kolibrios/contrib/toolchain/avra/examples/throttle_momentum_lowpass.asm

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;throttle_momentum_lowpass.asm
.NOLIST
; ***************************************************************************************
; * PWM MODEL RAILROAD THROTTLE *
; * *
; * WRITTEN BY: PHILIP DEVRIES *
; * *
; * Copyright (C) 2003 Philip DeVries *
; * *
; * This program is free software; you can redistribute it and/or modify *
; * it under the terms of the GNU General Public License as published by *
; * the Free Software Foundation; either version 2 of the License, or *
; * (at your option) any later version. *
; * *
; * This program is distributed in the hope that it will be useful, *
; * but WITHOUT ANY WARRANTY; without even the implied warranty of *
; * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
; * GNU General Public License for more details. *
; * *
; * You should have received a copy of the GNU General Public License *
; * along with this program; if not, write to the Free Software *
; * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA *
; * *
; ***************************************************************************************
.LIST
.ifdef MOMENTUM_LOWPASS_ENABLED
;*****************************************************************
;* A transversal low pass filter *
;* *
;* This is copied from throttle_backemf.asm. *
;* See the documentation there. *
;*****************************************************************
HILOCAL1 _momentum_lo ; assign local variables
HILOCAL2 _momentum_hi
mov _momentum_lo,momentum_set
clr _momentum_hi
;****
;* 1. Add in cumulative previous throttle
;****
add _momentum_lo,momentum_lo_prev ; Add in scaled previous samples
adc _momentum_hi,momentum_hi_prev ;
;****
;* 2.
;****
mov momentum_lo_prev,_momentum_lo ; Store new value
mov momentum_hi_prev,_momentum_hi ; Store new value
;****
;* 3.
;****
B_TEMPLOCAL _lowpass_lo_byte
ldi _lowpass_lo_byte, momentum_lowpass_gain
rcall DIVIDE_16_SIMPLE
;****
;* 4.
;****
sub momentum_lo_prev,_momentum_lo
sbc momentum_hi_prev,_momentum_hi
mov momentum_set,_momentum_lo
.endif ;MOMENTUM_LOWPASS_ENABLED