60 SBC329 3U VPX Single Board Computer
Publication No. SBC329-HRM/1
5.11 Serial Ports
The SBC329 provides a total of three serial COM ports, of which two (COM1 and
COM2) are available to the user. The third port is connected to the on-board IMPI
Board Management Microcontroller (BMM).
The COM ports each have a 16C550 UART compatible register set, and support is
available across a variety of Operating Systems.
COM1 supports only RS232, whereas COM2 supports RS232, RS422 and RS485.
The actual configuration of the serial ports depends on the variant of the board. The
following table summarizes the COM port connections:
Table 5-9 COM Port Connections
Port
Build Variant Availability
RS232 Signal Set
RS422/RS485 Signal Set
COM1
All variants
2-wire (TXD, RXD)
Not available
COM2
SBC329-xxxx1xxxx
2-wire (TXD, RXD)
Not available
SBC329-xxxx2xxxx
4-wire (TXD, RXD, RTS, CTS) 4-wire (TXD_A, TXD_B, RXD_A, RXD_B)
SBC329-xxxx3xxxx
Not available
Not available
COM3
Permanent connection to BMM -
-
The following table shows the COM1 and COM2 routing to the VPX backplane
connectors:
Table 5-10 COM1/COM2 Signal Availability
Port
RS232 Signal RS422/485 Signal Pin
COM1
COM1_RXD
-
P1/G11
COM1_TXD
-
P1/G9
COM2
COM2_RXD
COM2_RXD_A
P2/G5
COM2_TXD
COM2_TXD_A
P2/G3
COM2_CTS
COM2_RXD_B
P2/G9
COM2_RTS
COM2_TXD_B
P2/G7
COM1 and COM2 are connected using a single Intersil ISL 41334 transceiver, which
provides 15 kVolts ESD protection.
Figure 5-5 RS422/485 Signal Definition