VULCAN Technical Manual
Detailed hardware description
© 2007 Eurotech Ltd Issue D
32
Serial COMs ports
There are four high speed fully functionally compatible 16550 serial UARTs on the
VULCAN. Three of these channels can be used as standard RS232 serial interfaces,
and the remaining one can be configured as either RS422 or RS485.
Port Controller
IRQ FIFO
depth
RX / TX
Signals
COM1 IXP425
‘High-speed’
UART
Internal
64 / 64
RS232 Rx,Tx,RTS, CTS
COM2 IXP425
‘Console’
UART
Internal
64 / 64
RS232 Rx,Tx,RTS, CTS
COM3
XR162551L DUART
GPIO4
16 / 16
RS232 Rx, Tx, CTS, RTS,
RI, DSR, DCD, DTR
COM4
XR162551L DUART
GPIO4
16 / 16
RS422/RS485 Tx, Rx
The terms ‘High-speed’ and ‘Console’ UART are used in Intel IXP425 technical
documentation only to make a distinction between the two UART interfaces.
Both UART Interfaces exhibit exactly the same features. The term ‘Console’
doesn’t presume the use of this UART by user’s software.
Further details about each of these COMs ports is provided below:
COM1 – RS232 interface
Uses the ‘High-speed’ UART in the IXP425, with 64 bytes-deep transmit and receive
buffers. The port is buffered to RS232 levels by a 3V transceiver with ±15kV ESD
protection, and supports RTS, CTS handshaking signals only. The maximum baud rate
on this channel is 921.6KBaud.
COM2 – RS232 interface
Uses the ‘Console’ UART in the IXP425, with 64 bytes-deep transmit and receive
buffers. The port is buffered to RS232 levels by a 3V transceiver with ±15kV ESD
protection, and supports RTS, CTS handshaking signals only. The maximum baud rate
on this channel is 921.6KBaud/s.