mbed library sources
Dependents: frdm_kl05z_gpio_test
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Diff: targets/hal/TARGET_NXP/TARGET_LPC81X/serial_api.c
- Revision:
- 13:0645d8841f51
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_NXP/TARGET_LPC81X/serial_api.c Mon Aug 05 14:12:34 2013 +0300 @@ -0,0 +1,280 @@ +/* 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 "serial_api.h" +#include "cmsis.h" +#include "pinmap.h" +#include "error.h" + +/****************************************************************************** + * INITIALIZATION + ******************************************************************************/ +#define UART_NUM 3 + +static const SWM_Map SWM_UART_TX[] = { + {0, 0}, + {1, 8}, + {2, 16}, +}; + +static const SWM_Map SWM_UART_RX[] = { + {0, 8}, + {1, 16}, + {2, 24}, +}; + +// bit flags for used UARTs +static unsigned char uart_used = 0; +static int get_available_uart(void) { + int i; + for (i=0; i<3; i++) { + if ((uart_used & (1 << i)) == 0) + return i; + } + return -1; +} + +#define UART_EN (0x01<<0) + +#define CTS_DELTA (0x01<<5) +#define RXBRK (0x01<<10) +#define DELTA_RXBRK (0x01<<11) + +#define RXRDY (0x01<<0) +#define TXRDY (0x01<<2) + +#define TXBRKEN (0x01<<1) + +static uint32_t UARTSysClk; + +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; + + int uart_n = get_available_uart(); + if (uart_n == -1) { + error("No available UART"); + } + obj->index = uart_n; + obj->uart = (LPC_USART_TypeDef *)(LPC_USART0_BASE + (0x4000 * uart_n)); + uart_used |= (1 << uart_n); + + const SWM_Map *swm; + uint32_t regVal; + + swm = &SWM_UART_TX[uart_n]; + regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); + LPC_SWM->PINASSIGN[swm->n] = regVal | (tx << swm->offset); + + swm = &SWM_UART_RX[uart_n]; + regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); + LPC_SWM->PINASSIGN[swm->n] = regVal | (rx << swm->offset); + + /* uart clock divided by 1 */ + LPC_SYSCON->UARTCLKDIV = 1; + + /* disable uart interrupts */ + NVIC_DisableIRQ((IRQn_Type)(UART0_IRQn + uart_n)); + + /* Enable UART clock */ + LPC_SYSCON->SYSAHBCLKCTRL |= (1 << (14 + uart_n)); + + /* Peripheral reset control to UART, a "1" bring it out of reset. */ + LPC_SYSCON->PRESETCTRL &= ~(0x1 << (3 + uart_n)); + LPC_SYSCON->PRESETCTRL |= (0x1 << (3 + uart_n)); + + UARTSysClk = SystemCoreClock / LPC_SYSCON->UARTCLKDIV; + + // set default baud rate and format + serial_baud (obj, 9600); + serial_format(obj, 8, ParityNone, 1); + + /* Clear all status bits. */ + obj->uart->STAT = CTS_DELTA | DELTA_RXBRK; + + /* enable uart interrupts */ + NVIC_EnableIRQ((IRQn_Type)(UART0_IRQn + uart_n)); + + /* Enable UART interrupt */ + // obj->uart->INTENSET = RXRDY | TXRDY | DELTA_RXBRK; + + /* Enable UART */ + obj->uart->CFG |= UART_EN; + + is_stdio_uart = ((tx == USBTX) && (rx == USBRX)); + + if (is_stdio_uart) { + stdio_uart_inited = 1; + memcpy(&stdio_uart, obj, sizeof(serial_t)); + } +} + +void serial_free(serial_t *obj) { + uart_used &= ~(1 << obj->index); + 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) { + /* Integer divider: + BRG = UARTSysClk/(Baudrate * 16) - 1 + + Frational divider: + FRG = ((UARTSysClk / (Baudrate * 16 * (BRG + 1))) - 1) + + where + FRG = (LPC_SYSCON->UARTFRDADD + 