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

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;throttle_set_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 THROTTLE_LOWPASS_ENABLED
;*****************************************************************
;* A transversal low pass filter *
;* *
;* This is copied from throttle_backemf.asm. *
;* See the documentation there. *
;*****************************************************************
HILOCAL1 throttle_lo ; assign local variables
HILOCAL2 throttle_hi
mov throttle_lo,throttle_set
clr throttle_hi
;****
;* 1. Add in cumulative previous throttle
;****
add throttle_lo,throttle_lo_prev ; Add in scaled previous samples
adc throttle_hi,throttle_hi_prev ;
;****
;* 2.
;****
mov throttle_lo_prev,throttle_lo ; Store new value
mov throttle_hi_prev,throttle_hi ; Store new value
;****
;* 3.
;****
B_TEMPLOCAL _lowpass_lo_byte
ldi _lowpass_lo_byte, throttle_lowpass_gain
rcall DIVIDE_16_SIMPLE
;****
;* 4.
;****
sub throttle_lo_prev,throttle_lo
sbc throttle_hi_prev,throttle_hi
mov throttle_set,throttle_lo
.endif ;THROTTLE_LOWPASS_FILTER