################################################################################
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################################################################################
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## This sourcecode is released under BSD license.
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## This sourcecode is released under BSD license.
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## Please see http://www.opensource.org/licenses/bsd-license.php for details!
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## Please see http://www.opensource.org/licenses/bsd-license.php for details!
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################################################################################
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################################################################################
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##
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##
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## Copyright (c) 2010, Stefan Fischer <Ste.Fis@OpenCores.org>
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## Copyright (c) 2010, Stefan Fischer <Ste.Fis@OpenCores.org>
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## All rights reserved.
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## All rights reserved.
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##
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##
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## Redistribution and use in source and binary forms, with or without
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## Redistribution and use in source and binary forms, with or without
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## modification, are permitted provided that the following conditions are met:
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## modification, are permitted provided that the following conditions are met:
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##
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##
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## * Redistributions of source code must retain the above copyright notice,
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## * Redistributions of source code must retain the above copyright notice,
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## this list of conditions and the following disclaimer.
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## this list of conditions and the following disclaimer.
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## * Redistributions in binary form must reproduce the above copyright notice,
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## * Redistributions in binary form must reproduce the above copyright notice,
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## this list of conditions and the following disclaimer in the documentation
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## this list of conditions and the following disclaimer in the documentation
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## and/or other materials provided with the distribution.
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## and/or other materials provided with the distribution.
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## * Neither the name of the author nor the names of his contributors may be
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## * Neither the name of the author nor the names of his contributors may be
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## used to endorse or promote products derived from this software without
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## used to endorse or promote products derived from this software without
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## specific prior written permission.
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## specific prior written permission.
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##
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##
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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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## ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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## ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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## LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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## CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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## SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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## INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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## INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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## CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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## CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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## ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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## ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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## POSSIBILITY OF SUCH DAMAGE.
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## POSSIBILITY OF SUCH DAMAGE.
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##
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##
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################################################################################
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################################################################################
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## filename: baud_rate_calculator.tcl
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## filename: baud_rate_calculator.tcl
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## description: tcl-script generating assembler constants for standard baud
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## description: tcl-script generating assembler constants for standard baud
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## rates
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## rates
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## todo4user: 1. modify output file path, SYSTEM_CLOCK and BAUD_RATES as needed
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## todo4user: 1. modify output file path, SYSTEM_CLOCK and BAUD_RATES as needed
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## 2. run script with TCL interpreter of your choice, i. e. from
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## 2. run script with TCL interpreter of your choice, i. e. from
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## ModelSim (R) GUI: Menu->Tools->TCL->Execute Macro...
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## ModelSim (R) GUI: Menu->Tools->TCL->Execute Macro...
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## 3. copy and paste file content from generated
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## 3. copy and paste file content from generated
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## baud_rate_constants.txt to assembler source code
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## baud_rate_constants.txt to assembler source code
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## version: 0.0.0
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## version: 0.0.0
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## changelog: - 0.0.0, initial release
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## changelog: - 0.0.0, initial release
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## - ...
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## - ...
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################################################################################
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################################################################################
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# output file path
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# output file path
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cd "e:/home_users/ste.fis/projects/wb4pb/trunk/asm"
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cd "e:/home_users/ste.fis/projects/wb4pb/trunk/asm"
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# reference clock, normally several MHz
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# reference clock, normally several MHz
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set SYSTEM_CLOCK 50.0E6
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set SYSTEM_CLOCK 50.0E6
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# some standard baud rates
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# some standard baud rates
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set BAUD_RATES {
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set BAUD_RATES {
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300
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300
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600
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600
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1200
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1200
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2400
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2400
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4800
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4800
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9600
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9600
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19200
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19200
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38400
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38400
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57600
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57600
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115200
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115200
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230400
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230400
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460800
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460800
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921600
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921600
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}
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}
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# open file handle
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# open file handle
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set f [open "baud_rate_constants.txt" w]
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set f [open "baud_rate_constants.txt" w]
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# baud rate configuration:
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# baud rate configuration:
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# baud_limit = round( system clock frequency / (16 * baud rate) ) - 1
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# baud_limit = round( system clock frequency / (16 * baud rate) ) - 1
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# i. e. 9600 baud at 50 MHz system clock =>
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# i. e. 9600 baud at 50 MHz system clock =>
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# baud_limit = round( 50.0E6 / (16 * 9600) ) - 1 = 325 = 0x0145
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# baud_limit = round( 50.0E6 / (16 * 9600) ) - 1 = 325 = 0x0145
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# WARNING, baud rate error should not exceed 1.0 % for reliable operation!
