using MicroCore11 instead of Remote Control to Scorpion(motor controller) | M68HC11

Recently i am using MicroCore11(68HC11) instead of remote control to generate PWM(pulse wide modulation) to Scorpion(a motor controller from robot-power) to control the motors. However i am unable to generate the correct pulse (but instead i have square waves),and the motor can't move. When i use function generator to generate pulse to the Scorpion, the motor can move. I am no using assemble language. Any kind soul can give advice or relevant program to use. Thanks :) ivy

(You need to be a member of hc11 -- send a blank email to hc11-subscribe@yahoogroups.com )

This is a recall of a previous answer to a similar question, I hope it can help. Here it goes: I bet you are trying to control a Hobby type servo motor's position. It is relatively easy to generate pulses with the HC11 . Please find below the assembly routine to have OC2, OC3, OC4 and OC5 generate pulses continuously. You run the routine once, and the OCx will take care of the pulse generation indefinitely. If you want a pulse duration to change, simply change the TOCx value. This is great ! Your MPU could spend more time on your control algorithm. The following duration table below also show the TOCx values for servo position from -90 degrees to + 90 degrees, according to my experience. But this can change with different servo manufacturers. Serinit ldx #REGBASE ; X points to the registers base (= $1000 ?) ldaa #%10101010 ;OMx =1, OLx=0 staa TCTL1,x ;Initiate TCTL1 to clear OC2, OC3, OC4, OC5 pins on succesfull compare (Pink Book p10-31) clr TCTL2,x ;Clear TCTL2 ldaa #%01111000 ;OC1M6..OC1M3=1 staa OC1M,x ;Initiate mask OC1Mx to enable portA pins 6 to 3. (pink Book p10-33) staa OC1D,x ;Initiate data OC1Dx ldd #$A00 ;Center position of each servos (Futaba s148,s132). std TOC2,x ; servo S1 on Botboard + std TOC3,x ; S2 std TOC4,x ; S3 std TOC5,x ; S4 TOCx duration table with 8Mhz cristal, E = 2Mhz: $1200= 4608, -90 degrees, T= 2.304ms $E00 = 3584, -45 degrees, T= 1.792ms $A00 = 2560, center position, T= 1.28ms $600 = 1536, +45 degrees, T= 0.768ms $200 = 512, +90 degrees, T= 0.256ms The pulse period is equal to the free running counter roll over period = 65,536 x 0,5 usec = 32,765 usec or 32.7 msec. This should be short enough to keep your servo awakened. If you want to connect your Radio Control receiver to the HC11, it is possible to use the Input Capture channels to measure the incoming pulse width. I use this to move my robot when it gets stuck in a corner. This is done using interrupt capability of the IC, but this is a different story. if you want to know how, e-mail personaly. No interrupt service routines are needed to control servos with Output Compare channels. I hope this helps Kind regards Jean ----- Original Message ----- From: "senglee88" <> To: <> Sent: Wednesday, December 01, 2004 9:22 AM Subject: [m68HC11] using MicroCore11 instead of Remote Control to Scorpion(motor controller) > > > Recently i am using MicroCore11(68HC11) instead of remote control to > generate PWM(pulse wide modulation) to Scorpion(a motor controller > from robot-power) to control the motors. However i am unable to > generate the correct pulse (but instead i have square waves),and the > motor can't move. > > When i use function generator to generate pulse to the Scorpion, the > motor can move. > > I am no using assemble language. > > Any kind soul can give advice or relevant program to use. > > Thanks :) > > ivy > > Yahoo! Groups Links

(You need to be a member of hc11 -- send a blank email to hc11-subscribe@yahoogroups.com )

Sign in

Search hc11

Subscribe to hc11

Ads

Discussion Groups

Discussion Groups | M68HC11 | using MicroCore11 instead of Remote Control to Scorpion(motor controller)

using MicroCore11 instead of Remote Control to Scorpion(motor controller) - senglee88 - Dec 1 9:22:00 2004

Re: using MicroCore11 instead of Remote Control to Scorpion(motor controller) - Jean St-Pierre - Dec 3 23:42:00 2004