Table 12-14. Serial Port Control Register Ports A and B

 

Serial Port x Control Register

(SACR)

(Address = 0xC4)

 

 

 

 

(SBCR)

(Address = 0xD4)

 

 

 

 

 

 

Bit(s)

 

Value

 

Description

 

 

 

 

 

7:6

 

00

No operation. These bits are ignored in the Async mode.

 

 

 

 

 

 

 

01

In clocked serial mode, start a byte receive operation.

 

 

 

 

 

 

 

 

10

In clocked serial mode, start a byte transmit operation.

 

 

 

 

 

 

 

11

In clocked serial mode, start a byte transmit operation and a byte receive

 

 

operation simultaneously.

 

 

 

 

 

 

 

 

 

 

 

 

 

5:4

 

00

Parallel Port C is used for input.

 

 

 

 

 

 

 

 

 

 

01

Parallel Port D is used for input.

 

 

 

 

 

 

 

 

 

 

1x

Disable the receiver input.

 

 

 

 

 

 

 

3:2

 

00

Async mode with 8 bits per character.

 

 

 

 

 

 

 

01

Async mode with 7 bits per character. In this mode the most significant bit of a

 

 

byte is ignored for transmit, and is always zero in receive data.

 

 

 

 

 

 

 

 

 

 

 

Clocked serial mode with external clock.

 

 

 

10

Serial Port A clock is on Parallel Port PB1

 

 

 

 

Serial Port B clock is on Parallel Port PB0

 

 

 

 

 

 

 

 

 

Clocked serial mode with internal clock.

 

 

 

11

Serial Port A clock is on Parallel Port PB1

 

 

 

 

Serial Port B clock is on Parallel Port PB0

 

 

 

 

 

 

1:0

 

00

The Serial Port interrupt is disabled.

 

 

 

 

 

 

 

 

01

The Serial Port uses Interrupt Priority 1.

 

 

 

 

 

 

 

 

10

The Serial Port uses Interrupt Priority 2.

 

 

 

 

 

 

 

User’s Manual

173

Page 182
Image 182
Jameco Electronics 3000, 2000 manual Serial Port Control Register Ports a and B, Sacr, Sbcr