8251 - USART

Block Diagram

Mode Word Format

S2 S1 EP PEN L2 L1 B2 B1

B2, B1   specifies Baud Rate Factor

B2	B1	Baud Rate Factor
0	0	For synchronous Mode
0	1	1 x
1	0	16 x
1	1	64 x

L2, L1 specifies Length of the characters in Data

L2	L1	Length of characters
0	0	5 Bits
0	1	6 Bits
1	0	7 Bits
1	1	8 Bits