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Power Brick Controller User Manual
Connections and Software Setup 84
Setting up the Analog (DAC) Outputs
The analog outputs provide ±10 VDC signals interfacing to either differential or single-ended devices.
Differential DAC Output Signal Single Ended DAC Output Signal
This analog output circuitry is filtered PWM optimized (in hardware) for a PWM cut off frequency of about
15 kHz. The recommended PWM frequency of 10 kHz in the Power Brick Controller should be good
enough for general purpose usage.
Note
These analog outputs are synthesized filtered PWM. They are
designed for general purpose use; they are not industrially graded for
servo use. True DAC outputs are typically used in servo applications.
The analog output command data resides in the upper 16 bits of the 32-bit structure element
PowerBrick[ i ].Chan[ j ].PWM[3]. The structure elements do not allow bit masking (of the upper 16 bits),
hence scaling (shifting) is required to write to the outputs properly. Using the explicit address registers
makes it easier for bit masking:
Channel /
Connector
Address
Channel /
Connector
Address
Channel 1, X9 $90004C Channel 1, X11 $90404C
Channel 2, X9 $9000CC Channel 2, X11 $9040CC
Channel 1, X10
$90014C Channel 1, X12 $90414C
Channel 2, X10 $9001CC Channel 2, X12 $9041CC
Note
The explicit address register(s) can be found by subtracting
PowerBrick[ i ].Chan[ j ].PWM[3].a from Sys.piom .
AGND
Analog
Device
5
4
3
2
1
10
15
9
8
7
6
14
13
12
11
5
4
3
2
1
10
9
8
7
6
15
14
13
12
11