DESCRIPTION OF THE CCD VIDEO BOARDs
The Video board contains the DACS to generate the CCD bias voltages such as OD, RD, OG etc.. The table below shows the range of each bias DAC channel, its address and its output impedance. The DAC value controlling each channel can vary from &000 to &FFF. Because of the different ranges of the channels, writing the same byte to DAC on different channels can have different effects. As an example let us assume that the Video board in use is board 0 (set by links on the board). If we were to send &FFF (i.e DAC full range) to the DAC controlling Pin 2, we would have to write the byte &0D4FFF, pin 2 would then output 30V. If we were to send &FFF to the DAC controlling pin 8, we would have to write the byte &0ECFFF, pin8 in this case would output 20V.
SDSU Video Board Connector |
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output impedance |
Voltage Range |
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Pin number on 25 Way connector |
Type |
address |
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1 |
BIAS |
xD0xxx |
100R |
7.5-30 |
2 |
BIAS |
xD4xxx |
100R |
7.5-30 |
3 |
BIAS |
xD8xxx |
1K |
5-20 |
4 |
BIAS |
xDCxxx |
1K |
5-20 |
5 |
BIAS |
xE0xxx |
1K |
5-20 |
6 |
BIAS |
xE4xxx |
1K |
5-20 |
7 |
BIAS |
xE8xxx |
1K |
5-20 |
8 |
BIAS |
xECxxx |
1K |
5-20 |
9 |
BIAS |
xF0xxx |
1K |
+/- 5 |
10 |
BIAS |
xF4xxx |
1K |
+/- 5 |
11 |
BIAS |
xF8xxx |
1K |
+/-10 |
12 |
BIAS |
xFCxxx |
1K |
+/-10 |
22 |
GND |
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Last Updated on 4/20/01
By smtport