141 lines
5.8 KiB
NASM
141 lines
5.8 KiB
NASM
;throttle_pulse.asm
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.NOLIST
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; ***************************************************************************************
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; * PWM MODEL RAILROAD THROTTLE *
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; * *
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; * WRITTEN BY: PHILIP DEVRIES *
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; * *
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; * Copyright (C) 2003 Philip DeVries *
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; * *
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; * This program is free software; you can redistribute it and/or modify *
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; * it under the terms of the GNU General Public License as published by *
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; * the Free Software Foundation; either version 2 of the License, or *
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; * (at your option) any later version. *
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; * *
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; * This program is distributed in the hope that it will be useful, *
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; * but WITHOUT ANY WARRANTY; without even the implied warranty of *
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; * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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; * GNU General Public License for more details. *
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; * *
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; * You should have received a copy of the GNU General Public License *
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; * along with this program; if not, write to the Free Software *
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; * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
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; * *
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; ***************************************************************************************
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.LIST
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.ifdef PULSE_ENABLED
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;********************************************************************************
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;* PULSE_GENERATE *
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;* Top level routine *
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;* *
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;* Inputs: throttle_set *
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;* Returns: none *
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;* Changed: B_Temp,ramp_target,ramp_target1 *
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;* Calls: SET_PWM_DUTY *
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;* COUNT_PWM_CYCLES *
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;* Goto: none *
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;********************************************************************************
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HILOCAL1 ramp_target
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HILOCAL2 ramp_target1
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;*****************************************************************
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;* If throttle_set is less than 128 (0x80)
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;* Ramp up from wherever the pwm is up to (255 - throttle)
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;* If throttle_set is greater than 127 0x7F)
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;* Ramp up to throttle_set
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;*****************************************************************
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mov ramp_target1,throttle_set
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sbrs ramp_target1,7
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.ifdef PULSE_AMPLITUDE_SCALE
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com ramp_target1 ; Ramp up to this value
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.else
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ldi ramp_target1,0x80
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.endif
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mov ramp_target,ramp_target1
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subi ramp_target,pulse_slope_up ; Ramp up value - pulse_slope
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WAIT_FOR_PWM_1: ; Wait for PWM to reset to 0
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in B_Temp,TIFR
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sbrs B_Temp,OCF1A
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rjmp WAIT_FOR_PWM_1
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ldi B_Temp,0b01000000
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out TIFR,B_Temp
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inc Cycle_count
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in B_Temp,OCR1A ; Find PWM value
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cp B_Temp,ramp_target ; Make sure won't go past max.
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brsh DONE_SLOPING_UP
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subi B_Temp, 0x100-pulse_slope_up ; OCR1A + pulse_slope_up
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rcall SET_PWM_DUTY
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rjmp WAIT_FOR_PWM_1
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DONE_SLOPING_UP:
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mov B_Temp,ramp_target1
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rcall SET_PWM_DUTY
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;*****************************************************************
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;* See if we need to slope down to the throttle setting
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;*****************************************************************
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in B_Temp,OCR1A ; Find PWM value
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cp B_Temp,throttle_set
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breq PULSE_GENERATE_RETURN ; Do nothing if already at final voltage
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;*****************************************************************
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;* Hang about at the top of the pulse for a while...
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;*****************************************************************
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.ifdef PULSE_WIDTH_SCALE
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mov ramp_target1,throttle_set
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.else
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clr ramp_target1
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.endif
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add ramp_target1,Cycle_count
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subi ramp_target1,0x100-pulse_width_min ; ramp_target1 + pulse_width_min
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mov B_Temp1,ramp_target1
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rcall COUNT_PWM_CYCLES
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;*****************************************************************
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;* Slope down
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;*****************************************************************
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mov ramp_target,throttle_set ; Ramp DOWN to this value
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subi ramp_target,0x100-pulse_slope_down ;ramp_target + pulse_slope_down
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WAIT_FOR_PWM_2: ; Wait for PWM to reset to 0
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in B_Temp,TIFR
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sbrs B_Temp,OCF1A
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rjmp WAIT_FOR_PWM_2
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ldi B_Temp,0b01000000
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out TIFR,B_Temp
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inc Cycle_count
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in B_Temp,OCR1A ; Find PWM value
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cp ramp_target,B_Temp ; Make sure won't go past min
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brsh PULSE_GENERATE_RETURN
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subi B_Temp,pulse_slope_down
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rcall SET_PWM_DUTY
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rjmp WAIT_FOR_PWM_2
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PULSE_GENERATE_RETURN:
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.endif ;PULSE_ENABLED
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