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AN332
112
Confidential Rev. 0.2
Command 0x40. AM
_
TUNE
_
FREQ
Tunes the AM/SW/LW receive to a frequency between 149 and 23 MHz in 1 kHz steps. In AM only mode, the valid
frequency is between 520 and 1710 kHz in 1 kHz steps. 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 43, “Command Timing Parameters for the AM Receiver,” on page 189.
Command arguments: Four
Response bytes: None
Command
Bit
D7
D6
D5
D4
D3
D2
D1
D0
CMD
0
1
0
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
H
[15:8]
ARG5
ANTCAP
L
[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 kHz. In
AM/SW/LW mode, the valid range is from 149 to 23000 (149 kHz–23 MHz).
In AM only mode the valid range is from 520 to 1710 (520–1710 kHz).
3
7:0
FREQ
L
[7:0]
Tune Frequency Low Byte.
This byte in combination with FREQ
H
selects the tune frequency in kHz. In
AM/SW/LW mode, the valid range is from 149 to 23000 (149 kHz–23 MHz).
In AM only mode the valid range is from 520 to 1710 (520–1710 kHz).
4
15:8
ANTCAP
H
[15:8]
Antenna Tuning Capacitor High Byte.
This byte in combination with ANTCAP
L
selects the tuning capacitor value. If
both bytes are set to zero, the tuning capacitor value is selected automati-
cally. If the value is set to anything other than 0, the tuning capacitance is
manually set as 95 fF x 7 pF. ANTCAP manual range is
1–6143.
5
7:0
ANTCAP
L
[7:0]
Antenna Tuning Capacitor Low Byte.
This byte in combination with ANTCAP
H
selects the tuning capacitor value. If
both bytes are set to zero, the tuning capacitor value is selected automati-
cally. If the value is set to anything other than 0, the tuning capacitance is
manually set as 95 fF x 7 pF. ANTCAP manual range is
1–6143.
Содержание Si4700
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