Datasheet

DF1704
9
SBAS099A
RESET
SOFTWARE HARDWARE DEFAULT
FUNCTION (MODE = H) (MODE = L) (Software Mode)
Input Data Format Selection O O Standard Format
Input Word Length Selection O O 16 Bits
Output Word Length Selection O O 16 Bits
LRCIN Polarity Selection O O Left/Right = High/Low
Digital De-Emphasis O O OFF
Soft Mute O O OFF
Digital Attenuation O X 0dB, Independent L/R
Sample Rate for
De-Emphasis Function O O 44.1 kHz
Filter Roll-Off Selection O O Sharp Roll-Off Selected
CLKO Output Frequency Selection O O Same As XTI Input
Legend: O = User Programmable, X = Not Available.
TABLE III. User-Programmable Functions for Software and
Hardware Mode.
Programmable Functions
The DF1704 includes a number of programmable features,
with most being accessible from either Hardware or Soft-
ware mode. Table III summarizes the user programmable
functions for both modes of operation.
Hardware Mode Controls
With MODE = L, the DF1704 may be configured by
utilizing several user-programmable pins. The following is a
brief summary of the pin functions. Table IV provides more
details on setting the hardware mode controls.
Pins I
2
S, IW0, and IW1 are used to select the audio data
input format and word length.
Pins OW0 and OW1 are used to select the output data word
length.
The DEM pin is used to enable and disable the digital de-
emphasis function. De-emphasis is only available for 32kHz,
44.1kHz, and 48kHz sample rates.
Pins SF0 and SF1 are used to select the sample rate for the
de-emphasis function.
The SRO pin is used to select the digital filter response,
either sharp or slow roll-off.
The MUTE pin is used to enable or disable the soft mute
function.
The CKO pin is used to select the clock frequency seen at
the CLKO pin, either XTI or XTI ÷ 2.
The LRIP pin is used to select the polarity used for the audio
input left/right clock, LRCIN.
Finally, the RESV pin is not used by the current DF1704
design, but is reserved for future use.
Software Mode Controls
With MODE = H, the DF1704 may be configured by
programming four internal registers in software mode. ML
(pin 13), MC (pin 12), and MD (pin 11) make up the 3-wire
software control port, and may be controlled using DSP or
microcontroller general purpose I/O pins, or a serial port.
Table V provides an overview of the internal registers,
labeled MODE0 through MODE3.
t
BCKH
0.5V
DD
0.5V
DD
BCKO
DOL, R
t
BCKL
t
CKWK
t
WCKP
t
BCKP
t
CKDO
0.5V
DD
WCKO
BCKO Period
BCKO Pulse Width High
(4)
BCKO Pulse Width Low
(4)
Delay Time BCKO Falling Edge to WCKO Valid
WCKO Period
Delay Time BCKO Falling Edge to DOL, R Valid
Rising Time of All Signals
Falling Time of All Signals
t
BCKP
t
BCKH
t
BCKL
t
CKWK
t
WCKP
t
CKDO
t
R
t
F
min
typ
1/8 f
S
20ns
20ns
–5ns
–5ns
100ns
100ns
5ns
5ns
7ns
7ns
max
1/256 f
S
or 1/192 f
S
NOTES: (1) Timing measurement reference level is (V
IH
/V
IL
)/2. (2) Rising and falling time is
measured from 10% to 90% of IN/OUT signals’ swing. (3) Load capacitance of all signals
are 20pF. (4) Exceptions: f
S
= 96kHz and SCK = 256f
S
, t
BCKH
= 14ns (min)
t
BCKL
= 14ns (min)
FIGURE 7. Audio Output Data Format.