AD9927 Analog Devices, AD9927 Datasheet - Page 74

• Manufacturer Part Number: AD9927
• Description: 14-Bit CCD Signal Processor
• Manufacturer: Analog Devices

AD9927
Table 45. Power-Up Register Write Sequence
Address
0x10
0x26
0x20 to
0xFFF
0xD8
0x00
0x15
0x14
0x20
0x11
0x1C
0x13
Using the SWSYNC Register
If an external SYNC pulse is not available, it is possible to
generate an internal SYNC in the AD9927 by writing 1 to the
SWSYNC register (Address 0x13, Bit [14]). If the software SYNC
option is used, the SYNC input (Pin D3) should be low (V
during power-up. The SYNCENABLE register (Address 0x13,
Bit [0]) should be set high.
SYNC During Master Mode Operation
The hardware SYNC input can be used anytime during
operation to synchronize the AD9927 counters with external
timing, as shown in Figure 88. The operation of the digital
outputs can be suspended during the SYNC operation by
setting the SYNCSUSPEND register (Address 0x13, Bit [2]) to 1.
If SYNCSUSPEND = 1, the polarities of the outputs are held at
the same state as OUTCONTROL = low, as shown in Table 46.
H1 TO H4, RG,
XV1 TO XV24,
VSG, SUBCK
NOTES
1. THE SYNC RISING EDGE RESETS VD/HD AND COUNTERS TO 0.
2. SYNC POLARITY IS PROGRAMMABLE USING SYNCPOL REGISTER (ADDR 0x13).
3. DURING SYNC LOW, ALL INTERNAL COUNTERS ARE RESET AND VD/HD CAN BE SUSPENDED USING THE SYNCSUSPEND REGISTER (ADDR 0x13).
4. IF SYNCSUSPEND = 1, VERTICAL CLOCKS, H1 TO H4, AND RG ARE HELD AT THE SAME POLARITY SPECIFIED BY OUTCONTROL = LOW.
5. IF SYNCSUSPEND = 0, ALL CLOCK OUTPUTS CONTINUE TO OPERATE NORMALLY UNTIL THE SYNC RESET EDGE.
0x01
User-
defined
User-
defined
0x888
0x04
0x01
0x01
0x01
0x01
0xFF8000
0x4XX1
Data
SYNC
VD
HD
Reset all registers to default values
Standby3 vertical output polarities
Horizontal, vertical, shutter timing
Configure start-up register
Power-up the AFE, enables OB clamp
Starts CLO oscillator (if using crystal)
Starts internal timing core
Configure for master mode
Enable all outputs after SYNC
Configure sensor gate signals
SWSYNC (if using software SYNC)
Description
Figure 88. SYNC Timing to Synchronize the AD9927 with External Timing
SS
)
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SUSPEND
Power-Up and Synchronization in Slave Mode
The power-up procedure for slave mode operation is the same
as the procedure for master mode operation with two exceptions:
•
•
When the AD9927 is used in slave mode, the VD/HD inputs are
used to synchronize the internal counters. After a falling edge of
VD, there is a latency of 36 master clock CLI edges after the
falling edge of HD until the internal H-counter is reset. The
reset operation is shown in Figure 89.
Additional Restrictions in Slave Mode
When operating in slave mode, the following restrictions
should be noted:
•
•
Eliminate Step 8. Do not write the part into master mode.
No SYNC pulse is required in slave mode. Substitute
Step 10 with starting the external VD and HD signals.
This synchronizes the part, allows the register updates,
and starts the timing operation.
The HD falling edge should be located in the same CLI
clock cycle as the VD falling edge, or later than the VD
falling edge. The HD falling edge should not be located
within five cycles prior to the VD falling edge.
If possible, all start-up serial writes should be performed
with VD and HD disabled. This prevents unknown
behavior caused by partial updating of registers before all
information is loaded.