User's Manual

FLC-BTM501 Datasheet
Flaircomm Microelectronics Confidential
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The gain of the output stage is controlled by a 3-bit programmable resistive divider, which sets the
gain in steps of approximately 3dB.
The multi-bit stream from the digital circuitry is low pass filtered by a second order bi-quad filter
with a pole at 20kHz. The signal is then amplified in the fully differential output stage, which has a
gain bandwidth of typically 1MHz.
4.4 RF Interface
The module integrates a balun filter. The user can connect a 50ohms antenna directly to the RF port.
4.5 General Purpose Analog IO
The general purpose analog IOs can be configured as ADC inputs by software. Do not connect them
if not use.
4.6 General Purpose Digital IO
There are nine general purpose digital IOs defined in the module. All these GPIOs can be configured
by software to realize various functions, such as button controls, LED displays or interrupt signals to
host controller, etc. Do not connect them if not use.
4.6.1 Audio Signal Control
PIOs can be used to switch on/off external audio amplifier and microphone-bias generation. Please
contact with Flaircomm for the special firmware.
FLC-BTM501
PIO5
PIO11
External Audio
Amplifier
Mic Bias Generation
Figure 4: An Example of the Audio Signal Control by PIOs