AD9520-1SLASHPCBZ datasheet(55/80 Pages) AD

55 / 80 page

Data Sheet

AD9520-1

Rev. B | Page 55 of 80

The default mode of the AD9520-1 serial control port is the

bidirectional mode. In bidirectional mode, both the sent data

and the readback data appear on the SDIO pin. It is also possible to

set the AD9520-1 to unidirectional mode (Register 0x000[7] =

1b and Register 0x000[0] = 1b). In unidirectional mode, the

readback data appears on the SDO pin.

A readback request reads the data in the serial control port buffer

area or the data in the active registers (see Figure 63). Readback of

the buffer or active registers is controlled by Register 0x004[0].

The AD9520-1 uses Register 0x000 to Register 0xB03.

SERIAL

CONTROL

PORT

UPDATE

REGISTERS

WRITE REGISTER 0x232 = 0x001

TO UPDATE REGISTERS

SCLK/SCL

SDO

SDIO/SDA

Figure 63. Relationship Between Serial Control Port Buffer Registers and

Active Registers of the AD9520-1

SPI INSTRUCTION WORD (16 BITS)

The MSB of the instruction word is R/W, which indicates

whether the instruction is a read or a write. The next two bits

(W1:W0) indicate the length of the transfer in bytes. The final

13 bits are the address (A12:A0) at which to begin the read or

write operation.

For a write, the instruction word is followed by the number of

bytes of data indicated by Bits[W1:W0], see Table 44.

Table 44. Byte Transfer Count

Bytes to Transfer

Streaming mode

Bits[A12:A0] select the address within the register map that is

written to or read from during the data transfer portion of the

communications cycle. For multibyte transfers, this address is

the starting byte address. In MSB first mode, subsequent bytes

decrement the address.

SPI MSB/LSB FIRST TRANSFERS

The AD9520-1 instruction word and byte data can be MSB first

or LSB first. Any data written to Register 0x000 must be

mirrored; the upper four bits (Bits[7:4]) must mirror the lower

four bits (Bits[3:0]). This makes it irrelevant whether LSB first

or MSB first is in effect. As an example of this mirroring, see the

default setting for Register 0x000, which mirrors Bit 4 and Bit 3.

This sets the long instruction mode, which is the default and

the only mode that is supported.

The default for the AD9520-1 is MSB first.

When LSB first is set by Register 0x000[1] and Register

0x000[6], it takes effect immediately because it affects only the

operation of the serial control port and does not require that an

update be executed.

When MSB first mode is active, the instruction and data bytes

must be written from MSB to LSB. Multibyte data transfers in

MSB first format start with an instruction byte that includes the

data bytes must follow in order from the high address to the

low address. In MSB first mode, the serial control port internal

address generator decrements for each data byte of the multibyte

transfer cycle.

When LSB first is active, the instruction and data bytes must be

written from LSB to MSB. Multibyte data transfers in LSB first

format start with an instruction byte that includes the register

address of the least significant data byte followed by multiple

data bytes. In a multibyte transfer cycle, the internal byte

address generator of the serial port increments for each byte.

The AD9520-1 serial control port register address decrements

from the register address just written toward Register 0x000 for

multibyte I/O operations if the MSB first mode is active

(default). If the LSB first mode is active, the register address of

the serial control port increments from the address just written

toward Register 0x232 for multibyte I/O operations.

Streaming mode always terminates when it reaches Register

0x232. Note that unused addresses are not skipped during

multibyte I/O operations.

Table 45. Streaming Mode (No Addresses Are Skipped)

Write Mode

Address

Direction

Stop Sequence

LSB first

Increment

MSB first

Decrement

Table 46. Serial Control Port, 16-Bit Instruction Word, MSB First

MSB

LSB

I15

I14

I13

I12

I11

I10

R/W

A12 = 0

A11 = 0

A10 = 0

AD9520-1/PCBZ データシート(PDF) 55 Page - Analog Devices

AD9520-1/PCBZ データシート(HTML) 55 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

データシートダウンロード