si4704 Silicon Laboratories, si4704 Datasheet - Page 24

• Manufacturer Part Number: si4704
• Description: Broadcast Fm Radio Receiver For Consumer Electronics
• Manufacturer: Silicon Laboratories

Si4704/05-C40
Keep SEN low until all bytes have transferred. A
transaction may be aborted at any time by setting SEN
high and toggling SCLK high and then low. Commands
will be ignored by the device if the transaction is
aborted.
For details on timing specifications and diagrams, refer
to Figure 6 and Figure 7 on page 10.
4.14. GPO Outputs
The Si4704/05 provides three general-purpose output
pins. The GPO pins can be configured to output a
constant low, constant high, or high-impedance. The
GPO pins can be reconfigured as specialized functions.
GPO2/INT can be configured to provide interrupts and
GPO3 can be configured to provide external crystal
support or as DCLK in digital audio output mode.
4.15. Reset, Powerup, and Powerdown
Setting the RST pin low will disable analog and digital
circuitry, reset the registers to their default settings, and
disable the bus. Setting the RST pin high will bring the
device out of reset.
A powerdown mode is available to reduce power
consumption when the part is idle. Putting the device in
powerdown mode will disable analog and digital circuitry
while keeping the bus active.
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Rev. 1.0
4.16. Programming with Commands
To ease development time and offer maximum
customization, the Si4704/05 provides a simple yet
powerful software interface to program the receiver. The
device is programmed using commands, arguments,
properties, and responses.
To perform an action, the user writes a command byte
and associated arguments, causing the chip to execute
the given command. Commands control an action such
as powerup the device, shut down the device, or tune to
a station. Arguments are specific to a given command
and are used to modify the command. A partial list of
commands is available in Table 13, “Selected Si4704/05
Commands,” on page 25.
Properties are a special command argument used to
modify the default chip operation and are generally
configured immediately after powerup. Examples of
properties are de-emphasis level, RSSI seek threshold,
and soft mute attenuation threshold. A partial list of
properties is available in Table 14, “Selected Si4704/05
Properties,” on page 26.
Responses provide the user information and are
echoed after a command and associated arguments are
issued. All commands provide a one-byte status update
indicating interrupt and clear-to-send status information.
For a detailed description of the commands and
properties for the Si4704/05, see “AN332: Universal
Programming Guide.”