LPC_SC->PCLKSEL1 |= (0x1 << 16); break; 00139 case UART_3: LPC_SC->PCLKSEL1 &= ~(0x3 << 18); LPC_SC->PCLKSEL1 |= (0x1 << 18); break; 00140 default: error("serial_baud"); break; 00141 } 00142 00143 uint32_t PCLK = SystemCoreClock; 00144 00145 // First we check to see if the basic divide with no DivAddVal/MulVal 00146 // ratio gives us an integer result. If it does, we set DivAddVal = 0, 00147 // MulVal = 1. Otherwise, we search the valid ratio value range to find 00148 // the closest match. This could be more elegant, using search methods 00149 // and/or lookup tables, but the brute force method is not that much 00150 // slower, and is more maintainable. 00151 uint16_t DL = PCLK / (16 * baudrate); 00152 00153 uint8_t DivAddVal = 0; 00154 uint8_t MulVal = 1; 00155 int hit = 0; 00156 uint16_t dlv; 00157 uint8_t mv, dav; 00158 if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder 00159 float err_best = (float) baudrate; 00160 uint16_t dlmax = DL; 00161 for ( dlv = (dlmax/2); (dlv <= dlmax) && !hit; dlv++) { 00162 for ( mv = 1; mv <= 15; mv++) { 00163 for ( dav = 1; dav < mv; dav++) { 00164 float ratio = 1.0f + ((float) dav / (float) mv); 00165 float calcbaud = (float)PCLK / (16.0f * (float) dlv * ratio); 00166 float err = fabs(((float) baudrate - calcbaud) / (float) baudrate); 00167 if (err < err_best) { 00168 DL = dlv; 00169 DivAddVal = dav; 00170 MulVal = mv; 00171 err_best = err; 00172 if (err < 0.001f) { 00173 hit = 1; 00174 } 00175 } 00176 } 00177 } 00178 } 00179 } 00180 00181 // set LCR[DLAB] to enable writing to divider registers 00182 obj->uart->LCR |= (1 << 7); 00183 00184 // set divider values 00185 obj->uart->DLM = (DL >> 8) & 0xFF; 00186 obj->uart->DLL = (DL >> 0) & 0xFF; 00187 obj->uart->FDR = (uint32_t) DivAddVal << 0 00188 | (uint32_t) MulVal << 4; 00189 00190 // clear LCR[DLAB] 00191 obj->uart->LCR &= ~(1 << 7); 00192 } 00193 00194 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) { 00195 // 0: 1 stop bits, 1: 2 stop bits 00196 if (stop_bits != 1 && stop_bits != 2) { 00197 error("Invalid stop bits specified"); 00198 } 00199 stop_bits -= 1; 00200 00201 // 0: 5 data bits ... 3: 8 data bits 00202 if (data_bits < 5 || data_bits > 8) { 00203 error("Invalid number of bits (%d) in serial format, should be 5..8", data_bits); 00204 } 00205 data_bits -= 5; 00206 00207 int parity_enable, parity_select; 00208 switch (parity) { 00209 case ParityNone: parity_enable = 0; parity_select = 0; break; 00210 case ParityOdd : parity_enable = 1; parity_select = 0; break; 00211 case ParityEven: parity_enable = 1; parity_select = 1; break; 00212 case ParityForced1: parity_enable = 1; parity_select = 2; break; 00213 case ParityForced0: parity_enable = 1; parity_select = 3; break; 00214 default: 00215 error("Invalid serial parity setting"); 00216 return; 00217 } 00218 00219 obj->uart->LCR = data_bits << 0 00220 | stop_bits << 2 00221 | parity_enable << 3 00222 | parity_select << 4; 00223 } 00224 00225 /****************************************************************************** 00226 * INTERRUPTS HANDLING 00227 ******************************************************************************/ 00228 static inline void uart_irq(uint32_t iir, uint32_t index) { 00229 // [Chapter 14] LPC17xx UART0/2/3: UARTn Interrupt Handling 00230 SerialIrq irq_type; 00231 switch (iir) { 00232 case 1: irq_type = TxIrq; break; 00233 case 2: irq_type = RxIrq; break; 00234 default: return; 00235 } 00236 00237 if (serial_irq_ids[index] != 0) 00238 irq_handler(serial_irq_ids[index], irq_type); 00239 } 00240 00241 void uart0_irq() {uart_irq((LPC_UART0->IIR >> 1) & 0x7, 0);} 00242 void uart1_irq() {uart_irq((LPC_UART1->IIR >> 1) & 0x7, 1);} 00243 void uart2_irq() {uart_irq((LPC_UART2->IIR >> 1) & 0x7, 2);} 00244 void uart3_irq() {uart_irq((LPC_UART3->IIR >> 1) & 0x7, 3);} 00245 00246 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) { 00247 irq_handler = handler; 00248 serial_irq_ids[obj->index] = id; 00249 } 00250 00251 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) { 00252 IRQn_Type irq_n = (IRQn_Type )0; 00253 uint32_t vector = 0; 00254 switch ((int)obj->uart) { 00255 case UART_0: irq_n=UART0_IRQn; vector = (uint32_t)&uart0_irq; break; 00256 case UART_1: irq_n=UART1_IRQn; vector = (uint32_t)&uart1_irq; break; 00257 case UART_2: irq_n=UART2_IRQn; vector = (uint32_t)&uart2_irq; break; 00258 case UART_3: irq_n=UART3_IRQn ; vector = (uint32_t)&uart3_irq; break; 00259 } 00260 00261 if (enable) { 00262 obj->uart->IER |= 1 << irq; 00263 NVIC_SetVector(irq_n, vector); 00264 NVIC_EnableIRQ(irq_n); 00265 } else { // disable 00266 int all_disabled = 0; 00267 SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq); 00268 obj->uart->IER &= ~(1 << irq); 00269 all_disabled = (obj->uart->IER & (1 << other_irq)) == 0; 00270 if (all_disabled) 00271 NVIC_DisableIRQ(irq_n); 00272 } 00273 } 00274 00275 /****************************************************************************** 00276 * READ/WRITE 00277 ******************************************************************************/ 00278 int serial_getc(serial_t *obj) { 00279 while (!serial_readable(obj)); 00280 return obj->uart->RBR; 00281 } 00282 00283 void serial_putc(serial_t *obj, int c) { 00284 while (!serial_writable(obj)); 00285 obj->uart->THR = c; 00286 00287 uint32_t lsr = obj->uart->LSR; 00288 lsr = lsr; 00289 uint32_t thr = obj->uart->THR; 00290 thr = thr; 00291 } 00292 00293 int serial_readable(serial_t *obj) { 00294 return obj->uart->LSR & 0x01; 00295 } 00296 00297 int serial_writable(serial_t *obj) { 00298 return obj->uart->LSR & 0x20; 00299 } 00300 00301 void serial_clear(serial_t *obj) { 00302 obj->uart->FCR = 1 << 1 // rx FIFO reset 00303 | 1 << 2 // tx FIFO reset 00304 | 0 << 6; // interrupt depth 00305 } 00306 00307 void serial_pinout_tx(PinName tx) { 00308 pinmap_pinout(tx, PinMap_UART_TX); 00309 }
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