Fm Radio Interface - LG KP110 Service Manual

3.12 FM RADIO INTERFACE

The Si4702 patented digital low-IF architecture reduces external components and eliminates the need
for factory adjustments. The receive (RX) section integrates a low noise amplifier (LNA) supporting the
worldwide FM broadcast band (76 to 108MHz). An automatic gain control (AGC) circuit controls the
gain of the LNA to optimize sensitivity and rejection of strong interferers.
For two-wire operation, a transfer begins with the START condition. The control word is latched
internally on rising SCLK edges and is eight bits in length,comprised of a seven bit device address
equal to 0010000b and a read/write bit (write = 0 and read = 1).
The device acknowledges the address by setting SDIO low on the next falling SCLKedge. For write
operations, the device acknowledge Is followed by an eight bit data word latched internally on rising
edges of SCLK. The device always acknowledges the data by setting SDIO low on the next falling
SCLK edge.
An internal address counter automatically increments to allow continuous data byte writes, starting
with the upper byte of register 02h, followed by the lower byte of register 02h, and onward until the
lower byte of the last register is reached. The internal address counter then automatically wraps
around to the upper byte of register 00h and proceeds from there until continuous writes cease. Data
transfer ceases with the STOP command. After every STOP Command, The internal address counter
is reset.
For read operations, the device acknowledge is followed by an eight bit data word shifted out on falling
SCLK edges. An internal address counter automatically increments to allow continuous data byte
reads, starting with the upper byte of register 0Ah, followed by the lower byte of register 0Ah, and
onward until the lower byte of the last register is reached.
The internal address counter then automatically wraps around to the upper byte of register 00h and
proceeds from there until continuous reads cease.
After each byte of data is read, the controller IC should return an acknowledge if an additional byte of
data will be requested. Datatransfer ceases with the STOP command. After every STOP command,
the internal address counter is reset.
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3. TECHNICAL BRIEF
- 33 -
LGE Internal Use Only