Egnite Ethernut 5.0, Hardware Manual, Page: 15 / 40

Board Overview
RS-232 Interface
Ethernut provides an on-board DB-9 male connector for RS-232 serial
communication, wired as a DTE (data terminal equipment) port. IC6 is used to
convert the required voltage levels for RS-232 from the 3.3V power supply.
Use a null-modem cable to connect a PC to this port. A suitable cable will have
female 9-pin D-Sub connectors on both ends. The following table shows the cable
wiring:
Connector A Pin Connector B Pin
1+6 4
2 3
3 2
4 1+6
5 5
7 8
8 7
By default 8 data bits, no parity, 1 stop bit and 115,200 baud without handshake
will be used. The boot loader firmware supplied with the Ethernut board assumes
this configuration.
Any of the following serial interfaces of the microcontroller can be tied to the RS-
232 connector via JP1 jumper settings: DBGU, USART0 or USART2. In the default
configuration the debug interface (DBGU) is attached to the connector.
Note, that USART0 handshake line may conflict with any hardware (image sensor)
attached to the FFC connector J4.
DB-9 connector attached to DGBU. Default.
DB-9 connector attached to USART0.
DB-9 connector attached to USART0 with hardware
handshake.
DB-9 connector attached to USART0 with full modem
handshake.
DB-9 connector attached to USART2.
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