AD9992_07 AD [Analog Devices], AD9992_07 Datasheet - Page 51

• Manufacturer Part Number: AD9992_07
• Description: 12-Bit CCD Signal Processor with Precision Timing Generator
• Manufacturer: AD [Analog Devices]

GENERAL-PURPOSE OUTPUTS (GPOS)
The AD9992 provides programmable outputs to control a
mechanical shutter, strobe/flash, the CCD bias select signal, or
any other external component with general-purpose (GP)
signals. Eight GP signals, with up to four toggles each, are
available that can be programmed and assigned to special GPO
pins. These pins are bidirectional and allow visibility (as an output)
and external control (as an input) of HBLK, PBLK, CLPOB, and
OUTCONTROL. The registers introduced in this section are
described in Table 23.
GP Toggles
When configured as an output, each GPO1 to GPO8 output can
deliver a signal that is the result of programmable toggle positions.
The GP signals are independent and can be linked to either
a specific VD period or over a range of VD periods via the primary
or secondary field counters through the GP protocol registers
(Address 0x73). As a result of their associations with the field
counters, the GP toggles inherit the characteristics of the field
counters, such as RapidShot and ShotDelay.
To use the GP toggles,
1.
2.
3.
4.
Program the toggle positions (Address 0x7A to
Address 0xA9).
Program the protocol (Address 0x73).
Program the counter parameters (Address 0x71 to
Address 0x72).
Activate the counter (Address 0x70).
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For Protocol 1 (no counter association), skip Step 3 and Step 4.
With these four steps, the GP signals can be programmed to
accomplish many common tasks. Careful protocol selection and
application of the field counters yields efficient results to allow
the GP signals smooth integration with concurrent operations.
Note that the SUBCK and VSG masks are linked to the primary
counter; however, if their parameters are 0, the GPO can use
the primary counter without expose/read activity.
The secondary counter is independent and can be used
simultaneously with the primary counter. Some applications
may require the use of both primary and secondary field
counters with different GPO protocols, start times, and
durations. Such operations are easily handled by the AD9992.
Several simple examples of GPO applications using only one
GPO and one field counter follow. These examples can be used
as building blocks for more complex GPO activity. In addition,
specific GPO signals can be passed through a 4-input LUT to
realize combinational logic between them. For example, GP1
and GP2 can be sent through an XOR look-up table, and the result
can be delivered on GP1, GP2, or both. Also, either GP1 or GP2
can deliver their original toggles.
AD9992