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Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c')
| -rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c b/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c new file mode 100644 index 0000000000..5020afc54b --- /dev/null +++ b/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC13XX/serial_api.c @@ -0,0 +1,300 @@ +/* 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 "mbed_assert.h" +#include <math.h> +#include <string.h> +#include <stdlib.h> + +#include "serial_api.h" +#include "cmsis.h" +#include "pinmap.h" + +/****************************************************************************** + * INITIALIZATION + ******************************************************************************/ +#define UART_NUM 1 + +static const PinMap PinMap_UART_TX[] = { + {P0_19, UART_0, 1}, + {P1_13, UART_0, 3}, + {P1_27, UART_0, 2}, + { NC , NC , 0} +}; + +static const PinMap PinMap_UART_RX[] = { + {P0_18, UART_0, 1}, + {P1_14, UART_0, 3}, + {P1_26, UART_0, 2}, + {NC , NC , 0} +}; + +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 + //pin_function(USBTX, 0); + //pin_function(USBRX, 0); + + // 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 + if (tx != NC) { + pin_mode(tx, PullUp); + } + if (rx != NC) { + 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, parity_select; + 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=USART_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); +} + |