Datasheet

AD9979
Rev. C | Page 29 of 56
Single-Field Toggles
Single-field toggles begin in the field following the register write.
There can be up to two toggles in the field. The mode is set with
GPx_PROTOCOL equal to 1. In this mode, the field toggle
settings must be set to 1. Toggles repeat for each field until
GPx_PROTOCOL is set to 0. GPx_PROTOCOL must be reset
to 0 for one field before it can be active again.
Preparation
The GP toggle positions can be programmed any time prior to
use. For example,
0x054 ← 0x000A001
0x055 ← 0x0002000
0x056 ← 0x000000F
Details
A) Field 0: 0x052 ← 0x0000001
B) Field 1: 0x052 ← 0x0000000
VD
1
REG WRITE
AB
G
P1_PROTOCOL 0 1 0
GPO1
NOTES
1. THE FIELD TOGGLE POSITION IS IGNORED WHEN THE GPO
PROTOCOL IS 1.
TOGGLE POSITIONS REPEAT FOR EACH FIELD UNTIL
GPO PROTOCOL IS RESET.
2
05957-038
Figure 36. Single-Field Toggles Using GP1_PROTOCOL = 1
Scheduled Toggles
Scheduled toggles are programmed to occur during any upcoming
field. For example, there can be one toggle in Field 1 and the next
toggle in Field 3. The mode is set with GPx_PROTOCOL = 2,
which tells the GPO to obey the primary field counter.
Preparation
The GP toggle positions can be programmed any time prior to
use. For example,
0x054 ← 0x00C4002
0x055 ← 0x0004000
0x056 ← 0x00000B3
Details
A) Field 0: 0x050 ← 0x0000001
0x052 ← 0x0000002
VD 1 2
REG WRITE
A
GP1_PROTOCOL
0
PRIMARY
COUNT
0120
GPO1
THE PRIMARY COUNTER REGULATES THE SUBCK
AND VSG ACTIVITY. LINK A GPO TO THE PRIMARY COUNTER
ONLY IF IT IS TO HAPPEN DURING EXPOSURE/READ.
(IDLE)
2
05957-039
Figure 37. Scheduled Toggles Using GP1_PROTOCOL = 2
RapidShot Sequences
RapidShot technology provides continuous repetition of scheduled
toggles. As in the case of scheduled toggles, a pulse can traverse
multiple fields. The mode is set with GPx_PROTOCOL = 3,
which tells the GPO to obey the repeating primary field counter.
GPx_PROTOCOL must be reset to 0 for one field before it can
be active again.
Preparation
The GPO toggle positions can be programmed any time prior
to use. For example,
0x051 ← 0x0000002
0x054 ← 0x000A001
0x055 ← 0x0004000
0x056 ← 0x000000F
0x052 ← 0x0000003
Details
A) Field 0: 0x050 ← 0x0000002
B) Field 2: 0x050 ← 0x0000007
VD
12345
REG WRITE
AB
GP1_PROTOCOL
03
0 (IDLE)121210
GPO1
TERMINATED
AT VD EDGE
NOTES
1. THE GPO PROTOCOLS ARE THE SAME AS THE SCHEDULED
TOGGLES, EXCEPT THE TOGGLES CAN BE EXCLUDED FROM
REPETITION BY CHOOSING GPO PROTOCOL 2.
CAUTION! THE FIELD COUNTER MUST BE FORCED INTO IDLE
STATE TO TERMINATE REPETITIONS.
PRIMARY
COUNT
05957-040
Figure 38. RapidShot Toggle Operation Using GP1_PROTOCOL = 3