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libswd_bitgen.c
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libswd_bitgen.c
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/*
* Serial Wire Debug Open Library.
* Library Body File.
*
* Copyright (C) 2010-2013, Tomasz Boleslaw CEDRO (http://www.tomek.cedro.info)
* 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.
* 3. Neither the name of the Tomasz Boleslaw CEDRO 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 HOLDER 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.*
*
* Written by Tomasz Boleslaw CEDRO <[email protected]>, 2010-2013;
*
*/
/** \file libswd_bitgen.c */
#include <libswd.h>
/*******************************************************************************
* \defgroup libswd_bitgen SWD Bitstream / Packet Payload generation routines.
* @{
******************************************************************************/
/** Generate 8-bit SWD-REQUEST packet contents with provided parameters.
* Note that parity bit value is calculated automatically.
* Note that Request is also sent LSB-First so diagrams are wrapped!
* \param *libswdctx swd context pointer.
* \param *APnDP AccessPort (high) or DebugPort (low) access type pointer.
* \param *RnW Read (high) or Write (low) operation type pointer.
* \param *addr target register address value pointer.
* \param *request pointer where to store resulting packet.
* \return number of generated packets (1), or LIBSWD_ERROR_CODE on failure.
*/
int libswd_bitgen8_request(libswd_ctx_t *libswdctx, char *APnDP, char *RnW, char *addr, char *request){
/* Verify function parameters.*/
if (libswdctx==NULL) return LIBSWD_ERROR_NULLCONTEXT;
if (*APnDP!=0 && *APnDP!=1) return LIBSWD_ERROR_APnDP;
if (*RnW!=0 && *RnW!=1) return LIBSWD_ERROR_RnW;
if (*addr<LIBSWD_ADDR_MINVAL && *addr>LIBSWD_ADDR_MAXVAL) return LIBSWD_ERROR_ADDR;
/* Build request header content. */
unsigned char reqhdr=0;
char parity, req;
int res;
reqhdr|=(((*addr&(1<<2))?1:0)<<LIBSWD_REQUEST_A2_BITNUM);
reqhdr|=(((*addr&(1<<3))?1:0)<<LIBSWD_REQUEST_A3_BITNUM);
reqhdr|=((*APnDP?1:0)<<LIBSWD_REQUEST_APnDP_BITNUM);
reqhdr|=(((*RnW?1:0)<<LIBSWD_REQUEST_RnW_BITNUM));
req=reqhdr;
res=libswd_bin8_parity_even(&req, &parity);
if (res<0) return res;
if (parity<0 || parity>1) return LIBSWD_ERROR_PARITY;
reqhdr|=(res<<LIBSWD_REQUEST_PARITY_BITNUM);
reqhdr|=(LIBSWD_REQUEST_START_VAL<<LIBSWD_REQUEST_START_BITNUM);
reqhdr|=(LIBSWD_REQUEST_STOP_VAL<<LIBSWD_REQUEST_STOP_BITNUM);
reqhdr|=(LIBSWD_REQUEST_PARK_VAL<<LIBSWD_REQUEST_PARK_BITNUM);
*request=reqhdr;
return 1;
}
/** @} */