PMAC/PMAC2 V1.17C Addendum I9n9 Channel n Hardware-1/T Control [New, PMAC2 only] Range: 0 – 1 Units: none Default: 0 I9n9 controls whether the “hardware-1/T” functionality is enabled for a PMAC2 Servo IC on Channel n. If I9n9 is set to the default value of 0, the hardware-1/T functionality is disabled, permitting the use of the “software-1/T” position extension that is calculated by default with encoder conversion method $0. If I9n9 is set to 1, the hardware-1/T functionality is enabled (if present on the IC), and the software-1/T cannot be used. The hardware-1/T functionality is present only on Revision D and newer of the PMAC2-style DSPGATE1 IC, released at the beginning of the year 2002.
Setting I9n9 to 1 on an older revision IC does nothing – software-1/T functions can still be used. When the hardware-1/T functionality is enabled, the IC computes a new fractional-count position estimate based on timers every SCLK (encoder sample clock) cycle. This permits the fractional count data to be used for hardware capture and compare functions, enhancing their resolution. This is particularly useful when the IC is used on an ACC-51 high-resolution analog-encoder interpolator board.
However, it replaces the timer registers at the first two “Y” addresses for the channel with fractional count position data, so the traditional software-1/T method of the conversion table cannot work if this is enabled. If you enable the hardware-1/T functionality, and want to be able to use 1/T interpolation in your servo loop, you must use the hardware-1/T extension method ($C method digit with the mode switch bit set to 1) in the encoder conversion table. I1010 Resolver Excitation Phase Offset [New, Geo PMAC only] Range: 0 – 255 Units: 1/256 cycle Default: 0 I1010 specifies the phase (time) offset for the AC excitation created by the Geo PMAC for resolvers.
The optimum setting of I1010 depends on the L/R time constant of the resolver circuit. I1010 should be set interactively so as to maximize the magnitudes of the feedback ADC values (Y:$FF00 and Y:$FF01 for Resolver 1; Y:$FF20 and Y:$FF21 for Resolver 2). I1010 is only used if the Geo PMAC’s Feedback Option 1 for analog position feedback is ordered. V1.17C Firmware Version 9