1 /* mbed Microcontroller Library
2 * Copyright (c) 2006-2013 ARM Limited
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
16 #include "mbed_assert.h"
17 #include "serial_api.h"
19 // math.h required for floating point operations for baud rate calculation
26 #include "clk_freqs.h"
27 #include "PeripheralPins.h"
31 /******************************************************************************
33 ******************************************************************************/
35 static uint32_t serial_irq_ids[UART_NUM] = {0};
36 static uart_irq_handler irq_handler;
38 int stdio_uart_inited = 0;
41 static inline uint32_t serial_get_src_clock(serial_t *obj) {
44 switch ((int)obj->uart) {
46 mux = (SIM->SOPT2 & SIM_SOPT2_LPUART0SRC_MASK) >> SIM_SOPT2_LPUART0SRC_SHIFT;
49 mux = (SIM->SOPT2 & SIM_SOPT2_LPUART1SRC_MASK) >> SIM_SOPT2_LPUART1SRC_SHIFT;
51 case UART_2: /* TODO: add UART2 support */ break;
55 case 1: srcclk = fastirc_frequency(); break;
56 case 2: srcclk = extosc_frequency(); break;
57 case 3: srcclk = mcgirc_frequency(); break;
58 default: srcclk = 0; break;
64 void serial_init(serial_t *obj, PinName tx, PinName rx) {
65 // determine the UART to use
66 UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX);
67 UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX);
68 UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx);
69 MBED_ASSERT((int)uart != NC);
71 obj->uart = (LPUART_Type *)uart;
76 SIM->SOPT2 |= SIM_SOPT2_LPUART0SRC(1);
77 SIM->SCGC5 |= SIM_SCGC5_LPUART0_MASK;
80 SIM->SOPT2 |= SIM_SOPT2_LPUART1SRC(1);
81 SIM->SCGC5 |= SIM_SCGC5_LPUART1_MASK;
83 case UART_2: /* TODO: add UART2 support */ break;
86 // reset UART registers
87 obj->uart->BAUD = 0x0F000004;
88 obj->uart->STAT = 0xC01FC000;
89 obj->uart->CTRL = 0x00000000;
90 obj->uart->MATCH = 0x00000000;
93 case UART_0: obj->index = 0; break;
94 case UART_1: obj->index = 1; break;
95 case UART_2: /* TODO: add UART2 support */ break;
98 // set default baud rate and format
99 serial_baud (obj, 9600);
100 serial_format(obj, 8, ParityNone, 1);
102 // pinout the chosen uart
103 pinmap_pinout(tx, PinMap_UART_TX);
104 pinmap_pinout(rx, PinMap_UART_RX);
106 // set rx/tx pins in PullUp mode
107 if (tx != NC) pin_mode(tx, PullUp);
108 if (rx != NC) pin_mode(rx, PullUp);
110 obj->uart->CTRL |= (LPUART_CTRL_RE_MASK | LPUART_CTRL_TE_MASK);
112 if (uart == STDIO_UART) {
113 stdio_uart_inited = 1;
114 memcpy(&stdio_uart, obj, sizeof(serial_t));
118 void serial_free(serial_t *obj) {
119 serial_irq_ids[obj->index] = 0;
124 // set the baud rate, taking in to account the current SystemFrequency
125 void serial_baud(serial_t *obj, int baudrate) {
127 uint32_t i, sbr, sbrTemp, osr, temp, baud, baudDiff;
129 /* get value of serial source clock */
130 uint32_t PCLK = serial_get_src_clock(obj);
132 /* loop to find the best osr value possible, one that generates minimum baudDiff
133 * iterate through the rest of the supported values of osr */
135 for (i = 5; i <= 33; i++) {
136 /* calculate the temporary sbr value */
137 sbrTemp = PCLK / (baudrate * i);
139 /* calculate the baud rate based on the temporary osr and sbr values */
140 calcBaudrate = PCLK / (i * sbrTemp);
142 if (calcBaudrate > baudrate) {
143 baudDiff = calcBaudrate - baudrate;
145 baudDiff = baudrate - calcBaudrate;
148 if (baudDiff < temp) {
149 osr = i - 1; /* update and store the best osr value calculated */
150 sbr = sbrTemp; /* update store the best sbr value calculated */
153 break; /* end for loop if founded the best osr and sbr value */
162 temp = obj->uart->CTRL & (LPUART_CTRL_RE_MASK | LPUART_CTRL_TE_MASK);
164 /* disable UART before changing registers */
165 obj->uart->CTRL &= ~(LPUART_CTRL_RE_MASK | LPUART_CTRL_TE_MASK);
167 /* read BAUD register with clearing old baudrate settings into baud variable */
168 baud = obj->uart->BAUD & ~(LPUART_BAUD_SBR_MASK | LPUART_BAUD_OSR_MASK | LPUART_BAUD_BOTHEDGE_MASK);
170 /* write the new osr and sbr values */
171 baud |= (LPUART_BAUD_SBR(sbr) | LPUART_BAUD_OSR(osr));
173 /* Check if osr is between 4x and 7x oversampling.
