CS5530 datasheet(31/36 Pages) CIRRUS

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CS5530

DS742F2

2.11 Getting Started

This A/D converter has several features. From a

software programmer’s prospective, what should

be done first? To begin, a 4.9152 MHz or 4.096

MHz crystal takes approximately 20 ms to start. To

accommodate for this, it is recommended that a

software delay of approximately 20 ms be inserted

before the start of the processor’s ADC initializa-

tion code. Next, since the CS5530 does not provide

a power-on-reset function, the user must first ini-

tialize the ADC to a known state. This is accom-

plished by resetting the ADC’s serial port with the

Serial Port Initialization sequence. This sequence

resets the serial port to the command mode and is

accomplished by transmitting 15 SYNC1 com-

mand bytes (0xFF hexadecimal), followed by one

SYNC0 command (0xFE hexadecimal). Once the

serial port of the ADC is in the command mode, the

user must reset all the internal logic by performing

a system reset sequence (see 2.3.2 System Reset

Sequence). After the converter is properly reset,

the configuration register bits should be configured

as appropriate, for example, the voltage reference

selection, word rate, signal polarity(unipolar or bi-

polar) should be configured.

Calibrations or conversions can then be performed

as appropriate.

2.12 PCB Layout

For optimal performance, the CS5530 should be

placed entirely over an analog ground plane. All

grounded pins on the ADC, including the DGND

pin, should be connected to the analog ground

plane that runs beneath the chip. In a split-plane

system, place the analog-digital plane split imme-

diately adjacent to the digital portion of the chip.

CS5530 데이터시트(PDF) 31 Page - Cirrus Logic