AD9958SLASHPCB datasheet(31/40 Pages) AD

31 / 40 page

AD9958

Rev. 0 | Page 31 of 40

SERIAL I/O MODES OF OPERATION

The following are the four programmable modes of the serial

I/O port operation:

Single bit serial 2-wire mode (default mode).

Single bit serial 3-wire mode.

2-bit serial mode.

4-bit serial mode (SYNC_I/O not available).

Table 6 displays the function of all six serial I/O interface pins,

depending on the mode of serial I/O operation programmed.

Table 26. Serial I/O Port Pin Function vs. Serial I/O Mode

Name

Single Bit

Serial 2-Wire

Mode

Single Bit

Serial 3-Wire

Mode

2-Bit

Serial

Mode

4-Bit

Serial

Mode

SCLK

Serial

Clock

CSB

Chip Select

Chip

Select

Chip

Select

SDIO_0

Serial Data

I/O

Serial Data In

Serial

Data I/O

Serial

Data

I/O

SDIO_1

Not used for

SDIO1

Not used for

SDIO1

Serial

Data I/O

Serial

Data

I/O

SDIO_2

Not used for

SDIO1

Serial Data

Out (SDO)

Not used

for SDIO1

Serial

Data

I/O

SDIO_3

SYNC_I/O

Serial

Data

I/O

1In serial mode, these pins can be used for RU/RD operation

The two bits CSR <2:1> in the channel select register set the

serial I/O mode of operation are defined as follows:

CSR <2:1> = 00. Single bit serial mode (2-wire mode).

CSR <2:1> = 01. Single bit serial mode (3-wire mode).

CSR <2:1> = 10. 2-bit serial mode.

CSR <2:1> = 11. 4-bit serial mode.

Single Bit Serial (2- and 3-Wire) Modes

The single bit serial mode interface allows read/write access to

all registers that configure the AD9958. MSB-first or LSB-first

transfer formats are supported. In addition, the single bit serial

mode interface port can be configured as either a single pin I/O,

which allows a two-wire interface or two unidirectional pins for

in/out, which enable a 3-wire interface. Single bit mode allows

the use of the SYNC_I/O function.

In single-bit serial mode, 2-wire interface operation, the

SDIO_0 pin is the single serial data I/O pin. In single-bit serial

mode 3-wire interface operation, the SDIO_0 pin is the serial

data input pin and the SDIO_2 pin is the output data pin.

Regardless of the number of wires used in the interface, the

SDIO_3 pin is configured as an input and operates as the

SYNC_I/O pin in the single-bit serial mode and 2-bit serial

mode. The SDIO_1 pin is unused in this mode. See Table 26.

2-Bit Serial Mode

The SPI port operation in 2-bit serial mode is identical to the

SPI port operation in single bit serial mode, except that two bits

of data are registered on each rising edge of SCLK. Therefore, it

only takes four clock cycles to transfer eight bits of information.

The SDIO_0 pin contains the even numbered data bits using

the notation D <7:0> and the SDIO_1 pin contains the odd

numbered data bits. This even and odd numbered pin/data

alignment is valid in both MSB- and LSB-first formats (see

Figure 39).

4-Bit Serial Mode

The SPI port in 4-bit serial mode is identical to the SPI port in

single bit serial mode, except that four bits of data are registered

on each rising edge of SCLK. Therefore, it only takes two clock

cycles to transfer eight bits of information. The SDIO_0 and

SDIO_2 pins contain even numbered data bits using the

notation D <7:0> and the SDIO_0 pin contains the LSB of the

nibble. The SDIO_1 and SDIO_3 pins contain the odd

numbered data bits and the SDIO_1 pin contains the LSB of the

nibble to be accessed.

Note that when programming the device for 4-bit serial mode,

it is important to keep the SDIO_3 pin at Logic 0 until the

device is programmed out of the single bit serial mode. Failure

to do so can result in the serial I/O port controller being out of

sequence.

Figure 42 through Figure 44 represent write timing diagrams

for each serial I/O modes available. Both MSB and LSB-first

modes are shown. LSB-first bits are shown in parenthesis. The

clock stall low/high feature shown is not required. It is used to

show that data (SDIO) must have the proper setup time relative

to the rising edge of SCLK.

AD9958/PCB датащи(PDF) 31 Page - Analog Devices

AD9958/PCB датащи(HTML) 31 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

датащи скачать

ссылки URL