Jameco Electronics Rabbit 3000 - Manual (Page 170)

User’s Manual 161
12. R
ABBIT
S
ERIAL
P
ORTS
The Rabbit 3000 has 6 on-chip serial ports designated A, B, C, D, E, and F. All the ports can per-
form asynchronous serial communications at high baud rates. Ports A-D can operate as clocked
ports. Ports A and B can be switched to alternate pins. Ports E and F support SDLC/HDLC syn-
chronous communications in addition to standard asynchronous communications. Port A has the
special capability of being used to remote boot the microprocessor via asynchronous, synchro-
nous, or IrDA (asynchronous serial).
Table 12-1 lists the synchronous serial port signals.
Table 12-1. Serial Port Signals
Serial Port Signal Name Function
Serial Port A TXA Serial Transmit Out
RXA Serial Transmit In
CLKA Clock for clocked mode (bidirectional)
ATXA Alternate serial transmit out
ARXA Alternate serial receive in
Serial Port B TXB Serial Transmit Out
RXB Serial Transmit In
CLKB Clock for clocked mode (bidirectional)
ATXB Alternate serial transmit out
ARXB Alternate serial receive in
Serial Port C TXC Serial Transmit Out
RXC Serial Transmit In
CLKC Clock for clocked mode (bidirectional)
Serial Port D TXD Serial Transmit Out
RXD Serial Transmit In
CLKD Clock for clocked mode (bidirectional)
Serial Port E TXE Serial Transmit Out
RXE Serial Transmit In
TCLKE Optional external transmit clock
RCLKE Optional external receive clock