AD9927BBCZ datasheet(83/100 Pages) AD

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AD9927

Rev. 0 | Page 83 of 100

LAYOUT OF INTERNAL REGISTERS

The AD9927 address space is divided into two register areas, as

illustrated in Figure 99. In the first address space, Address 0x00

to Address 0xFF contain the registers for the AFE, miscellaneous,

VD/HD, I/O and CP, timing core, shutter and GPO, and update

control functions. The second address space, beginning at

Address 0x800, consists of the V-pattern groups, V-sequences,

and field registers. This is a configurable set of registers; the

user can decide how many V-pattern groups, V-sequences, and

fields are used in a particular design. Therefore, the addresses

for these registers vary, depending on the number of V-patterns

and V-sequences chosen.

Address 0x28 specifies the total number of V-pattern groups

and V-sequences used. The starting address for the V-pattern

groups is always 0x800. The starting address for the

V-sequences is based on the number of V-pattern groups used,

with each V-pattern group occupying 48 register addresses. The

starting address for the field registers depends on both the

number of V-pattern groups and the number of V-sequences.

Each V-sequence occupies 40 register addresses, and each field

occupies 16 register addresses.

The starting address for the V-sequences is equal to 0x800 plus

the number of V-pattern groups times 48. The starting address

for the fields is equal to the starting address of the V-sequences

plus the number of V-sequences times 40. The V-pattern,

V-sequence, and field registers must always occupy a

continuous block of addresses.

Figure 100 shows an example in which three V-pattern groups,

four V-sequences, and two fields are used. The starting address

for the V-pattern groups is always 0x800. Since VPATNUM = 3,

the V-pattern groups occupies 144 address locations. The start

of the V-sequence registers is 0x890 (that is, 0x800 + 144). With

VSEQNUM = 4, the V-sequences occupy 160 address locations.

Therefore, the field registers begin at 0x930 (that is, 0x890 + 160).

The AD9927 address space contains many unused addresses.

Undefined addresses between Address 0x00 and Address 0xFF

should not be written to; otherwise, the AD9927 may operate

incorrectly. Continuous register writes should be performed

carefully so that undefined registers are not written to.

FIXED REGISTER AREA

ADDR 0x00

V-PATTERN GROUPS

V-SEQUENCES

CONFIGURABLE REGISTER AREA

VPAT START 0x800

FIELDS

MAX 0xFFF

VSEQ START

FIELD START

ADDR 0xFF

AFE REGISTERS

UPDATE CONTROL REGISTERS

MISCELLANEOUS REGISTERS

VD/HD REGISTERS

I/O AND CP REGISTERS

TEST REGISTERS

TIMING CORE REGISTERS

MODE REGISTERS

TEST REGISTERS

SHUTTER AND GPO REGISTERS

INVALID DO NOT ACCESS

Figure 99. Layout of AD9927 Registers

ADDR 0x800

ADDR 0x890

ADDR 0x930

ADDR 0x950

MAX 0xFFF

3 V-PATTERN GROUPS

(48× 3= 144REGISTERS)

4 V-SEQUENCES

(40× 4= 160REGISTERS)

2FIELDS

(16× 2= 32 REGISTERS)

UNUSED MEMORY

Figure 100. Example Register Configuration

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