273138-002 December 2003 v

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 Funct ion Register Defini tions.... ...................... .................... ...................... ........ 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 ...................... ............. ............ .......... ............ ............ .......... ............ ............ .... 1 1
3.2.8 IPL1 ...................... ........................... ......................... .......................... ................... 1 1
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 R egister (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 Fun ction Register Def initions. ................... ...................... ........... 9
Table 7. BGCON Special Function Re g is te r D e fin it i o ns ..... .. .. .................... .. ... ................ 10
Table 8. IE1 Special Function Regist e r D ef in it ions..... ... ................... ... .. .................... .. .. .. 11
Table 9. IPH1 Special Function Regi st e r D ef in it io n s ...................... .. .................... .. ... ...... 11
Table 10. IPL1 Special Function Reg i st er Definitions ............... ... ................... ... .. .............. 11
Table 11. Interrupt Priority of Sec o nd S er ia l I/ O Port......... ... .. .. .................... .. ... ................ 11
Table 12. UCONFIG1 bit definitions for the 8xC251Tx........... ...................... ................... .. 12
Table 13. Summary of the EDF# and WSB#[1:0 ] Configuration Op tions............. .............. 13