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Programmable Hardware Manual (PHM)
© Tibbo Technology Inc.
The EM1206 module features an
and a dedicated VCCB input for providing
backup power when the EM1206EV is off. On the EM1206EV, the backup power
comes from a supercapacitor located on the bottom side of the board. The
supercapacitor charges almost instantly and, in the absence of main power,
supports the RTC for about a week.
Notice that the supercapacitor is not connected to the Vcc line directly. The
VCCB pin "expects" the backup power to have a nominal voltage of 2.5V. See
the
topic of the EM1206 manual for details.
Multi-channel RS232 Port and Expansion Connector
The
module has four serial ports (four pairs of RX and TX lines). Each of
those lines can also be used as general-purpose I/O. Hence, each line can serve as
a CTS, RTS, DSR, or DTR line; or play another role which is unrelated to the function
of the serial port.
The I/O lines of the EM1206 module are bi-directional: each line can be programmed
to work as an output or input line. On the RS232 port of the EM1206EV, however,
each line has a fixed direction defined by the RS232 transceiver IC. The IC used on
the EM1206EV board implements three outputs and four inputs. Therefore, only
seven I/O lines of the EM1206 are connected to the RS232 port of the EM1206EV
board.