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# WARNING, baud rate error should not exceed 1.0 % for reliable operation!
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# calculating baud min. and max. values
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# calculating baud min. and max. values
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set baud_max [expr floor($SYSTEM_CLOCK / 16)]
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set baud_max [expr floor($SYSTEM_CLOCK / 16)]
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set baud_min [expr ceil($SYSTEM_CLOCK / (16 * 65536))]
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set baud_min [expr ceil($SYSTEM_CLOCK / (16 * 65536))]
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puts $f "; baud rate settings for $SYSTEM_CLOCK Hz system reference clock"
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puts $f "; baud rate settings for $SYSTEM_CLOCK Hz system reference clock"
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puts $f "; max. $baud_max baud"
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puts $f "; max. $baud_max baud"
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puts $f "; min. $baud_min baud (16 bit baud timer)"
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puts $f "; min. $baud_min baud (16 bit baud timer)"
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foreach baud_rate $BAUD_RATES {
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foreach baud_rate $BAUD_RATES {
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# checking, if current baud rate works with system hardware parameters
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# checking, if current baud rate works with system hardware parameters
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if {[expr $baud_min <= $baud_rate] && [expr $baud_rate <= $baud_max]} {
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if {[expr $baud_min <= $baud_rate] && [expr $baud_rate <= $baud_max]} {
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# calculating hardware baud timer limit
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# calculating hardware baud timer limit
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set baud_limit [expr round($SYSTEM_CLOCK / (16 * $baud_rate)) - 1]
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set baud_limit [expr round($SYSTEM_CLOCK / (16 * $baud_rate)) - 1]
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# calculating actual hardware baud rate
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# calculating actual hardware baud rate
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set actual_baud_rate [expr $SYSTEM_CLOCK / (16 * ($baud_limit + 1))]
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set actual_baud_rate [expr $SYSTEM_CLOCK / (16 * ($baud_limit + 1))]
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# calculating baud rate error, value is commented out automatically, if
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# calculating baud rate error, value is commented out automatically, if
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# frequency error is greater than the recommended 1 %
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# frequency error is greater than the recommended 1 %
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if {
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if {
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[set baud_error [expr abs(($baud_rate / $actual_baud_rate) - 1)]] > 0.01
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[set baud_error [expr abs(($baud_rate / $actual_baud_rate) - 1)]] > 0.01
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} {
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} {
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set comment ";"
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set comment ";"
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} else {
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} else {
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set comment ""
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set comment ""
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}
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}
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# generating a 16 bit, 4 character hexadecimal string of hardware baud timer
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# generating a 16 bit, 4 character hexadecimal string of hardware baud timer
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# limit
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# limit
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set baud_limit_hex [format %04X $baud_limit]
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set baud_limit_hex [format %04X $baud_limit]
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# creating strings with constant definitions in kcpsm3 assembler syntax,
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# creating strings with constant definitions in kcpsm3 assembler syntax,
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# splitting into high and low byte
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# splitting into high and low byte
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puts $f "${comment}CONSTANT UART_BAUD_LO_${baud_rate}_VALUE , [string range\
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puts $f "${comment}CONSTANT UART_BAUD_LO_${baud_rate}_VALUE , [string range\
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$baud_limit_hex 2 3] ; actual baud rate [format %.2f \
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$baud_limit_hex 2 3] ; actual baud rate [format %.2f\
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$actual_baud_rate]"
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$actual_baud_rate]"
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puts $f "${comment}CONSTANT UART_BAUD_HI_${baud_rate}_VALUE , [string range\
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puts $f "${comment}CONSTANT UART_BAUD_HI_${baud_rate}_VALUE , [string range\
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$baud_limit_hex 0 1] ; => baud rate error [format %.3f [expr 100 *\
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$baud_limit_hex 0 1] ; => baud rate error [format %.3f [expr 100 *\
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$baud_error]] %"
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$baud_error]] %"
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}
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}
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}
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}
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# closing file
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# closing file
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close $f
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close $f
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