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AD9948

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POWER-UP PROCEDURE

VDD

(INPUT)

SERIAL

WRITES

(OUTPUT)

1 H

ODD FIELD

EVEN FIELD

...

DIGITAL

OUTPUTS

CLOCKS ACTIVE WHEN OUT_CONTROL REGISTER IS

UPDATED AT VD/HD EDGE

H1/H3, RG

H2/H4

tPWR

CLI

(INPUT)

(OUTPUT)

...

Figure 14. Recommended Power-Up Sequence

Recommended Power-Up Sequence

When the AD9948 is powered up, the following sequence is

recommended (refer to Figure 14 for each step):

1. Turn on the power supplies for the AD9948.

2. Apply the master clock input, CLI, VD, and HD.

3. Although the AD9948 contains an on-chip power-on reset, a

software reset of the internal registers is recommended. Write

a 1 to the SW_RST register (Address x010), which will reset

all the internal registers to their default values. This bit is

self-clearing and will automatically be reset back to 0.

4. The Precision Timing core must be reset by writing a 0 to the

TGCORE_RSTB register (Address x012) followed by writing

a l to the TGCORE_RSTB register. This will start the internal

timing core operation.

5. Write a 1 to the PREVENTUPDATE register (Address x014).

This will prevent the updating of the serial register data.

6. Write to the desired registers to configure high speed timing

and horizontal timing.

7. Write a 1 to the OUT_CONTROL register (Address x011).

This will allow the outputs to become active after the next

VD/HD rising edge.

8. Write a 0 to the PREVENTUPDATE register (Address x014).

This will allow the serial information to be updated at next

VD/HD falling edge.

The next VD/HD falling edge allows register updates to occur,

including OUT_CONTROL, which enables all clock outputs.

AD9948 Datasheet(PDF) 19 Page - Analog Devices

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