
VIPER Technical Manual
Detailed hardware description
© 2007 Eurotech Ltd Issue E
64
Serial COMs ports
There are five high-speed, fully functionally compatible 16550 serial UARTs on the
VIPER. Four of these channels can be used as standard RS232 serial interfaces, and
the remaining one (COM5) can be configured as RS422 or RS485.
Port Address
IRQ
FIFO depth
RX / TX
Signals
COM1 0x40100000 –
0x40100023
Internal
64 / 64
RS232 Rx, Tx, CTS, RTS, RI, DSR,
DCD, DTR
COM2 0x40200000 –
0x40200023
Internal
64 / 64
RS232 Rx, Tx, RTS, CTS
COM3 0x40700000 –
0x40700023
Internal
64 / 64
RS232 Rx, Tx
COM4 0x14300010 –
0x1430001F
GPIO4
128 / 128 RS232 Rx, Tx, CTS, RTS, RI, DSR,
DCD, DTR
COM5 0x14300000 –
0x1430000F
GPIO3
128 / 128 RS422 / RS485 Tx, Rx
Please see the PXA255 Developer’s Manual for details of internal interrupts.
COM1 – RS232 interface
Uses the full function UART in the PXA255 (FFUART). The port is buffered to RS232
levels with ±15kV ESD protection, and supports full handshaking and modem control
signals. The maximum baud rate on this channel is 230.4kb/s (CPU max capability). A
factory fit option configures COM1 as TTL Level signals to interface to a modem.
Please contact Eurotech Ltd for details. Contact details are provided in
COM2 – RS232 interface
Uses the Bluetooth UART in the PXA255 (BTUART). The port is buffered to RS232
levels with ±15kV ESD protection, and supports full handshaking and modem control
signals. The maximum baud rate on this channel is 921.6kb/s (CPU max capability).
COM3 – RS232 interface
Uses the Standard UART in the PXA255 (STUART). The port is buffered to RS232
levels with ±15kV ESD protection, and supports full handshaking and modem control
signals. The maximum baud rate on this channel is 230.4kb/s (CPU max capability).
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