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mbed-os/targets/TARGET_NXP/TARGET_LPC11U6X/serial_api.c

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/* 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"
#if DEVICE_SERIAL
/******************************************************************************
* INITIALIZATION
******************************************************************************/
#define UART_NUM 5
// CFG
#define UART_EN (0x01<<0)
// CTL
#define TXBRKEN (0x01<<1)
// STAT
#define RXRDY (0x01<<0)
#define TXRDY (0x01<<2)
#define DELTACTS (0x01<<5)
#define RXBRK (0x01<<10)
#define DELTARXBRK (0x01<<11)
static const PinMap PinMap_UART_TX[] = {
{P0_19, UART_0, 1},
{P1_18, UART_0, 2},
{P1_27, UART_0, 2},
{P1_8 , UART_1, 2},
{P0_14, UART_1, 4},
{P1_0 , UART_2, 3},
{P1_23, UART_2, 3},
{P2_4 , UART_3, 1},
{P2_12, UART_4, 1},
{ NC , NC , 0}
};
static const PinMap PinMap_UART_RX[] = {
{P0_18, UART_0, 1},
{P1_17, UART_0, 2},
{P1_26, UART_0, 2},
{P1_2 , UART_1, 3},
{P0_13, UART_1, 4},
{P0_20, UART_2, 2},
{P1_6 , UART_2, 2},
{P2_3 , UART_3, 1},
{P2_11, UART_4, 1},
{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);
switch (uart) {
case UART_0:
obj->index = 0;
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 12);
break;
case UART_1:
obj->index = 1;
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 20);
LPC_SYSCON->PRESETCTRL |= (1 << 5);
break;
case UART_2:
obj->index = 2;
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 21);
LPC_SYSCON->PRESETCTRL |= (1 << 6);
break;
case UART_3:
obj->index = 3;
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 22);
LPC_SYSCON->PRESETCTRL |= (1 << 7);
break;
case UART_4:
obj->index = 4;
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 22);
LPC_SYSCON->PRESETCTRL |= (1 << 8);
break;
}
if (obj->index == 0)
obj->uart = (LPC_USART0_Type *)uart;
else
obj->mini_uart = (LPC_USART4_Type *)uart;
if (obj->index == 0) {
// enable fifos and default rx trigger level
obj->uart->FCR = 1 << 0 // FIFO Enable - 0 = Disables, 1 = Enabled
| 0 << 1 // Rx Fifo Clear
| 0 << 2 // Tx Fifo Clear
| 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
}
else {
// Clear all status bits
obj->mini_uart->STAT = (DELTACTS | DELTARXBRK);
// Enable UART
obj->mini_uart->CFG |= UART_EN;
}
// 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);
}
is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
if (is_stdio_uart && (obj->index == 0)) {
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->USART0CLKDIV = 1;
LPC_SYSCON->FRGCLKDIV = 1;
if (obj->index == 0) {
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);
}
else {
uint32_t UARTSysClk = SystemCoreClock / LPC_SYSCON->FRGCLKDIV;
obj->mini_uart->BRG = UARTSysClk / 16 / baudrate - 1;
LPC_SYSCON->UARTFRGDIV = 0xFF;
LPC_SYSCON->UARTFRGMULT = ( ((UARTSysClk / 16) * (LPC_SYSCON->UARTFRGDIV + 1)) /
(baudrate * (obj->mini_uart->BRG + 1))
) - (LPC_SYSCON->UARTFRGDIV + 1);
}
}
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
stop_bits -= 1;
if (obj->index == 0) {
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));
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;
}
else {
// 0: 7 data bits ... 2: 9 data bits
MBED_ASSERT((data_bits > 6) && (data_bits < 10));
MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven));
data_bits -= 7;
int paritysel;
switch (parity) {
case ParityNone: paritysel = 0; break;
case ParityEven: paritysel = 2; break;
case ParityOdd : paritysel = 3; break;
default:
return;
}
obj->mini_uart->CFG = (data_bits << 2)
| (paritysel << 4)
| (stop_bits << 6)
| UART_EN;
}
}
