AN332
Confidential Rev. 0.2
63
Command 0x20. FM_TUNE_FREQ
Sets the FM Receive to tune a frequency between 64 and 108 MHz in 10 kHz units. The CTS bit (and optional
interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid
argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC
interrupt is set when the command completes. The STCINT bit is set only after the GET_INT_STATUS command is
called. This command may only be sent when in powerup mode. The command clears the STC bit if it is already
set. See Figure 17, “CTS and STC Timing Model,” on page 187 and Table 42, “Command Timing Parameters for
the FM Receiver,” on page 188.
Note:
For FMRX components less than 2.0, tuning range is 76–108 MHz.
Command arguments: Four
Response bytes: None
Command
Response
Bit
D7
D6
D5
D4
D3
D2
D1
D0
CMD
0
0
1
0
0
0
0
0
ARG1
0
0
0
0
0
0
0
0
ARG2
FREQ
H
[7:0]
ARG3
FREQ
L
[7:0]
ARG4
ANTCAP[7:0]
ARG
Bit
Name
Function
1
7:0
Reserved
Always write to 0.
2
7:0
FREQ
H
[7:0]
Tune Frequency High Byte.
This byte in combination with FREQ
L
selects the tune frequency in 10 kHz. In
FM mode the valid range is from 6400 to 10800 (64–108 MHz).
3
7:0
FREQ
L
[7:0]
Tune Frequency Low Byte.
This byte in combination with FREQ
H
selects the tune frequency in 10 kHz. In
FM mode the valid range is from 6400 to 10800 (64–108 MHz).
4
7:0
ANTCAP[7:0]
Antenna Tuning Capacitor (valid only when using TXO/LPI pin as the
antenna input).
This selects the value of the antenna tuning capacitor manually, or automati-
cally if set to zero. The valid range is 0 to 191.
Bit
D7
D6
D5
D4
D3
D2
D1
D0
STATUS
CTS
ERR
X
X
RSQINT
RDSINT
X
STCINT
