SI4707-B20 Datasheet, PDF (18/30 Pages) Silicon Laboratories – WEATHER BAND AND SAME DATA RECEIVER

Si4707-B20
 0xA0 = read a response (device drives one
additional byte on GPO1).
 0xE0 = read a response (device drives 16 additional
bytes on GPO1).
For write operations, the system controller must drive
exactly eight data bytes (a command and seven
arguments) on SDIO after the control byte. The data is
captured by the device on the rising edge of SCLK.
For read operations, the controller must read exactly
one byte (STATUS) after the control byte or exactly 16
data bytes (STATUS and RESP1–RESP15) after the
control byte. The device changes the state of SDIO (or
GPO1, if specified) on the falling edge of SCLK. Data
must be captured by the system controller on the rising
edge of SCLK.
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.
4.9. GPO Outputs
The Si4707 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.
4.10. Firmware Upgrades
The Si4707 contains on-chip program RAM to
accommodate minor changes to the firmware. This
allows Silicon Laboratories to provide future firmware
updates to optimize the characteristics of new radio
designs and those already deployed in the field.
4.11. 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.
4.12. Programming with Commands
To ease development time and offer maximum
customization, the Si4707 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 complete list of
commands is available in Table 11, “Si4707 Command
Summary,” on page 19.
Properties are a special command argument used to
modify the default chip operation and are generally
configured immediately after powerup. A complete list of
properties is available in Table 12, “Si4707 Property
Summary,” on page 20.
Responses provide the user information and are
echoed after a command and associated arguments are
issued. All commands provide a one-byte status update,
which indicates interrupt and clear-to-send status
information. For a detailed description of the commands
and properties for the Si4707, see “AN332:
Si47xxProgramming Guide.”
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Rev. 0.8