Intel 8XC251SB, 8XC251SA, 8XC251SP, 8XC251SQ specifications 8xC251TB, 8xC251TQ Hardware Description

8xC251Tx Hardware Description

8xC251TB, 8xC251TQ Hardware Description

Addendum to the 8xC251SA, 8xC251SB, 8xC251SP, 8xC251SQ, User’s Manual

1.0	INTRODUCTION TO THE 8xC251Tx
1.1	Comparing the 8xC251Tx and 8xC251Sx	1
2.0	SIGNAL SUMMARY
3.0	THE SECOND SERIAL I/O PORT
3.1	Overview	7
3.2	Special Function Register Definitions	9

3.2.1	SCON1	9
3.2.2	SBUF1	10
3.2.3	SADDR1	10
3.2.4	SADEN1	10
3.2.5	BGCON	10
3.2.6	IE1	11
3.2.7	IPH1	11
3.2.8	IPL1	11
4.0 EXTENDED DATA FLOAT TIMING
4.1	Summary of the Extended Data Float Timing Changes	12
FIGURES
Figure 1	8xC251Tx Block Diagram	1
TABLES
Table 1.	8xC251Tx Signal Summary	2
Table 2.	8xC251Tx Signal Descriptions	3
Table 3.	Special Function Register (SFR) Map	6
Table 4.	Second Serial I/O Port Signals	7
Table 5.	Second Serial I/O Port Special Function Registers	8
Table 6.	SCON1 Special Function Register Definitions	9
Table 7.	BGCON Special Function Register Definitions	10
Table 8.	IE1 Special Function Register Definitions	11
Table 9.	IPH1 Special Function Register Definitions	11
Table 10.	IPL1 Special Function Register Definitions	11
Table 11.	Interrupt Priority of Second Serial I/O Port	11
Table 12.	UCONFIG1 bit definitions for the 8xC251Tx	12
Table 13.	Summary of the EDF# and WSB#[1:0] Configuration Options	13

273138-002 December 2003 v