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authorpatacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>2007-02-18 23:46:29 +0000
committerpatacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>2007-02-18 23:46:29 +0000
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Preparing to test on the C5471
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@7 42af7a65-404d-4744-a932-0658087f49c3
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+/**************************************************************************
+ * up_lowputc.S
+ *
+ * Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ * Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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 Gregory Nutt 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 <nuttx/config.h>
+#include "up_internal.h"
+#include "c5471.h"
+
+/**************************************************************************
+ * Private Definitions
+ **************************************************************************/
+
+/**************************************************************************
+ * 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_putc
+ .type up_lowputc, function
+up_lowputc:
+ /* On entry, r0 holds the character to be printed */
+
+#ifdef CONFIG_SERIAL_IRDA_CONSOLE
+ ldr r2, =UART_IRDA_BASE /* r2=IRDA UART base */
+#else
+ ldr r2, =UART_MODEM_BASE /* r2=Modem UART base */
+#endif
+
+ /* Poll bit 0 of the UART_SSR register. When the bit
+ * is clear, the TX FIFO is no longer full
+ */
+
+1: ldr r1, [r2, #UART_SSR_OFFS]
+ tst r1, #UART_SSR_TXFULL
+ bne 1b
+
+ /* Send the character by writing it into the UART_THR
+ * register.
+ */
+
+ str r0, [r2, #UART_THR_OFFS]
+
+ /* Wait for the tranmsit holding regiser (THR) to be
+ * emptied. This is detemined when bit 6 of the LSR
+ * is set.
+ */
+
+2: ldr r1, [r2, #UART_LSR_OFFS]
+ tst r1, #0x00000020
+ beq 2b
+
+ /* If the character that we just sent was a linefeed,
+ * then send a carriage return as well.
+ */
+
+ teq r0, #'\n'
+ moveq r0, #'\r'
+ beq 1b
+
+ /* And return */
+
+ mov pc, lr
+