Delta Tau GEO BRICK LV User Manual
Geo Brick LV User Manual
PinOuts and Software Setup
138
Setting up the Analog (DAC) Outputs
Differential DAC Output Signal
Single Ended DAC Output Signal
2
3
4
5
9
8
7
6
1
AGND
Analog
Device
DAC+
DAC-
2
3
4
5
9
8
7
6
1
AGND
Analog
Device
DAC+
The analog outputs on X9 through X12 are (12-bit) filtered PWM signals, therefore a PWM frequency in
the range of 30-40 KHz and a PWM deadtime of zero are suggested for a good quality analog output
signal (minimized ripple). A fully populated Brick can have one of three gates generating the clocks:
Servo IC 0 (I7000’s)
Servo IC 1 (I7100’s)
MACRO IC 0 (I6800’s)
I19 specifies which gate is the clock source master. I19 is equal to 7007 by default indicating that Servo
IC 0 is the master gate. However, the analog outputs on X9 through X12 are generated out of Servo IC1.
IC 0 is the master gate. However, the analog outputs on X9 through X12 are generated out of Servo IC1.
The relationship between the PWM clock frequency of Servo IC 1 (recipient) and the master gate
(generator), typically Servo IC 0, should always be respected in such a way that:
Where n is an integer
Example:
With Servo IC 0 sourcing the clock at its’ recommended settings (20 KHz PWM), the following are
suggested MACRO IC 0 clock settings which would provide a good analog output signal:
With Servo IC 0 sourcing the clock at its’ recommended settings (20 KHz PWM), the following are
suggested MACRO IC 0 clock settings which would provide a good analog output signal:
Servo IC 0
Clock Settings
Resulting
Frequencies KHz
Servo IC 1
Clock Settings
Resulting
Frequencies KHz
I7000=1473
I7001=0
I7002=7
I7002=7
I10=1677653
PWM
PHASE
SERVO
20
40
40
5
I7100=735
I7101=3
I7102=3
I7104=0
I7102=3
I7104=0
PWM
PHASE
SERVO
PWM
PHASE
SERVO
PWM
Deadtime
40
20
20
5
0
0
Note that n=2 in this case