Hardware Manual

WARNING:

Consider a mechanical design and a low-capacitance ESD protection device to protect HE910

V2 or customer specific requirements from ESD event to UART port (M15, N15, P15 and

L14).

Serial port 2 on the HE910 V2 is a +1.8V UART with only the RX and TX signals.

The signals of the HE910 V2 serial port are:

PAD

Signal

I/O

Function

Type

D15

TX_AUX

Auxillary UART (TX Data to DTE)

1.8V

E15

RX_AUX

Auxillary UART (RX Data from DTE)

1.8V

NOTE:

In order to avoid a back powering effect it is recommended to avoid having any HIGH logic

level signal applied to the digital pins of the HE910 V2 when the module is powered off or

during an ON/OFF transition.

In order to interface the Telit HE910 V2 with a PC com port or a RS232 (EIA/TIA-232)

application, a level translator is required. This level translator must:

 Invert the electrical signal in both directions

 Change the level from 0/1.8V to +/-15V

Actually, the RS232 UART 16450, 16550, 16650 & 16750 chipsets accept signals with lower

levels on the RS232 side (EIA/TIA-562), allowing a lower voltage-multiplying ratio on the