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Flow description:
<81E97>: Enable the DAC1, AMP1, MIC, PGA circuits. Setup the circuit switch first.
DAC1, AMP1 on-enable the MOD output. MIC on–enable the microphone circuit. PGA
on–enable the PGA input source.
<81B10>: Select the PGA, audio input source locations. Select the PGA input source to
be MIC and the audio out to be DAC common-mode bias to reduce noise.
<81140> Enter the Tx mode. Select the Tx mode as the final step to enter the Tx
processing flow.
Rx Mode
This mode is mainly used for baseband signal demodulation. Although it is acceptable to
wait for the RF signal in this mode, it is recommended that the MCU verifies the RSSI
(Receive signal strength indicator) signal before switching the input source to the
DEMOD path and then enabling the audio processor for management. In this way, power
can be saved and in the meantime prevented from erroneous signal judgments. The
mode switches, path select, circuit ON/OFF and the SPI command settings are as
follows:
Ex: RX mode, Input = DEMOD, Output = AUDO(sources = DAC1), No sub-tones.
Rx mode Setup Flow
Flow description:
<RSSI OK>: Confirm if the RF signal is OK.
<81E8B>: Enable the DAC1, Buffer and PGA circuits. Setup the circuit switches first.
DAC1 on - enable the DAC1 output. AUDO output buffer on–enable the audio output
circuit. PGA on–enable the PGA input source.
<81B25>: Select the PGA, audio input source path. Select the PGA input source to be
DEMOD, audio out sources to be DAC1 and then switch the DAC1 pin source path to
the internal common -mode bias to prevent audio signal leakage from MOD.
<81160> Enter the Rx mode. Select the Rx mode as the final step to enter the Rx
processing flow.
HT98R068 Two-way Radio MCU
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