Problem with Servo Driver using DT_INST-14/TimerTemplate
This is another attempt to create a servo driver based on instant interrupts. This one almost works, but not quite. I may attempting the imposible; if so, could someone please tell me. I really don't know how to interpret assembly routines.
This servo driver is based on Darrel Taylor's DT_INTS-14/TimerTemplate which can be found on this Forum. It is easy to set up a 50 hz interrupt to start and repeat standard servo frames. In addition to running a servo I'm driving a brushless motor controller, which also runs on standard servo frames. Testing is done with real hardware, including a motor, controller, and servo.
The routine shown below works as long as I do not attempt to change the motor drive pulses from full on to full off. The motor actually starts and runs at full speed. However, in order to stop the motor it is necessary to apply full off pulses. When I attempt to do this the program somehow scans through and picks up the full off setting, and applies this to the whole sequence. The result is that the motor will not start.
Most of the code shown is just a copy of the TimerTemplate. I added the interrupt handler and the few lines in the main section.
Code:'device is PIC 16F684 'set registers '...done... DEFINE OSC 8 '8 Mhz oscillator 'declare variables '....done... ' initialize ports and variables portc.1 = 0 'turn off servo portc.4 = 0 'initialize servo pulse low portc.5 = 0 'initialize throttle pulse low throttlepos = 400 '2*(200) = full throttle servopos = 300 '2*(150) = mid range of servo MTtime = 100 '10.0 second motor run time BKtime = 15 '1.5 second brake time ticks = 0 '0.02 seconds per tick tenths = 0 '1/10 seconds seconds = 0 'seconds sum = 0 'total time in tenths, e.g. 100 = 10.0 sec. 'arm the motor 'Phoenix-10 brushless motor controller requires throttle-off arming 'for 4 seconds '....done... INCLUDE "DT_INTS-14 for F684.bas" ; Base Interrupt System with wsave for F684 INCLUDE "ReEnterPBP.bas" ; Include if using PBP interrupts ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler TMR1_INT, ReloadTMR1, ASM, no ; MUST be first INT_Handler TMR1_INT, _T1handler, PBP, yes endm INT_CREATE ; Creates the interrupt processor ENDASM ;--- Match the desired interrupt frequency ------------------- ;--- See http://DarrelTaylor.com/DT_INTS-14/TimerTemplate.html for more Info. @Freq = 50 ; 50 Hz Frequency of Interrupts @Prescaler = 1 ; Timers Prescaler setting T1CON = $00 ; $00 = Prescaler 1:1, TMR1 OFF @ INT_ENABLE TMR1_INT ; enable Timer 1 interrupts GOSUB StartTimer ; Start the Timer portc.1 = 1 'turn on servo power low Led 'turn on led Main: ; ---- Your Main Program goes here ---- if sum => MTtime then 'motor fully on for 10.0 seconds high led 'turn off led .. this signals end of motor run goto newtime1 'try to reset throttle to full off endif newtime1: ' brake motor for 1.5 seconds ' throttlepos = 200 ' 2*(100) throttle full off; brake on. This is 'the problem line. Does not work when uncommented if sum => (MTtime + BKtime) then 'motor off, braking done low led 'turn on led; signals end of braking goto DT endif GOTO Main '------------------------------------------- DT: @ INT_DISABLE TMR1_INT ; disable Timer 1 interrupts portc.1 = 0 'turn off servo end 'sleep until next power on cycle ;____This routine is Called on each TMR1 Interrupt____________________________ T1handler: 'interrupts are every 20 ms. These interrupts start each servo frame 'and also clock elapsed time. pulsout portc.5,throttlepos 'send pulse to motor speed controller pulsout portc.4,servopos 'send pulse to servo (pulse range is Ticks = Ticks + 1 '1 ms to 2 ms for both pulses) if Ticks = 5 then Ticks = Ticks - 5 Tenths = Tenths + 1 if tenths = 10 then Seconds = Seconds + 1 Tenths = 0 endif sum = 10*Seconds + Tenths 'calculate time in tenths of seconds endif ; ---- ---------------------------------- ---- @ INT_RETURN ;---[TMR1 reload - interrupt handler]----------------------------------------- ASM ; Calculate Timer Reload Constant ReloadInst = 8 ; # of Intructions used to reload timer if ((Prescaler == 1)||(Prescaler == 2)||(Prescaler == 4)||(Prescaler == 8)) MaxCount = 65536 + (ReloadInst / Prescaler) TimerReload = MaxCount - (OSC*1000000/4/Prescaler/Freq) if ((TimerReload < 0) || (TimerReload > (65535-ReloadInst))) error Invalid Timer Values - check "OSC", "Freq" and "Prescaler" endif else error Invalid Prescaler endif ENDASM @Timer1 = TMR1L ; map timer registers to a word variable Timer1 VAR WORD EXT TimerReload CON EXT ; Get the External Constant TMR1ON VAR T1CON.0 ; Alias the Timers ON/OFF bit ;---Reload Timer1------ ASM ReloadTMR1 MOVE?CT 0, T1CON, TMR1ON ; 1 stop timer MOVLW LOW(TimerReload) ; 1 Add TimerReload to the ADDWF TMR1L,F ; 1 value in Timer1 BTFSC STATUS,C ; 1/2 INCF TMR1H,F ; 1 MOVLW HIGH(TimerReload) ; 1 ADDWF TMR1H,F ; 1 MOVE?CT 1, T1CON, TMR1ON ; 1 start timer INT_RETURN ENDASM ;---Start/Stop controls ----- StartTimer: Timer1 = TimerReload ; Load Timer TMR1ON = 1 ; start timer RETURN StopTimer: TMR1ON = 0 ; stop timer RETURN
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