AX5243 datasheet(41/65 Pages) ONSEMI

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Circuit Description

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AX5243

5.17. General Purpose ADC (GPADC)

The AX5243 features a general purpose ADC. The ADC input pins are GPADC1 and

GPADC2. The ADC converts the voltage difference between applied between pins

GPADC1 and GPADC2. If pin GPADC2 is left open, the ADC converts the difference

between an internally generated value of 800 mV and the voltage applied at pin

GPADC1.

The GPADC can only be used if the receiver is disabled. To enable the GPADC write 1 to

the GPADC13 bit in the

GPADCCTRL register. To start a single conversion, write 1 to the

BUSY bit in the

GPADCCTRL register. Then wait for the BUSY bit to clear, or the GPADC

Interrupt to be asserted. The GPADC Interrupt is cleared by reading the result register

GPADC13VALUE.

If continuous sampling is desired, set the CONT bit in register

GPADCCTRL. The desired

sampling rate can be specified in the

GPADCPERIOD register.

5.18.  DAC

One digital pin – TCXO_EN – may be used as a  Digital-to-Analog Converter. A simple

RC lowpass filter is needed to smooth the output. The DAC may be used to output RSSI,

many demodulator variables, or a constant value under software control.

AX5243 Datasheet(PDF) 41 Page - ON Semiconductor