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Embedded Modules
© Tibbo Technology Inc.
lines are configured as inputs). You need to explicitly enable the output buffer of a
certain I/O line if you want this line to become an output.
Many I/O lines of the EM1202 also serve as inputs or outputs of special function
modules, such as serial ports. Majority of those lines need to be correctly configured
as inputs or outputs -- this won't happen automatically. Several lines -- such as TX
and RX lines of the serial port when in the UART mode -- are configured as outputs
and inputs automatically when the serial port (or some other hardware block) is
enabled. For details see Platform-dependent Programming Information inside the
EM1202 platform documentation (TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual).
Each I/O line has a weak pull-up resistor that prevents the line from floating when
the output buffer is tri-stated.
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I/O line control is described in detail in the documentation for the I/O (io.) object
found inside the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual.
4.6.1.2
Ethernet Port Lines
Ethernet port of the EM1202 is of 100BaseT type. Onboard electronics of the
EM1202 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 2.5V 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 be causing no immediate permanent
damage to the EM1202, but the circuit will not work and the effects of prolonged
over-voltage on the AVCC line are not known.
You can use either a standalone magnetics part (such as YCL-PH163112) or RJ45
connector with integrated magnetics (i.e. YCL-PTC1111-01G). Here is a connection
diagram for the YCL-PTC1111-01G jack with integrated magnetics.