125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
|
|
/*
|
|
* uart.c
|
|
*
|
|
* Copyright (c) 2005 Robert Krten. All Rights Reserved.
|
|
*
|
|
* 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
|
|
*
|
|
* This module contains a simple 8-bit UART, which performs a callback
|
|
* with the decoded byte value.
|
|
*
|
|
* 2005 06 11 R. Krten created
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
|
|
#include "uart.h"
|
|
|
|
/*
|
|
* dsp_uart_attr_init
|
|
*
|
|
* Initializes the attributes structure; this must be done before the
|
|
* attributes structure is used.
|
|
*/
|
|
|
|
void dsp_uart_attr_init (dsp_uart_attr_t *attr)
|
|
{
|
|
memset (attr, 0, sizeof (*attr));
|
|
}
|
|
|
|
/*
|
|
* dsp_uart_attr_get_bytehandler
|
|
* dsp_uart_attr_set_bytehandler
|
|
*
|
|
* These functions get and set their respective elements from the
|
|
* attributes structure. If an error code is returned, it is just
|
|
* zero == ok, -1 == fail.
|
|
*/
|
|
|
|
bytehandler_func_t dsp_uart_attr_get_bytehandler(dsp_uart_attr_t *attr, void **bytehandler_arg)
|
|
{
|
|
*bytehandler_arg = attr->bytehandler_arg;
|
|
return attr->bytehandler;
|
|
}
|
|
|
|
void dsp_uart_attr_set_bytehandler(dsp_uart_attr_t *attr, bytehandler_func_t bytehandler, void *bytehandler_arg)
|
|
{
|
|
attr->bytehandler = bytehandler;
|
|
attr->bytehandler_arg = bytehandler_arg;
|
|
}
|
|
|
|
dsp_uart_handle_t *dsp_uart_create(dsp_uart_attr_t *attr)
|
|
{
|
|
dsp_uart_handle_t *handle;
|
|
|
|
handle = malloc(sizeof (*handle));
|
|
if (handle) {
|
|
memset(handle, 0, sizeof (*handle));
|
|
|
|
/* fill the attributes member */
|
|
memcpy(&handle->attr, attr, sizeof (*attr));
|
|
}
|
|
return handle;
|
|
}
|
|
|
|
void dsp_uart_destroy(dsp_uart_handle_t **handle)
|
|
{
|
|
if (*handle) {
|
|
free(*handle);
|
|
*handle = NULL;
|
|
}
|
|
}
|
|
|
|
|
|
void dsp_uart_bit_handler(void *x, int bit)
|
|
{
|
|
dsp_uart_handle_t *handle = (dsp_uart_handle_t *) x;
|
|
|
|
if (!handle->have_start) {
|
|
if (bit) {
|
|
return; /* waiting for start bit (0) */
|
|
}
|
|
handle->have_start = 1;
|
|
handle->data = 0;
|
|
handle->nbits = 0;
|
|
return;
|
|
}
|
|
|
|
handle->data >>= 1;
|
|
handle->data |= 0x80 * !!bit;
|
|
handle->nbits++;
|
|
|
|
if (handle->nbits == 8) {
|
|
handle->attr.bytehandler(handle->attr.bytehandler_arg, handle->data);
|
|
handle->nbits = 0;
|
|
handle->data = 0;
|
|
handle->have_start = 0;
|
|
}
|
|
/* might consider handling errors in the future... */
|
|
}
|
|
|