I/O Pin Assignment and Pin Functions
The EM203A has two connectors -- main connector and magnetics connector. Depending on the EM203A version , magnetics connector can be soldered facing up or down, as described in the Mechanical Dimensions topic.
Main connector
#1 |
MD* |
Input |
Mode selection pin |
#2 |
RST |
Input |
Reset, active high |
#3 |
P3 DTR* |
Input/output Output |
General-purpose input/output line Data terminal ready output |
#4 |
P2 DSR* |
Input/output Input |
General-purpose input/output line Data set ready input |
#5** |
L3 SG* |
Output Output |
LED output 3 Green status LED control line |
#6** |
L4 SR* |
Output Output |
LED output 4 Red status LED control line |
#7** |
VCC |
|
Positive power input, 5V nominal, +/- 5%, app. 220mA |
#8** |
GND |
|
Ground |
#9 |
RX |
Input |
Serial receive line |
#10 |
TX |
Output |
Serial transmit line |
#11 |
P4 CTS/SEL* |
Input/output Input |
General-purpose input/output line Clear to send input; full-/half-duplex selection input |
#12 |
P5 RTS/DIR* |
Input/output Output |
General-purpose input/output line Request to send output (full-duplex mode); data direction control output (half-duplex mode) |
* Implemented in (supported through) firmware.
** For the EM203A device (without "D" option), these pins also extend upward so that they can potentially mate with the RJ203A module.
Magnetics connector
#1 |
RX+ |
Input |
Ethernet port, positive line of the differential input signal pair |
#2 |
RX- |
Input |
Ethernet port, negative line of the differential input signal pair |
#3 |
AVCC |
Output |
"Clean" 3.3V power output for magnetics circuitry |
#4 |
TX+ |
Output |
Ethernet port, positive line of the differential output signal pair |
#5 |
TX- |
Output |
Ethernet port, negative line of the differential output signal pair |
#6 |
L1(EG) |
Output |
Green Ethernet status LED control line. |
#7 |
L2(EY) |
Output |
Yellow Ethernet status LED control line. |