CS5529 datasheet(21/31 Pages) CIRRUS

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CS5529

DS246F5

Performing Conversions

The CS5529 offers two modes of performing con-

versions: single conversion and continuous conver-

sions.

The

sections

that

detail

the

differences and provides examples illustrating how

to use the modes. Note that it is assumed that the

configuration register has been initialized before

conversions are performed.

Performing Conversions with PF bit = 0

A single conversion is performed after the user

transmits the single conversion command (0xC0

Hexadecimal). At the completion of the conver-

sion, the DF (Done Flag) bit of the configuration

sion is being performed, the user can read the con-

figuration register to determine if the DF bit is set.

Once DF has been set, the read conversion data reg-

ister command (0x96 Hexadecimal) can be issued

to read the conversion data register to obtain the

conversion data word.

Note:

1)The DF bit of the configuration register will

be cleared to logic 0 when the conversion

data register, the gain register, or the offset

configuration register will not clear the DF flag

bit.

2) If another single conversion command is

issued to the converter while it is performing

a conversion, the filter will abandon the

current conversion and restart a new

convolution cycle.

Performing Conversions with PF bit = 1

The PF (Port Flag) bit in the configuration register

eliminates the need for the user to monitor the DF

(Done Flag) in the configuration register to deter-

mine if the conversion is available. When PF is set

to a logic 1, SDO’s output pin behaves as a flag sig-

nal indicating when conversions are completed.

SDO will fall to logic 0 once a new conversion is

complete.

Single Conversion

A single conversion is performed after the user

transmits the single conversion command (0xC0

Hexadecimal). At the completion of the conver-

sion, SDO will fall to logic 0 to indicate that the

conversion is complete. To acquire the conversion,

the user must issue 8 SCLKs with SDI = logic 0

(i.e. the NULL command) to clear the SDO flag.

Upon the falling edge of the 8th SCLK, the SDO

pin will present the first bit (MSB) of the conver-

sion word. 24 SCLKs (high, then low) are then re-

quired to read the conversion word from the port.

Note:

1) The user must not give an explicit

command (other than the NULL command) to

read the conversion data register when the

PF bit is set to logic 1.

2) The data conversion word must be read

before a new command can be entered as the

converter will remain in the data mode until

the conversion word is read.

3) Once the conversion is read the converter

returns to the command mode.

Continuous Conversions

Continuous conversions are performed after the

user transmits the continuous conversions com-

mand (0xA0 Hexadecimal). At the completion of a

conversion, SDO will fall to logic 0 to indicate that

the conversion is complete. To read the conversion

word, the user must issue 8 SCLKs with SDI = log-

ic 0 (i.e. the NULL command) to clear the SDO

flag. Upon the falling edge of the 8th SCLK, the

SDO pin will present the first bit (MSB) of the con-

version word. 24 SCLKs (high, then low) are then

required to read the conversion word from the port.

When operating in the continuous conversion

mode, the user need not read every conversion. If

the user chooses not to read a conversion after SDO

falls, SDO will rise one XIN clock cycle before the

next conversion word is available and then fall

again to signal that another conversion word is

available. To exit the continuous conversion mode,

the user must issue any valid command, other than

the NULL command, to the SDI input when the

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