PASM: Can I add/sub/cmp on FRQA/B??
Alex.Stanfield
Posts: 198
The Propeller manual states that FRQA can be used as any other regular register, however I'm apparently seeing different behavior in PASM on FRQA when using it in ADD, SUB or CMP statements.
Any experience on this?
Alex
Any experience on this?
Alex
Comments
-Phil
Here's the routine that troubles me, if you un-comment the first and last 'mov' statements (with sFRQA) and replace FRQA with sFRQA in the in-between statements the routine gets to the "_Running" phase with the same parameters, as it's now it jumps from "_Starting " to "_Stopping"
Thanks for taking a look
Mon_JOB mov wphsb, PHSB 'Save current value for PHSB mov qsteps, wphsb sub qsteps, lst_phsb WZ 'Get number of steps elapsed if_z jmp #Mon_JOB_ret 'No change -> exit mov lst_phsb, wPHSB 'Save for next checking '***Step ocurred so adjust position and check job boundaries--------------------- mov dsteps, qsteps test pn, #$100 WZ 'Z=1 if pn positive if_nz neg dsteps, dsteps '***Inc/Dec motor position------------------------------------------------------- updpos adds 0-0, dsteps 'pn 'Update motor pos sub cs_Steps2Go,qsteps WC,WZ'Decrement pending steps if_be mov FRQA, #0 'Stop Pulses ' if_be mov PHSA, #0 'De-assert clk line if_be mov cs_Steps2Go, #0 'Catch overflows (excess steps) if_be jmp #:exit 'Get out & reset job ' '***Check job boundaries--------------------------------------------------------- ' mov sFRQA, FRQA '************************************************************************************************* :Chk_Starting cmp cs_motSts, #_Starting WZ'*** STARTING PHASE ****************************** if_ne jmp #:Chk_Running add Nramp, qsteps 'Add steps in ramp (used in STOP command) mov t1, nxt_1ms 'Check if 1msec elapsed sub t1, cnt cmps t1, #0 WC 'C=1 if time is up if_nc jmp #:SkipFStart add nxt_1ms, _1ms 'Set next period add FRQA, Ramp_1ms 'Acc change to FRQA maxs FRQA, FRQ_max WC if_c jmp #:SkipFStart 'Max speed NOT reached, get out mov cs_motSts, #_Running 'Change state to Running mov N2, pstep sub N2, Nramp 'Nramp updated in "Mon_JOB" :SkipFStart cmp wPHSB, N2 WC,WZ 'Got to stopping phase? if_ae mov cs_motSts, #_Stopping '=> go directly to stopping phase if_ae mov nxt_1ms, _1ms if_ae add nxt_1ms, cnt '************************************************************************************************* :Chk_Running cmp cs_motSts, #_Running WZ'*** RUNNING PHASE ******************************* if_ne jmp #:Chk_Stopping tjnz sv_run, #:exit 'if RUN in progress keep running cmp wPHSB, N2 WC,WZ 'Got to stopping phase? if_ae mov cs_motSts, #_Stopping '=> go directly to stopping phase if_ae mov nxt_1ms, _1ms if_ae add nxt_1ms, cnt '************************************************************************************************* :Chk_Stopping cmp cs_motSts, #_Stopping WZ'*** STOPPING PHASE ****************************** if_ne jmp #:Exit mov t1, nxt_1ms 'Check if 1msec elapsed sub t1, cnt cmps t1, #0 WC 'C=1 if time is up if_nc jmp #:SkipFStop add nxt_1ms, _1ms 'Set next period sub FRQA, Ramp_1ms 'Acc change to FRQA mins FRQA, FRQ_min :SkipFStop '****Slowing down then keep running when fmax reached------------------------------------- test flags, #_f_slowdown WZ 'Are we slowing down after a _NewSpeed? if_z jmp #:skip_slowdown cmp FRQA, FRQ_max WC,WZ if_be mov cs_motSts, #_Running 'Go back to running phase since we reached the 'slowdown limit after _NewSpeed if_be andn flags, #_f_slowdown 'Reset flag for slowdown if_be jmp #:Exit :skip_slowdown '**** If job was STOPPED then slowdown until fmin and then stop -------------------------- test flags, #_f_stop WZ if_z jmp #:skip_stop cmp FRQA, FRQ_min WC,WZ 'Cancel motion when Fmin reached if_be mov FRQA, #0 'Reset job when we get to the main loop if_be mov cs_Steps2Go, #0 ' if_be mov PHSA, #0 'de-assert clk line :skip_stop ' sub Nramp, #1 WZ 'Decrease ramp steps (used in STOP command) ' mins Nramp, #0 WC 'Limit Nramp to 0 or greater ' if_z_or_c mov FRQA, #0 'Stop job '**** EXIT section------------------------------------------------------------------------ :Exit tjnz cs_Steps2go, #Mon_JOB_ret1 chkpos test 0-0, Scale_msk WZ 'Finished on fullstep boundary? if_nz add cs_Steps2go, #1 'NO->add 1 more step if_nz mov FRQA, FRQ_min 'Set fmin for remaining steps Mon_JOB_ret1 ' mov FRQA, SFRQA Mon_JOB_ret retAlex
sub FRQA, Ramp_1ms 'Acc change to FRQA mins FRQA, FRQ_minwill affect phsa after each step if the counter is running. That might not be the behavior that you want or expect.
-Phil
Agreed, but it doesn't matter in this case, those max/min statements are just to keep the upper/lower limits, and at the operating frequency it's not noticeable.
Alex