Table 12-8. Data Register All Ports

 

Serial Port x Data Register

(SADR)

(Address = 0xC0)

 

 

 

 

(SBDR)

(Address = 0xD0)

 

 

 

 

(SCDR)

(Address = 0xE0)

 

 

 

 

(SDDR)

(Address = 0xF0)

 

 

 

 

(SEDR)

(Address = 0xC8)

 

 

 

 

(SFDR)

(Address = 0xD8)

Bit(s)

 

Value

 

Description

 

 

 

 

 

 

7:0

 

Read

Returns the contents of the receive buffer.

 

 

 

 

 

 

 

Write

Loads the transmit buffer with a data byte for transmission.

 

 

 

 

 

 

 

 

Table 12-9. Address Register All Ports

Serial Port x Address Register

(SAAR)

(Address = 0xC1)

 

 

 

(SBAR)

(Address = 0xD1)

 

 

 

(SCAR)

(Address = 0xE1)

 

 

 

(SDAR)

(Address = 0xF1)

 

 

 

(SEAR)

(Address = 0xC9)

 

 

 

(SFAR)

(Address = 0xD9)

Bit(s)

Value

 

Description

 

 

 

 

 

 

Returns the contents of the receive buffer. In Clocked Serial mode reading the

 

Read

data from this register automatically causes the receiver to start a byte receive

 

operation (the current contents of the receive buffer are read first), eliminating

 

 

 

 

the need for software to issue the Start Receive command.

 

 

 

7:0

 

Loads the transmit buffer with an address byte, marked with a “zero” address bit,

 

 

for transmission. In HDLC mode, the last byte of a frame must be written to this

 

Write

register to enable subsequent CRC and closing Flag transmission. In Clocked

 

Serial mode writing the data to this register causes the transmitter to start a byte

 

 

 

 

transmit operation, eliminating the need for the software to issue the Start

 

 

Transmit command.

 

 

 

 

 

 

 

168

Rabbit 3000 Microprocessor

Page 177
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Jameco Electronics 2000, 3000 manual Data Register All Ports, Address Register All Ports