Technical data

SYSTEM CONNECTOR INTERFACE

LZT 123 8020 R1A

5.15.3 UART3/IO#

The UART3 pins have been given alternative functions as

general purpose I/O, both pins may be used for either input or

output. However, the TX pin has a 100kΩ pull-down resistor to

ground and the RX pin has a 100kΩ pull-up resistor to 2.75V.

This must be taken into consideration when designing the host

circuit.

5.15.4 IO#/ADC#

To increase analog input capabilities, the radio device optimises

the I/O by multiplexing or sharing different features on single

pins. There are two digital I/O pins which now have an

additional ADC input. When configured as digital I/O, the

software will not read the voltages at the two new ADC inputs.

When configured as ADC inputs the software will configure the

digital I/O pins as input or high impedance tri-state. In this state

any applied voltage between 0V and 2.75V can be read as an 8

bit value.

Because the additional ADC inputs (ADC4 and ADC5) are

common with digital I/O, the input circuit of the ADC is not the

same as for the original circuits ADC1-3. It is important to

understand the input structure of the pin so that the correct

analog voltage is read by the application.

5.16 General Purpose Analogue I/O Ports

Pin Signal Dir Description

20 DAC O Digital to analogue conversion output

26 ADC1 I Analogue to digital conversion input 1

27 ADC2 I Analogue to digital conversion input 2

28 ADC3 I Analogue to digital conversion input 3

13 ADC4 (I/O5) I (I/O) Analogue to digital conversion input 4

22 ADC5 (I/O2) I (I/O) Analogue to digital conversion input 5

The radio device is able to convert digital to analogue signals

and vice versa.

5.16.1 Digital to Analogue Converter - DAC

The DAC is an 8-bit converter. Conversion takes place when an

AT command is sent to the radio device. The radio device

sends the resulting analogue value to the DAC pin.

Tolerance on this internal voltage is ±5%.