Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 205
I68n2 and I69n2 determine which input signal or combination of signals, and which polarity, for Channel
n* (n* = 1 to 2) on a DSPGATE2 MACRO IC triggers a hardware position capture of the counter for
Encoder n*. For MACRO ICs 0 and 2, n = n*; for MACRO ICs 1 and 3, n = n* + 5 (i.e. I6812 controls
MACRO IC 0 Channel 1; I6972 controls MACRO IC 3 Channel 2). If a flag input (home, limit, or user)
is used, I68n3/I69n3 determines which flag. Proper setup of this variable is essential for a successful
homing search move or other move-until-trigger for the Motor xx using Channel n* for its position-loop
feedback and flags if the super-accurate hardware position capture function is used. If Ixx97 is at its
default value of 0 to select hardware capture and trigger, this variable must be set up properly.
The following settings of I68n2 may be used:
 I68n2 = 0: Continuous capture
 I68n2 = 1: Capture on Index (CHCn) high
 I68n2 = 2: Capture on Flag n high
 I68n2 = 3: Capture on (Index high AND Flag n high)
 I68n2 = 4: Continuous capture
 I68n2 = 5: Capture on Index (CHCn) low
 I68n2 = 6: Capture on Flag n high
 I68n2 = 7: Capture on (Index low AND Flag n high)
 I68n2 = 8: Continuous capture
 I68n2 = 9: Capture on Index (CHCn) high
 I68n2 = 10: Capture on Flag n low
 I68n2 = 11: Capture on (Index high AND Flag n low)
 I68n2 = 12: Continuous capture
 I68n2 = 13: Capture on Index (CHCn) low
 I68n2 = 14: Capture on Flag n low
 I68n2 = 15: Capture on (Index low and Flag n low)
Only flags and index inputs of the same channel number as the encoder may be used for hardware capture
of that encoder’s position. This means that to use the hardware capture feature for the homing search
move, Ixx25 must use flags of the same channel number as the encoder that Ixx03 uses for position-loop
feedback.
The trigger is armed when the position capture register is read. After this, as soon as the MACRO IC
hardware sees that the specified input lines are in the specified states, the trigger will occur -- it is level-
triggered, not edge-triggered.
Note:
By default, the index-channel and flag inputs of a MACRO IC are not used on a
Turbo PMAC2. The index inputs and flag inputs are alternate uses of pins on the
Multiplexer and I/O ports, respectively.
I68n3/I69n3 MACRO IC Channel n* Capture Flag Select Control
Range: 0 - 3
Units: none
Default: 0
Note:
This I-variable is active only if the MACRO IC is present, and is a DSPGATE2 IC.
The presence and type of MACRO ICs are reported in I4902 and I4903.