User's Guide

ME910C1 HW User Guide
1VV0301351 Rev. 2 Page 49 of 81 2017-07-19
on the level translator. Note that the negative signal voltage must be less than 0V and
hence some sort of level translation is always required.
The simplest way to translate the levels and invert the signal is by using a single chip level
translator. There are a multitude of them, differing in the number of drivers and receivers
and in the levels (be sure to get a true RS232 level translator not a RS485 or other
standards).
By convention the driver is the level translator from the 0-1.8V UART to the RS232 level.
The receiver is the translator from the RS232 level to 0-1.8V UART.
In order to translate the whole set of control lines of the UART you will need:
• 5 drivers
• 3 receivers
An example of RS232 level
adaptation circuitry could be done
using a MAXIM transceiver
(MAX218)
In this case the chipset is capable
to translate directly from 1.8V to
the RS232 levels (Example done
on 4 signals only).
The RS232 serial port lines are usually connected to a DB9 connector with the following
layout:
General purpose I/O
The ME910C1 module is provided by a set of Configurable Digital Input / Output pins
(CMOS 1.8V). Input pads can only be read; they report the digital value (high or low)