/************************************************************************** * arch/arm/src/lpc214x/lpc214X_lowputc.S * * Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * **************************************************************************/ /************************************************************************** * Included Files **************************************************************************/ #include #include "chip.h" #include "up_arch.h" #include "up_internal.h" #include "lpc214x_pinsel.h" #include "lpc214x_uart.h" /************************************************************************** * Private Definitions **************************************************************************/ #if defined(CONFIG_UART0_SERIAL_CONSOLE) # define LPC214X_UART_BASE LPC214X_UART0_BASE # define LPC214X_UART_PINSEL LPC214X_UART0_PINSEL # define LPC214X_UART_PINMASK LPC214X_UART0_PINMASK # define LPC214X_UART_BAUD CONFIG_UART0_BAUD # define LPC214X_UART_BITS CONFIG_UART0_BITS # define LPC214X_UART_PARITY CONFIG_UART0_PARITY # define LPC214X_UART_2STOP CONFIG_UART0_2STOP #elif defined(CONFIG_UART1_SERIAL_CONSOLE) # define LPC214X_UART_BASE LPC214X_UART1_BASE # define LPC214X_UART_PINSEL LPC214X_UART1_PINSEL # define LPC214X_UART_PINMASK LPC214X_UART1_PINMASK # define LPC214X_UART_BAUD CONFIG_UART1_BAUD # define LPC214X_UART_BITS CONFIG_UART1_BITS # define LPC214X_UART_PARITY CONFIG_UART1_PARITY # define LPC214X_UART_2STOP CONFIG_UART1_2STOP #else # error "No CONFIG_UARTn_SERIAL_CONSOLE Setting" #endif #if LPC214X_UART_BITS == 5 # define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_5 #elif LPC214X_UART_BITS == 6 # define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_6 #elif LPC214X_UART_BITS == 7 # define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_7 #elif LPC214X_UART_BITS == 8 # define LPC214X_LCR_CHAR LPC214X_LCR_CHAR_8 #else # error "No CONFIG_UARTn_BITS Setting" #endif #if LPC214X_UART_PARITY == 0 # define LPC214X_LCR_PAR LPC214X_LCR_PAR_NONE #elif LPC214X_UART_PARITY == 1 # define LPC214X_LCR_PAR LPC214X_LCR_PAR_ODD #elif LPC214X_UART_PARITY == 2 # define LPC214X_LCR_PAR LPC214X_LCR_PAR_EVEN #elif LPC214X_UART_PARITY == 3 # define LPC214X_LCR_PAR LPC214X_LCR_PAR_MARK #elif LPC214X_UART_PARITY == 4 # define LPC214X_LCR_PAR LPC214X_LCR_PAR_SPACE #else # error "No CONFIG_UARTn_PARITY Setting" #endif #if LPC214X_UART_2STOP != 0 # define LPC214X_LCR_STOP LPC214X_LCR_STOP_2 #else # define LPC214X_LCR_STOP LPC214X_LCR_STOP_1 #endif #define LPC214X_LCR_VALUE (LPC214X_LCR_CHAR | LPC214X_LCR_PAR | LPC214X_LCR_STOP) #define LPC214X_FCR_VALUE (LPC214X_FCR_FIFO_TRIG8 | LPC214X_FCR_TX_FIFO_RESET |\ LPC214X_FCR_RX_FIFO_RESET | LPC214X_FCR_FIFO_ENABLE) /************************************************************************** * Private Types **************************************************************************/ /************************************************************************** * Private Function Prototypes **************************************************************************/ /************************************************************************** * Global Variables **************************************************************************/ /************************************************************************** * Private Variables **************************************************************************/ /************************************************************************** * Private Functions **************************************************************************/ /************************************************************************** * Public Functions **************************************************************************/ /************************************************************************** * Name: up_lowputc **************************************************************************/ /* This assembly language version has the advantage that it can does not * require a C stack and uses only r0-r1. Hence it can be used during * early boot phases. */ .text .global up_lowputc .type up_lowputc, function up_lowputc: /* On entry, r0 holds the character to be printed */ ldr r1, =LPC214X_UART_BASE strb r0, [r1, #LPC214X_UART_THR_OFFSET] /* Wait for the byte to be transferred */ 1: ldr r0, [r1, #LPC214X_UART_LSR_OFFSET] ands r0, #LPC214X_LSR_TEMT /* Transmitter empty */ beq 1b /* And return */ mov pc, lr .size up_lowputc, . - up_lowputc /* This performs basic initialization of the UART. This can be called very * early in initialization because it does not depend on having a stack. It * modifies r0-r2 and r14. */ .text .globl up_lowsetup .type up_lowsetup, function up_lowsetup: /* Configure PINSEL0 */ ldr r0, =LPC214X_PINSEL0 ldr r1, [r0] ldr r2, =~LPC214X_UART_PINMASK and r1, r2 ldr r2, =LPC214X_UART_PINSEL orr r1, r2 str r1, [r0] /* Configure parity, data bits, stop bits and set DLAB=1 */ ldr r0, =LPC214X_UART_BASE mov r1, #(LPC214X_LCR_VALUE | LPC214X_LCR_DLAB_ENABLE) strb r1, [r0, #LPC214X_UART_LCR_OFFSET] /* Set the BAUD divisor */ mov r1, #(UART_BAUD(LPC214X_UART_BAUD) >> 8) strb r1, [r0, #LPC214X_UART_DLM_OFFSET] mov r1, #(UART_BAUD(LPC214X_UART_BAUD) & 0xff) strb r1, [r0, #LPC214X_UART_DLL_OFFSET] /* Clear DLAB */ mov r1, #LPC214X_LCR_VALUE strb r1, [r0, #LPC214X_UART_LCR_OFFSET] /* Configure the FIFOs */ mov r1, #LPC214X_FCR_VALUE strb r1, [r0, #LPC214X_UART_FCR_OFFSET] /* And return */ mov pc, lr .size up_lowsetup, . - up_lowsetup .end