SN8F2270B Series
USB 2.0 Low-Speed 8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD Page 4 Version1.3
3.1 OVERVIEW........................................................................................................................................... 38
3.2 POWER ON RESET............................................................................................................................... 40
3.3 WATCHDOG RESET............................................................................................................................ 40
3.4 BROWN OUT RESET ........................................................................................................................... 41
3.4.1 BROWN OUT DESCRIPTION........................................................................................................ 41
3.4.2 THE SYSTEM OPERATING VOLTAGE DECSRIPTION............................................................... 42
3.4.3 BROWN OUT RESET IMPROVEMENT......................................................................................... 43
3.5 EXTERNAL RESET .............................................................................................................................. 44
3.6 EXTERNAL RESET CIRCUIT ............................................................................................................. 44
3.6.1 Simply RC Reset Circuit.................................................................................................................. 44
3.6.2 Diode & RC Reset Circuit............................................................................................................... 45
3.6.3 Zener Diode Reset Circuit............................................................................................................... 45
3.6.4 Voltage Bias Reset Circuit............................................................................................................... 46
3.6.5 External Reset IC............................................................................................................................. 46
4SYSTEM CLOCK.................................................................................................................................. 47
4.1 OVERVIEW........................................................................................................................................... 47
4.2 CLOCK BLOCK DIAGRAM................................................................................................................. 47
4.3 OSCM REGISTER................................................................................................................................. 48
4.4 SYSTEM HIGH CLOCK ....................................................................................................................... 49
4.4.1 INTERNAL HIGH RC...................................................................................................................... 49
4.5 SYSTEM LOW CLOCK ........................................................................................................................ 49
4.5.1 SYSTEM CLOCK MEASUREMENT............................................................................................... 50
5SYSTEM OPERATION MODE........................................................................................................... 51
5.1 OVERVIEW........................................................................................................................................... 51
5.2 SYSTEM MODE SWITCHING EXAMPLE......................................................................................... 52
5.3 WAKEUP ............................................................................................................................................... 54
5.3.1 OVERVIEW ..................................................................................................................................... 54
5.3.2 WAKEUP TIME............................................................................................................................... 54
6INTERRUPT........................................................................................................................................... 55
6.1 OVERVIEW........................................................................................................................................... 55
6.2 INTEN INTERRUPT ENABLE REGISTER......................................................................................... 56
6.3 INTRQ INTERRUPT REQUEST REGISTER....................................................................................... 56
6.4 GIE GLOBAL INTERRUPT OPERATION .......................................................................................... 57
6.5 PUSH, POP ROUTINE........................................................................................................................... 57
6.6 INT0 (P0.0) &INT1 (P0.1) INTERRUPT OPERATION....................................................................... 59
6.7 T0 INTERRUPT OPERATION.............................................................................................................. 61
6.8 TC0 INTERRUPT OPERATION........................................................................................................... 62
6.9 USB INTERRUPT OPERATION .......................................................................................................... 63
