Intel 8XC196K Series User Manual page 595

Table of Contents

8XC196K x, J x , CA USER'S MANUAL

The serial port baud rate (SP_BAUD) register selects the serial port baud rate and clock source. The

most-significant bit selects the clock source. The lower 15 bits represent BAUD_VALUE, an unsigned

integer that determines the baud rate.

The maximum BAUD_VALUE is 32,767 (7FFFH). In asynchronous modes 1, 2, and 3, the minimum

BAUD_VALUE is 0000H when using XTAL1 and 0001H when using T1CLK. In synchronous mode 0, the

minimum BAUD_VALUE is 0001H for transmissions and 0002H for receptions.

On the 87C196CA, 8XC196J x devices the T1CLK pin is not implemented; therefore, on these devices

this bit is reserved and should be written as one.

Serial Port Clock Source

This bit determines whether the serial port is clocked from an internal or

an external source.

1 = XTAL1 (internal source)

0 = T1CLK (external source)

These bits constitute the BAUD_VALUE.

Use the following equations to determine the BAUD_VALUE for a given

Synchronous mode 0:

------------------------------------- - 1

Asynchronous modes 1, 2, and 3:

---------------------------------------- - 1

For mode 0 receptions, the BAUD_VALUE must be 0002H or greater.

Otherwise, the resulting data in the receive shift register will be incorrect.

Reset State:

--------------------------- -

------------------------------------- -