AD9920ABBCZ datasheet(94/112 Pages) AD

94 / 112 page

AD9920A

Rev. B | Page 94 of 112

LAYOUT OF INTERNAL REGISTERS

The AD9920A address space is divided into two register areas, as

illustrated in Figure 115. 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 0x400, consists of the V-pattern groups, V-sequences,

and field registers. This set of registers is configurable; 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 0x400. 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 0x400 plus

the number of V-pattern groups multiplied by 48. The starting

address for the fields is equal to the starting address of the

V-sequences plus the number of V-sequences multiplied by 40.

The V-pattern, V-sequence, and field registers must always

occupy a continuous block of addresses.

Figure 116 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 0x400. Because VPATNUM = 3,

the V-pattern groups occupy 144 address locations. The start of

the V-sequence registers is 0x490 (that is, 0x400 + 144). With

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

Therefore, the field registers begin at 0x530 (that is, 0x490 + 160).

The AD9920A address space contains many unused addresses.

Undefined addresses between Address 0x00 and Address 0xFF

should not be written to; otherwise, the AD9920A 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 0x400

FIELDS

MAX 0xFFF

VSEQ START

FIELD START

ADDR 0xFF

AFE REGISTERS

UPDATE CONTROL REGISTERS

MISCELLANEOUS REGISTERS

VD/HD REGISTERS

I/O, STBY POL REGISTERS

TIMING CORE REGISTERS

EXTRA REGISTERS

MEMORY, MODE REGISTERS

TEST REGISTERS

SHUTTER AND GPO REGISTERS

INVALID DO NOT ACCESS

Figure 115. Layout of AD9920A Registers

ADDR 0x400

ADDR 0x490

ADDR 0x530

ADDR 0x550

MAX 0xFFF

3 V-PATTERN GROUPS

(48 × 3 = 144 REGISTERS)

4 V-SEQUENCES

(40 × 4 = 160 REGISTERS)

2 FIELDS

(16 × 2 = 32 REGISTERS)

UNUSED MEMORY

Figure 116. Example Register Configuration

AD9920ABBCZ Datasheet(PDF) 94 Page - Analog Devices

AD9920ABBCZ Datasheet(HTML) 94 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL