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4–18
Up to 31 data bits plus a latch enable (SYNLE0,1,2) can be programmed in one programming cycle. When
data greater than or equal to 32 bits must be programmed, TI recommends using two or more programming
cycles with data in each cycle and a latch enable in the final programming cycle. Two or more programming
cycles are recommended because all programming cycles must contain at least one SYNCLK pulse,
whereas the latch enable can be suppressed in any programming cycle.
Figure 4–8 shows an example of the synthesizer output signals. In this case, an 18-bit pattern, 0x10664,
was chosen to write into synthesizer 1 with a positive-going latch enable pulse at the eighteenth bit. In order
to do so, the microcontroller writes the values 00h into SynData0, 00h into SynData1, 99h into SynData2,
41h into SynData3, 52h into SynCtrl0, 31h into SynCtrl1, and 32h into SynCtrl2.
10 6 6 4
SYNCLK
SYNDTA
SYNLE1
SYNLE0, 2
SYNRDY
Figure 4–8. Example Synthesizer Output
4.13 Power Control Port
For systems requiring minimum system current consumption, power can be provided to each functional part
of the TCM4300 only when that function is required for proper system operation. To accomplish this, the
TCM4300 provides six external power control signals accessible through the DStatCtrl and MStatCtrl
registers. These signals can be used to minimize the on time of the functional units. These power control
signals are SCEN, FMRXEN, IQRXEN, TXEN, PAEN, and OUT1 (see Table 4–15). The polarity of each of
these signals is high enable, low disable.
Table 4-15. External Power Control Signals
NAME SUGGESTED EXTERNAL APPLICATION
RESET
VALUE
SCEN Speech codec (microphone/speaker interface circuit) enable 0
FMRXEN FM demodulator enable 0
IQRXEN I and Q receive enable. IQRXEN enables the QPSK demodulator and the AGC amplifier 0
TXEN Transmit enable. TXEN enables power to the transmitter signal processing circuits: QPSK
modulator, voltage-controlled amplifier, driver amplifier, PA negative bias. This signal can
be used to enable these subsystems only during the transmit burst in digital mode.
0
OUT1 User defined 0
PAEN Power amplifier enable. PAEN enables power to PA. 0