Rotary encoder emulation
It has been a while since I have posted here. I am currently working on a project where I am trying to emulate a rotary encoder. There is a small dc motor that bidirectionally drives the mechanism that contains the encoder. The motor control uses a duty cycle to control the speed and direction of the motor. What I am trying to do is eliminate the whole mechanism and replace it with a propeller that fools the controller into thinking the mechanism is still present. My original plan was to watch the signal to the motor and increment a counter whenever the signal was high in the forward direction and decrement the counter whenever the signal was high in the reverse direction. The watch the counter and output the signals for the encoder whenever the counter reached the proper positions. Do you all think this is the best way to do this? I have attached a screenshot of one full rotation of the encoder, you can see when the signal starts to repeat. The normal idle state for the encoder is all three channels high. I have also attached the code I have tested and works for one part of the function but when the motor runs in reverse, that is when I start having problems.
_CLKMODE = XTAL1 + PLL16X _XINFREQ = 5_000_000 var long comm_stack long timer OBJ ser : "fullduplexserial" PUB Main timer:=0 cognew(@counter_plus, @timer) cognew(@counter_minus, @timer) cognew(@io, @timer) cognew(comms, @comm_stack) pub comms | i ser.start(31, 30, 0, 1000000) repeat ser.dec(timer) ser.tx(13) waitcnt(clkfreq/2000 +cnt) DAT org 0 counter_plus mov t2, par mov dira, #0 :loop waitpeq pin_a_mask, pin_a_mask rdlong t1, t2 cmp t1, #0 wz if_always add t1, #1 wrlong t1, t2 jmp #:loop pin_a_mask long 1 t1 res 1 t2 res 1 'zero long 0 DAT org 0 counter_minus mov t4, par mov dira, #0 :loop waitpeq pin_b_mask, pin_b_mask rdlong t3, t4 cmp t3, #0 wz if_always sub t3, #1 wrlong t3, t4 jmp #:loop pin_b_mask long 1 << 1 t3 res 1 t4 res 1 DAT org 0 io mov t5, par mov dira,io_mask :loop rdlong t6, t5 cmps time3, t6 wc if_c mov outa, io_3 if_c jmp #:loop if_nc cmps time2, t6 wc if_c mov outa, io_2 if_c jmp #:loop if_nc cmps time1, t6 wc if_c mov outa, io_1 if_c jmp #:loop if_nc mov outa, io_0 jmp #:loop io_mask long %11111111_00000000_00000000 io_0 long %00000000_00000000_00000000 io_1 long %00000001_00000000_00000000 io_2 long %00000011_00000000_00000000 io_3 long %00000111_00000000_00000000 time1 long 15000 time2 long 50000 time3 long 86000 t5 res 1 t6 res 1 t7 res 1