174 * If so, then "BOTHEDGE" sampling must be turned on */
175 if ((osr > 3) && (osr < 8)) {
176 baud |= LPUART_BAUD_BOTHEDGE_MASK;
179 /* write new values into BAUD register */
180 obj->uart->BAUD = baud;
182 /* restore C2 state */
183 obj->uart->CTRL |= temp;
186 void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
187 MBED_ASSERT((stop_bits == 1) || (stop_bits == 2));
188 MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven));
189 MBED_ASSERT(data_bits == 8); // TODO: Support other number of data bits (also in the write method!)
192 uint32_t c2_state = obj->uart->CTRL & (LPUART_CTRL_RE_MASK | LPUART_CTRL_TE_MASK);
194 // disable UART before changing registers
195 obj->uart->CTRL &= ~(LPUART_CTRL_RE_MASK | LPUART_CTRL_TE_MASK);
198 uint8_t parity_enable = 0, parity_select = 0;
200 case ParityNone: parity_enable = 0; parity_select = 0; break;
201 case ParityOdd : parity_enable = 1; parity_select = 1; data_bits++; break;
202 case ParityEven: parity_enable = 1; parity_select = 0; data_bits++; break;
209 // data bits, parity and parity mode
210 obj->uart->CTRL = ((parity_enable << 1) | (parity_select << 0));
213 obj->uart->BAUD &= ~LPUART_BAUD_SBNS_MASK;
214 obj->uart->BAUD |= (stop_bits << LPUART_BAUD_SBNS_SHIFT);
217 obj->uart->CTRL |= c2_state;
220 /******************************************************************************
221 * INTERRUPTS HANDLING
222 ******************************************************************************/
223 static inline void uart_irq(uint32_t status, uint32_t index) {
224 if (serial_irq_ids[index] != 0) {
225 if (status & LPUART_STAT_TDRE_MASK)
226 irq_handler(serial_irq_ids[index], TxIrq);
228 if (status & LPUART_STAT_RDRF_MASK)
229 irq_handler(serial_irq_ids[index], RxIrq);
233 void uart0_irq() {uart_irq(LPUART0->STAT, 0);}
234 void uart1_irq() {uart_irq(LPUART1->STAT, 1);}
236 void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
237 irq_handler = handler;
238 serial_irq_ids[obj->index] = id;
241 void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
242 IRQn_Type irq_n = (IRQn_Type)0;
244 switch ((int)obj->uart) {
245 case UART_0: irq_n=LPUART0_IRQn; vector = (uint32_t)&uart0_irq; break;
246 case UART_1: irq_n=LPUART1_IRQn; vector = (uint32_t)&uart1_irq; break;
251 case RxIrq: obj->uart->CTRL |= LPUART_CTRL_RIE_MASK; break;
252 case TxIrq: obj->uart->CTRL |= LPUART_CTRL_TIE_MASK; break;
254 NVIC_SetVector(irq_n, vector);
255 NVIC_EnableIRQ(irq_n);
258 int all_disabled = 0;
259 SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
261 case RxIrq: obj->uart->CTRL &= ~(LPUART_CTRL_RIE_MASK); break;
262 case TxIrq: obj->uart->CTRL &= ~(LPUART_CTRL_TIE_MASK); break;
265 case RxIrq: all_disabled = (obj->uart->CTRL & LPUART_CTRL_RIE_MASK) == 0; break;
266 case TxIrq: all_disabled = (obj->uart->CTRL & LPUART_CTRL_TIE_MASK) == 0; break;
269 NVIC_DisableIRQ(irq_n);
273 /******************************************************************************
275 ******************************************************************************/
276 int serial_getc(serial_t *obj) {
277 while (!serial_readable(obj));
278 return (obj->uart->DATA & 0xFFu);
281 void serial_putc(serial_t *obj, int c) {
282 while (!serial_writable(obj));
286 int serial_readable(serial_t *obj) {
288 if (obj->uart->STAT & LPUART_STAT_OR_MASK) {
289 obj->uart->STAT |= LPUART_STAT_OR_MASK;
291 return (obj->uart->STAT & LPUART_STAT_RDRF_MASK);
294 int serial_writable(serial_t *obj) {
296 if (obj->uart->STAT & LPUART_STAT_OR_MASK) {
297 obj->uart->STAT |= LPUART_STAT_OR_MASK;
299 return (obj->uart->STAT & LPUART_STAT_TDRE_MASK);
302 void serial_clear(serial_t *obj) {
305 void serial_pinout_tx(PinName tx) {
306 pinmap_pinout(tx, PinMap_UART_TX);
309 void serial_break_set(serial_t *obj) {
310 obj->uart->CTRL |= LPUART_CTRL_SBK_MASK;
313 void serial_break_clear(serial_t *obj) {
314 obj->uart->CTRL &= ~LPUART_CTRL_SBK_MASK;