SI4731-B-EVB Silicon Laboratories Inc, SI4731-B-EVB Datasheet - Page 18

• Manufacturer Part Number: SI4731-B-EVB
• Description: DEVELOPMENT KIT SI4731
• Manufacturer: Silicon Laboratories Inc
• Type: Receiverr

Specifications of SI4731-B-EVB

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Si4730, Si4731
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: Q3885405

Si4730/31-A10
4.8. Soft Mute
The soft mute feature is available to attenuate the audio
outputs and minimize audible noise in very weak signal
conditions. The softmute attenuation level is adjustable
using the FM_SOFT_MUTE_MAX_ATTENUATION and
AM_SOFT_MUTE_MAX_ATTENUATION properties.
4.9. RDS/RBDS Processor (Si4731 Only)
The Si4731 implements an RDS/RBDS* processor for
symbol
detection, and error correction.
The Si4731 device is user configurable and provides an
optional interrupt when RDS is synchronized, loses
synchronization, and/or the user configurable RDS
FIFO threshold has been met.
The Si4731 reports RDS decoder synchronization
status, and detailed bit errors in the information word for
each RDS block with the FM_RDS_STATUS command.
The range of reportable block errors is 0, 1–2, 3–5, or
6+.
corresponding block information word contains six or
more
checkword contains errors.
*Note: RDS/RBDS is referred to only as RDS throughout the
4.10. Tuning
The frequency synthesizer uses Silicon Laboratories’
proven technology, including a completely integrated
VCO.
quadrature local oscillator signal used to downconvert
the RF input to a low intermediate frequency. The VCO
frequency is locked to the reference clock and adjusted
with an automatic frequency control (AFC) servo loop
during reception. The tuning frequency can be directly
programmed
AM_TUNE_FREQ commands. The Si4730/31 supports
channel spacing of 50, 100, or 200 kHz in FM mode and
9 or 10 kHz in AM mode.
4.11. Seek
Seek tuning will search up or down for a valid channel.
Valid channels are found when the receive signal
strength indicator (RSSI) and the signal-to-noise ratio
(SNR) values exceed the set threshold. Using the SNR
qualifier rather than solely relying on the more
traditional RSSI qualifier can reduce false stops and
increase the number of valid stations detected. Seek is
initiated
AM_SEEK_START commands. The RSSI and SNR
threshold settings are adjustable using properties (see
Table 13).
18
More
remainder of this document.
non-correctable
The
decoding,
using
than
frequency
using
six
the
block
the
errors,
errors
synthesizer
FM_SEEK_START
FM_TUNE_FREQ
synchronization,
or
indicates
that
generates
the
that
block
error
and
and
the
the
Rev. 1.0
Two seek options are available. The device will either
wrap or stop at the band limits. If the seek operation is
unable to find a channel, the device will indicate failure
and return to the channel selected before the seek
operation began.
4.12. Reference Clock
The Si4730/31 reference clock is programmable,
supporting RCLK frequencies in Table 10. Refer to
Table 3, “DC Characteristics,” on page 5 for switching
voltage
Characteristics” on page 11 for frequency tolerance
information.
An onboard crystal oscillator is available to generate the
32.768 kHz reference when an external crystal and load
capacitors are provided. Refer to "2. Typical Application
Schematic" on page 14. This mode is enabled using the
POWER_UP
Command Summary,” on page 21.
The Si4730/31 performance may be affected by data
activity on the SDIO bus when using the integrated
internal oscillator. SDIO activity results from polling the
tuner for status or communicating with other devices
that share the SDIO bus. If there is SDIO bus activity
while the Si4730/31 is performing the seek/tune
function, the crystal oscillator may experience jitter,
which may result in mistunes, false stops, and/or lower
SNR.
For
recommends that all SDIO data traffic be suspended
during Si4730/31 seek and tune operations. This is
achieved by keeping the bus quiet for all other devices
on the bus, and delaying tuner polling until the tune or
seek operation is complete. The STC (seek/tune
complete) interrupt should be used instead of polling to
determine when a seek/tune operation is complete.
4.13. Control Interface
A serial port slave interface is provided, which allows an
external controller to send commands to the Si4730/31,
and receive responses from the device. The serial port
can operate in three bus modes: 2-wire mode, 3-wire
mode, or SPI mode. The Si4730/31 selects the bus
mode by sampling the state of the GPO1 and GPO2
pins on the rising edge of RST. The GPO1 pin includes
an internal pull-up resistor which is connected while
RST is low, and the GPO2 pin includes an internal pull-
down resistor which is connected while RST is low.
Therefore, it is only necessary for the user to actively
drive pins which differ from these states. See Table 11.
best
levels
seek/tune
command,
and
results, Silicon
Table 8,
see
Table 12,
“FM
Laboratories
Receiver
“Si473x