AMIS-30621 LIN Micro-stepping Motor Driver
Data Sheet
12.5.1. Position Ranges
A position is coded by using the binary two’s complement format. According to the positioning commands used and to the chosen
stepping mode, the position range will be as shown in Table 11.
Table 11: Position Range
Command
Stepping Mode
Half-stepping
Position Range
-4096 to +4095
-8192 to +8191
-16384 to +16383
-32768 to +32767
-1024 to +1023
Full Range Excursion
8192 half-steps
16384 micro-steps
32768 micro-steps
65536 micro-steps
2048 half-steps
Number of Bits
13
14
15
16
11
1/4th micro-stepping
1/8th micro-stepping
1/16th micro-stepping
Half-stepping
SetPosition
SetPositionShort
When using the command SetPosition, although coded on 16 bits, the position word will have to be shifted to the left by a certain
number of bits, according to the stepping mode.
12.5.2. Secure Position
A secure position can be programmed. It is coded in 11-bits, thus having a lower resolution than normal positions, as shown in
Table 12. See also command GotoSecurePositionand LIN Lost Behavior.
Table 12: Secure Position
Stepping Mode
Half-stepping
Secure Position Resolution
4 half-steps
1/4th micro-stepping
1/8th micro-stepping
1/16th micro-stepping
Important Notes:
8 micro-steps (1/4th)
16 micro-steps (1/8th)
32 micro-steps (1/16th)
(1) The secure position is disabled in case the programmed value is the reserved code “10000000000” (0x400 or most negative position).
(2) After start-up the OTP register is copied in RAM as illustrated below.
RAM
OTP
SecPos10
SecPos10
SecPos9
SecPos9
SecPos8
SecPos8
SecPos2
SecPos2
SecPos1
SecPos1
SecPos0
SecPos0
12.5.3. Shaft
A shaft bit which can be programmed in OTP or with command SetMotorParam,defines whether a positive motion is a clockwise or
counter-clockwise rotation (an outer or an inner motion for linear actuators):
• Shaft = 0 ⇒ MOTXP is used as positive pin of the X coil, while MOTXN is the negative one.
• Shaft = 1 ⇒ opposite situation.
AMI Semiconductor – Sept. 2007, Rev 1.5
13
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