Subject:
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Re: DC output at motor max speed with legOS
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Tue, 6 Feb 2001 17:23:58 GMT
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Viewed:
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1321 times
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On Feb 6, Athan Kostakos wrote:
> Hi, I am trying to control a stepper motor with LegOS, and I need to have a
> constant DC output from a motor output, like when I choose speed(8) with the
> Lego firmware, so I can turn it on and off to make pulses of the duration I
> choose.
> Is this possible?
So motor_a_speed(MAX_SPEED) is not enough, since it turns the motor
off every 256 ms for a single ms?
I have an idea how to change the code to make the output really
constant, patch attached. A side-effect of this change is that
motor_a_speed(MIN_SPEED) is not turning the motor completely off, but
this is the purpose of motor_a_dir(off).
You have to recompile the kernel AND your programs. Does this patch
work for you?
Jochen
diff -u -r1.3 dmotor.h
--- include/dmotor.h 2000/08/16 09:45:10 1.3
+++ include/dmotor.h 2001/02/06 16:53:12
@@ -140,7 +140,7 @@
*/
extern const inline void motor_a_speed(unsigned char speed)
{
- dm_a.access.c.delta = speed;
+ dm_a.access.c.delta = ~speed;
}
//! set motor B speed
@@ -148,7 +148,7 @@
*/
extern const inline void motor_b_speed(unsigned char speed)
{
- dm_b.access.c.delta = speed;
+ dm_b.access.c.delta = ~speed;
}
//! set motor C speed
@@ -156,7 +156,7 @@
*/
extern const inline void motor_c_speed(unsigned char speed)
{
- dm_c.access.c.delta = speed;
+ dm_c.access.c.delta = ~speed;
}
#endif // CONF_DMOTOR
===================================================================
RCS file: /cvsroot/legOS/legOS/kernel/dmotor.c,v
retrieving revision 1.2
diff -u -r1.2 dmotor.c
--- kernel/dmotor.c 2000/08/16 09:45:11 1.2
+++ kernel/dmotor.c 2001/02/06 16:53:12
@@ -89,7 +89,7 @@
mov.w @_dm_a,r0
add.b r0h,r0l ; add delta to sum
- bcc dm0 ; sum overflow?
+ bcs dm0 ; sum overflow?
mov.b @_dm_a+2,r6h ; -> output drive pattern
xor.b r6h,r6l
dm0:mov.b r0l,@_dm_a+1 ; save sum
@@ -99,7 +99,7 @@
mov.w @_dm_b,r0
add.b r0h,r0l ; add delta to sum
- bcc dm1 ; sum overflow?
+ bcs dm1 ; sum overflow?
mov.b @_dm_b+2,r6h ; -> output drive pattern
xor.b r6h,r6l
dm1:mov.b r0l,@_dm_b+1 ; save sum
@@ -109,7 +109,7 @@
mov.w @_dm_c,r0
add.b r0h,r0l ; add delta to sum
- bcc dm2 ; sum overflow?
+ bcs dm2 ; sum overflow?
mov.b @_dm_c+2,r6h ; -> output drive pattern
xor.b r6h,r6l
dm2:mov.b r0l,@_dm_c+1 ; save sum
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