12.RABBIT SERIAL PORTS

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 12-1lists 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

 

 

 

User’s Manual

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Jameco Electronics 3000, 2000 manual Rabbit Serial Ports, Serial Port Signals, Serial Port Signal Name Function