/******************************************************************************
* INTERRUPTS HANDLING
******************************************************************************/
static inline void uart_irq(uint32_t iir, uint32_t index) {
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->IIR >> 1) & 0x7, 0);
}
void uart1_irq()
{
if(LPC_USART1->STAT & (1 << 2)){
uart_irq(1, 1);
}
if(LPC_USART1->STAT & (1 << 0)){
uart_irq(2, 1);
}
}
void uart2_irq()
{
if(LPC_USART2->STAT & (1 << 2)){
uart_irq(1, 2);
}
if(LPC_USART2->STAT & (1 << 0)){
uart_irq(2, 2);
}
}
void uart3_irq()
{
if(LPC_USART3->STAT & (1 << 2)){
uart_irq(1, 3);
}
if(LPC_USART3->STAT & (1 << 0)){
uart_irq(2, 3);
}
}
void uart4_irq()
{
if(LPC_USART4->STAT & (1 << 2)){
uart_irq(1, 4);
}
if(LPC_USART4->STAT & (1 << 0)){
uart_irq(2, 4);
}
}
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;
if(obj->index == 0){
irq_n = USART0_IRQn; vector = (uint32_t)&uart0_irq;
}
else{
switch ((int)obj->mini_uart) {
case UART_0: irq_n = USART0_IRQn; vector = (uint32_t)&uart0_irq; break;
case UART_1: irq_n = USART1_4_IRQn; vector = (uint32_t)&uart1_irq; break;
case UART_2: irq_n = USART2_3_IRQn; vector = (uint32_t)&uart2_irq; break;
case UART_3: irq_n = USART2_3_IRQn; vector = (uint32_t)&uart3_irq; break;
case UART_4: irq_n = USART1_4_IRQn; vector = (uint32_t)&uart4_irq; break;
}
}
if (enable) {
if (obj->index == 0) {
obj->uart->IER |= (1 << irq);
}
else {
obj->mini_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) ? (RxIrq) : (TxIrq);
if (obj->index == 0) {
obj->uart->IER &= ~(1 << irq);
all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
}
else {
obj->mini_uart->INTENCLR = (1 << ((irq == RxIrq) ? 0 : 2));
all_disabled = (obj->mini_uart->INTENSET) == 0;
}
if (all_disabled)
NVIC_DisableIRQ(irq_n);
}
}
/******************************************************************************
* READ/WRITE
******************************************************************************/
int serial_getc(serial_t *obj) {
while (!serial_readable(obj));
if (obj->index == 0) {
return obj->uart->RBR;
}
else {
return obj->mini_uart->RXDAT;
}
}
void serial_putc(serial_t *obj, int c) {
while (!serial_writable(obj));
if (obj->index == 0) {
obj->uart->THR = c;
}
else {
obj->mini_uart->TXDAT = c;
}
}
int serial_readable(serial_t *obj) {
if (obj->index == 0) {
return obj->uart->LSR & 0x01;
}
else {
return obj->mini_uart->STAT & RXRDY;
}
}
int serial_writable(serial_t *obj) {
if (obj->index == 0) {
return obj->uart->LSR & 0x20;
}
else {
return obj->mini_uart->STAT & TXRDY;
}
}
void serial_clear(serial_t *obj) {
if (obj->index == 0) {
obj->uart->FCR = 1 << 1 // rx FIFO reset
| 1 << 2 // tx FIFO reset
| 0 << 6; // interrupt depth
}
else {
obj->mini_uart->STAT = 0;
}
}
void serial_pinout_tx(PinName tx) {
pinmap_pinout(tx, PinMap_UART_TX);
}
void serial_break_set(serial_t *obj) {
if (obj->index == 0) {
obj->uart->LCR |= (1 << 6);
}
else {
obj->mini_uart->CTL |= TXBRKEN;
}
}
void serial_break_clear(serial_t *obj) {
if (obj->index == 0) {
obj->uart->LCR &= ~(1 << 6);
}
else {
obj->mini_uart->CTL &= ~TXBRKEN;
}
}
const PinMap *serial_tx_pinmap()
{
return PinMap_UART_TX;
}
const PinMap *serial_rx_pinmap()
{
return PinMap_UART_RX;
}
const PinMap *serial_cts_pinmap()
{
#if !DEVICE_SERIAL_FC
static const PinMap PinMap_UART_CTS[] = {
{NC, NC, 0}
};
#endif
return PinMap_UART_CTS;
}
const PinMap *serial_rts_pinmap()
{
#if !DEVICE_SERIAL_FC
static const PinMap PinMap_UART_RTS[] = {
{NC, NC, 0}
};
#endif
return PinMap_UART_RTS;
}
#endif
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