mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
targets/hal/TARGET_NXP/TARGET_LPC11UXX/serial_api.c
- Committer:
- janekm
- Date:
- 2014-09-16
- Revision:
- 310:6188e0254baa
- Parent:
- 274:6937b19af361
File content as of revision 310:6188e0254baa:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // math.h required for floating point operations for baud rate calculation #include <math.h> #include <string.h> #include <stdlib.h> #include "serial_api.h" #include "cmsis.h" #include "pinmap.h" #include "PeripheralPins.h" // For the Peripheral to Pin Definitions found in the individual Target's Platform /****************************************************************************** * INITIALIZATION ******************************************************************************/ #define UART_NUM 1 static uint32_t serial_irq_ids[UART_NUM] = {0}; static uart_irq_handler irq_handler; int stdio_uart_inited = 0; serial_t stdio_uart; void serial_init(serial_t *obj, PinName tx, PinName rx) { int is_stdio_uart = 0; // determine the UART to use UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX); UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX); UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx); MBED_ASSERT((int)uart != NC); obj->uart = (LPC_USART_Type *)uart; LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12); // [TODO] Consider more elegant approach // disconnect USBTX/RX mapping mux, for case when switching ports #ifdef USBTX pin_function(USBTX, 0); pin_function(USBRX, 0); #endif // enable fifos and default rx trigger level obj->uart->FCR = 1 << 0 // FIFO Enable - 0 = Disables, 1 = Enabled | 0 << 1 // Rx Fifo Reset | 0 << 2 // Tx Fifo Reset | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars // disable irqs obj->uart->IER = 0 << 0 // Rx Data available irq enable | 0 << 1 // Tx Fifo empty irq enable | 0 << 2; // Rx Line Status irq enable // set default baud rate and format serial_baud (obj, 9600); serial_format(obj, 8, ParityNone, 1); // pinout the chosen uart pinmap_pinout(tx, PinMap_UART_TX); pinmap_pinout(rx, PinMap_UART_RX); // set rx/tx pins in PullUp mode pin_mode(tx, PullUp); pin_mode(rx, PullUp); switch (uart) { case UART_0: obj->index = 0; break; } is_stdio_uart = (uart == STDIO_UART) ? (1) : (0); if (is_stdio_uart) { stdio_uart_inited = 1; memcpy(&stdio_uart, obj, sizeof(serial_t)); } } void serial_free(serial_t *obj) { serial_irq_ids[obj->index] = 0; } // serial_baud // set the baud rate, taking in to account the current SystemFrequency void serial_baud(serial_t *obj, int baudrate) { LPC_SYSCON->UARTCLKDIV = 0x1; uint32_t PCLK = SystemCoreClock; // First we check to see if the basic divide with no DivAddVal/MulVal // ratio gives us an integer result. If it does, we set DivAddVal = 0, // MulVal = 1. Otherwise, we search the valid ratio value range to find // the closest match. This could be more elegant, using search methods // and/or lookup tables, but the brute force method is not that much // slower, and is more maintainable. uint16_t DL = PCLK / (16 * baudrate); uint8_t DivAddVal = 0; uint8_t MulVal = 1; int hit = 0; uint16_t dlv; uint8_t mv, dav; if ((PCLK % (16 * baudrate)) != 0) { // Checking for zero remainder int err_best = baudrate, b; for (mv = 1; mv < 16 && !hit; mv++) { for (dav = 0; dav < mv; dav++) { // baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul)) // solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul)) // mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding // for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision // note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2; else // 2 bits headroom, use more precision dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2; // datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood if (dlv == 0) dlv = 1; // datasheet says if dav > 0 then DL must be >= 2 if ((dav > 0) && (dlv < 2)) dlv = 2; // integer rearrangement of the baudrate equation (with rounding) b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2; // check to see how we went b = abs(b - baudrate); if (b < err_best) { err_best = b; DL = dlv; MulVal = mv; DivAddVal = dav; if (b == baudrate) { hit = 1; break; } } } } } // set LCR[DLAB] to enable writing to divider registers obj->uart->LCR |= (1 << 7); // set divider values obj->uart->DLM = (DL >> 8) & 0xFF; obj->uart->DLL = (DL >> 0) & 0xFF; obj->uart->FDR = (uint32_t) DivAddVal << 0 | (uint32_t) MulVal << 4; // clear LCR[DLAB] obj->uart->LCR &= ~(1 << 7); } void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) { MBED_ASSERT((stop_bits == 1) || (stop_bits == 2)); // 0: 1 stop bits, 1: 2 stop bits MBED_ASSERT((data_bits > 4) && (data_bits < 9)); // 0: 5 data bits ... 3: 8 data bits MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven) || (parity == ParityForced1) || (parity == ParityForced0)); stop_bits -= 1; data_bits -= 5; int parity_enable = 0, parity_select = 0; switch (parity) { case ParityNone: parity_enable = 0; parity_select = 0; break; case ParityOdd : parity_enable = 1; parity_select = 0; break; case ParityEven: parity_enable = 1; parity_select = 1; break; case ParityForced1: parity_enable = 1; parity_select = 2; break; case ParityForced0: parity_enable = 1; parity_select = 3; break; default: break; } obj->uart->LCR = data_bits << 0 | stop_bits << 2 | parity_enable << 3 | parity_select << 4; } /****************************************************************************** * INTERRUPTS HANDLING ******************************************************************************/ static inline void uart_irq(uint32_t iir, uint32_t index) { // [Chapter 14] LPC17xx UART0/2/3: UARTn Interrupt Handling SerialIrq irq_type; switch (iir) { case 1: irq_type = TxIrq; break; case 2: irq_type = RxIrq; break; default: return; } if (serial_irq_ids[index] != 0) irq_handler(serial_irq_ids[index], irq_type); } void uart0_irq() {uart_irq((LPC_USART->IIR >> 1) & 0x7, 0);} void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) { irq_handler = handler; serial_irq_ids[obj->index] = id; } void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) { IRQn_Type irq_n = (IRQn_Type)0; uint32_t vector = 0; switch ((int)obj->uart) { case UART_0: irq_n=UART_IRQn ; vector = (uint32_t)&uart0_irq; break; } if (enable) { obj->uart->IER |= 1 << irq; NVIC_SetVector(irq_n, vector); NVIC_EnableIRQ(irq_n); } else { // disable int all_disabled = 0; SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq); obj->uart->IER &= ~(1 << irq); all_disabled = (obj->uart->IER & (1 << other_irq)) == 0; if (all_disabled) NVIC_DisableIRQ(irq_n); } } /****************************************************************************** * READ/WRITE ******************************************************************************/ int serial_getc(serial_t *obj) { while (!serial_readable(obj)); return obj->uart->RBR; } void serial_putc(serial_t *obj, int c) { while (!serial_writable(obj)); obj->uart->THR = c; } int serial_readable(serial_t *obj) { return obj->uart->LSR & 0x01; } int serial_writable(serial_t *obj) { return obj->uart->LSR & 0x20; } void serial_clear(serial_t *obj) { obj->uart->FCR = 1 << 1 // rx FIFO reset | 1 << 2 // tx FIFO reset | 0 << 6; // interrupt depth } void serial_pinout_tx(PinName tx) { pinmap_pinout(tx, PinMap_UART_TX); } void serial_break_set(serial_t *obj) { obj->uart->LCR |= (1 << 6); } void serial_break_clear(serial_t *obj) { obj->uart->LCR &= ~(1 << 6); }