encoder.inc

来自「dsPIC数字信号控制器对于交流感应电机矢量控制的应用笔记的源代码及详细说明资料」· INC 代码 · 共 36 行

;;------------------  ASM30 API for Encoder routines ---------------------
; EncoderParm stucture:

          .equ Encod_qMechAng,0      ; Mechanical rotational angle in 1.15 format      
          .equ Encod_qKang,2         ; Constant: Count to Angle scaling                
          .equ Encod_iCntsPerRev,4   ; Constant: Encoder counts per revolution of motor
                                                                                       
          .equ Encod_qVelMech,6      ; Mechanical rotational velocity in 1.15          
          .equ Encod_qKvel,8         ; Constant: Count to velocity scaling             
          .equ Encod_iIrpPerCalc,10      ; Constant: Number of timer ticks per speed calc  

     ;; private

          .equ Encod_iVelCntDwn,12   ; Countdown to next speed calc
          .equ Encod_iPrevCnt,14     ; Last encoder value
          .equ Encod_iAccumCnt,16    ; Accumulating cnts
          .equ Encod_iDeltaCnt,18;   ; Accumulated cnts waiting for Velocity calc

          .extern _EncoderParm

; See discussion in CalcAng.s for proper value of Nang.
          .equ Nang,8         ; Nang must satisfy 64 <= 2^Nang < CntsPerRev

; Angular velocity scaling:  iVelMech = qKvel * DeltaCnt / 2^Nvel
;
; where qKvel = (2^15)*(2^Nvel)/MaxDeltaCnt.
;
; The Nvel scaling factor is picked to maximize precision without causing 
; qKvel to overflow 1.15 format. To do this Nvel must be small enough so that 
; 2^Nvel/MaxDeltaCnt < 1 but large enough to provide required precision.

; Assume MaxDeltaCnt > 256 => Nvel = 8
          .equ Nvel,8           ; Nvel must be in range -8 <= 15-Nvel <= +7
                                ; Must be changed in encoder.h also