HT98R068-1 Two-way Radio OTP MCU
TX Mode
Entering the TX mode depens on the input data trigger, such as pressing PTT, audio
signal (VOX)…etc.The mode switches, input source selection, circuit disabling etc will be
generally executed in this mode. As for the audio buffer input source, it is recommended
to switch to bias voltage to reduce noise, or disable the buffer (I/O CMD-1Eh [3]), or even
choose both. During TX/RX switching, it is recommended to execute circuit ON/OFF
path select
mode switch so as to decrease the generation of error signals. The
following illustrates the PTT processing:
Ex: Setup the TX mode, Input = MIC, Output = MOD, No Sub-tone.
Tx Mode Setup Flow
Flow description:
<81E97>: Enable the DDAC1, AMP1, MIC and 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 input PGA and audio input source paths. Select the PGA input
source to be MIC and the audio output to be DAC common-mode bias voltage to
reduce noise.
<81140>: Enter the TX mode. Select the TX mode as the final step to enter the TX
processing flow.
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