53
Programmable Hardware Manual (PHM)
© Tibbo Technology Inc.
Many I/O lines of the EM1206 have alternative functions and serve as inputs or
outputs of special function modules: On the EM1206, the special function modules
are four
and the
. When any special function
module is enabled, its I/O lines seize to work as inputs/outputs and are controlled by
this special function module directly. Depending on the nature of an alternative
function a given I/O line is to perform, your application may still have to manually
configure this line for input or output. The table below details which special function
module lines require manual configuration:
RX lines of serial ports
Automatically configured as inputs when a
corresponding serial port is enabled, revert to
previous state when this port is disabled.
TX lines of serial ports
Automatically configured as outputs when a
corresponding serial port is enabled, revert to
previous state when this port is disabled.
CTS lines of serial ports
Must be configured as inputs by your application.
Note that CTS lines can be "remapped".
RTS lines of serial ports
Must be configured as outputs by your application.
Note that RTS lines can be "remapped".
CO (square wave output)
Automatically configured as output when the square
wave is being generated, reverts to previous state
when the square wave output stops.
4.3.1.2
Ethernet Port Lines
Ethernet port of the EM1206 is of 100BaseT type. Onboard electronics of the
EM1206 do not include Ethernet magnetics, so magnetic circuitry must be
connected externally to pins TX+, TX-, RX+, RX-, and AVCC. The AVCC pin outputs
clean 1.8V power for the magnetics circuitry, which is very sensitive to noise.
Separate AGND analog ground is also provided. Please, note the following:
·
The AVCC is an output!
·
Do not combine AVCC with the VCC (main power) pin. This will apply wrong
voltage to the AVCC pin. Doing so appears to cause no immediate permanent
damage to the EM1206, but the circuit will not work and the effects of prolonged
over-voltage on the AVCC line are not known.