Interfaces and Connectors
Bengal (VL-EPMe-30) Reference Manual
27
RS-485 Mode Line Driver Control
The transmit line driver can be automatically turned on and off based on data availability in the
UART output FIFO. This mode can be enabled in the BIOS Setup utility. The transmit line driver
can be enabled in the BIOS Setup utility.
Serial Port Connectors
The pinouts of the DB9M connectors apply to the serial connectors on the VL-CBR-5015
paddleboard.
These connectors use IEC 61000-4-2-rated TVS components to help protect against ESD
damage.
Table 13: COM1-2 Pinout
– VL-CBR-5015 Connector J3
COM1
COM2
RS-232
RS-422
RS-485
Top DB9
J3 Pin
Bottom DB9
J3 Pin
1
1
—
—
—
2
2
RXD*
RxD-
RxD-
3
3
TXD*
TxD-
TxD-
4
4
—
—
—
5
5
Ground
Ground
Ground
6
6
—
—
—
7
7
RTS
TxD+
TxD+
8
8
CTS
RxD+
RxD+
9
9
—
—
—
I
2
C
Pins 14 and 15 of I/O connector J18 connect to the first of the seven I
2
C ports on the Intel Atom
“Bay Trail” processor. The Bengal has a 3.3 V I
2
C interface. The required pullups for this interface
are included in the Bengal design. The 3.3 V power for this interface is the same as used for the
digital I/O interface. By default, this power is turned off when the processor is in a sleep state.
GPIO
I/O connector J18 provides two general-purpose I/O signals:
GPIO1 on pin 20
GPIO2 on pin 18
These signals connect to the FPGA on the Bengal.