1) / (LPC_SYSCON->UARTFRDSUB + 1) + + (1) The easiest way is set SUB value to 256, -1 encoded, thus SUB + register is 0xFF. + (2) In ADD register value, depending on the value of UartSysClk, + baudrate, BRG register value, and SUB register value, be careful + about the order of multiplier and divider and make sure any + multiplier doesn't exceed 32-bit boundary and any divider doesn't get + down below one(integer 0). + (3) ADD should be always less than SUB. + */ + obj->uart->BRG = UARTSysClk / 16 / baudrate - 1; + + LPC_SYSCON->UARTFRGDIV = 0xFF; + LPC_SYSCON->UARTFRGMULT = ( ((UARTSysClk / 16) * (LPC_SYSCON->UARTFRGDIV + 1)) / + (baudrate * (obj->uart->BRG + 1)) + ) - (LPC_SYSCON->UARTFRGDIV + 1); + +} + +void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) { + // 0: 1 stop bits, 1: 2 stop bits + if (stop_bits != 1 && stop_bits != 2) { + error("Invalid stop bits specified"); + } + stop_bits -= 1; + + // 0: 7 data bits ... 2: 9 data bits + if (data_bits < 7 || data_bits > 9) { + error("Invalid number of bits (%d) in serial format, should be 7..9", data_bits); + } + data_bits -= 7; + + int paritysel; + switch (parity) { + case ParityNone: paritysel = 0; break; + case ParityEven: paritysel = 2; break; + case ParityOdd : paritysel = 3; break; + default: + error("Invalid serial parity setting"); + return; + } + + obj->uart->CFG = (data_bits << 2) + | (paritysel << 4) + | (stop_bits << 6); +} + +/****************************************************************************** + * 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_USART0->STAT & (1 << 2)) ? 2 : 1, 0);} +void uart1_irq() {uart_irq((LPC_USART1->STAT & (1 << 2)) ? 2 : 1, 1);} +void uart2_irq() {uart_irq((LPC_USART2->STAT & (1 << 2)) ? 2 : 1, 2);} + +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 LPC_USART0_BASE: irq_n=UART0_IRQn; vector = (uint32_t)&uart0_irq; break; + case LPC_USART1_BASE: irq_n=UART1_IRQn; vector = (uint32_t)&uart1_irq; break; + case LPC_USART2_BASE: irq_n=UART2_IRQn; vector = (uint32_t)&uart2_irq; break; + } + + if (enable) { + obj->uart->INTENSET = (1 << ((irq == RxIrq) ? 0 : 2)); + NVIC_SetVector(irq_n, vector); + NVIC_EnableIRQ(irq_n); + } else { // disable + int all_disabled = 0; + SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq); + obj->uart->INTENSET &= ~(1 << ((irq == RxIrq) ? 0 : 2)); + all_disabled = (obj->uart->INTENSET & (1 << ((other_irq == RxIrq) ? 0 : 2))) == 0; + if (all_disabled) + NVIC_DisableIRQ(irq_n); + } +} + +/****************************************************************************** + * READ/WRITE + ******************************************************************************/ +int serial_getc(serial_t *obj) { + while (!serial_readable(obj)); + return obj->uart->RXDATA; +} + +void serial_putc(serial_t *obj, int c) { + while (!serial_writable(obj)); + obj->uart->TXDATA = c; +} + +int serial_readable(serial_t *obj) { + return obj->uart->STAT & RXRDY; +} + +int serial_writable(serial_t *obj) { + return obj->uart->STAT & TXRDY; +} + +void serial_clear(serial_t *obj) { + // [TODO] +} + +void serial_pinout_tx(PinName tx) { + +} + +void serial_break_set(serial_t *obj) { + obj->uart->CTRL |= TXBRKEN; +} + +void serial_break_clear(serial_t *obj) { + obj->uart->CTRL &= ~TXBRKEN; +} +