Reference Manual

Turbo PMAC/PMAC2 Software Reference
Turbo PMAC Global I-Variables 213
Each Servo IC has four channels of servo interface circuitry, numbered IC channels 1 to 4. In the I-
variable numbering scheme, the IC channel number determines the 10’s digit of the I-variable number,
represented by the letter ‘n’ to refer to any channel generally (e.g. I7mn3).
For even-numbered Servo ICs 0, 2, 4, 6, and 8, the channel numbers 1 – 4 on the IC match the channel
numbers 1 – 4 on the board. For odd-numbered Servo ICs 1, 3, 5, 7, and 9, which require the presence of
Option 1 on the board, the IC channel numbers 1 – 4 correspond to board channel numbers 5 – 8,
respectively.
The following table shows key data about each potential Servo IC in the system:
Servo
IC #
Board
Board
Channel #s
I-Variables
Base
Address
Default
Assignment
0
Turbo PMAC
1 – 4
I7000 – I7049
$078000
Motors 1-4
1
Turbo PMAC
5 – 8
I7100 – I7149
$078100
Motors 5-8
2
First Acc-24
1 – 4
I7200 – I7249
$078200
Motors 9-12
3
First Acc-24
5 – 8
I7300 – I7349
$078300
Motors 13-16
4
Second Acc-24
1 – 4
I7400 – I7449
$079200
Motors 17-20
5
Second Acc-24
5 – 8
I7500 – I7549
$079300
Motors 21-24
6
Third Acc-24
1 – 4
I7600 – I7649
$07A200
Motors 25-28
7
Third Acc-24
5 – 8
I7700 – I7749
$07A300
Motors 29-32
8
Fourth Acc-24
1 – 4
I7800 – I7849
$07B200
none
9
Fourth Acc-24
5 – 8
I7900 – I7949
$07B300
none
Note:
Some new accessory boards for the UMAC 3U-format Turbo PMAC employ
alternate addressing of Servo ICs, labeled Servo ICs 2* through 9*. Servo IC m*
is controlled by I-variables numbered 50 higher than Servo IC m,(e.g. I7250 –
I7299 for Servo IC 2*) and is addressed $20 higher (e.g. $078220 for Servo IC
2*).
PMAC2-Style Multi-Channel Servo IC I-Variables
I-variables in the range I7m00 to I7m09 control global and multi-channel aspects of the hardware setup
using the first “DSPGATE1” Servo IC on the Turbo PMAC2. On Turbo PMAC2 Ultralite boards, there
are no DSPGATE1 Servo ICs on board, so these functions are implemented in the DSPGATE2 ASIC,
which is controlled by variables in the I6800s.
I7m00 Servo IC m MaxPhase/PWM Frequency Control
Range: 0 - 32767
Units: MaxPhase Frequency = 117,964.8 kHz / [2*I7m00+3]
PWM Frequency = 117,964.8 kHz / [4*I7m00+6]
Default: 6527
MaxPhase Frequency = 117,964.8 / 13057 = 9.0346 kHz
PWM Frequency = 117,964.8 / 26114 = 4.5173 kHz
I7m00 controls the internal MaxPhase clock frequency, and the PWM frequency for the four machine
interface channels, on PMAC2-style Servo IC m (m = 0 to 9). The internally generated Phase and Servo
clocks on Servo IC m are derived from the MaxPhase clock.
If the Servo IC is used to generate the Phase and Servo clocks for the PMAC system (as set by I19 and
the I7m07 variables), this variable is part of the control for the frequency of these system clocks.