SN8F2250B Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
3.6.2 Diode & RC Reset Circuit............................................................................................... 44
3.6.3 Zener Diode Reset Circuit .............................................................................................. 44
3.6.4 Voltage Bias Reset Circuit.............................................................................................. 45
3.6.5 External Reset IC ........................................................................................................... 45
4
SYSTEM CLOCK.................................................................................................................... 46
4.1 OVERVIEW........................................................................................................................... 46
4.2 CLOCK BLOCK DIAGRAM ................................................................................................... 46
4.3 OSCM REGISTER ................................................................................................................ 47
4.4 SYSTEM HIGH CLOCK......................................................................................................... 48
4.4.1 EXTERNAL HIGH CLOCK ............................................................................................. 48
4.4.1.1 CRYSTAL/CERAMIC............................................................................................... 49
4.1.1.2 EXTERNAL CLOCK SIGNAL................................................................................... 50
4.2 SYSTEM LOW CLOCK ......................................................................................................... 51
4.2.1 SYSTEM CLOCK MEASUREMENT............................................................................... 51
5
6
SYSTEM OPERATION MODE................................................................................................ 52
5.1 OVERVIEW........................................................................................................................... 52
5.2 SYSTEM MODE SWITCHING EXAMPLE............................................................................. 53
5.3 WAKEUP............................................................................................................................... 55
5.3.1 OVERVIEW.................................................................................................................... 55
5.3.2 WAKEUP TIME .............................................................................................................. 55
INTERRUPT............................................................................................................................ 56
6.1 OVERVIEW........................................................................................................................... 56
6.2 INTEN INTERRUPT ENABLE REGISTER ............................................................................ 57
6.3 INTRQ INTERRUPT REQUEST REGISTER......................................................................... 58
6.4 GIE GLOBAL INTERRUPT OPERATION.............................................................................. 59
6.5 PUSH, POP ROUTINE.......................................................................................................... 59
6.6 INT0 (P0.0) & INT1 (P0.1) INTERRUPT OPERATION........................................................... 60
6.7 T0 INTERRUPT OPERATION............................................................................................... 62
6.8 T1 INTERRUPT OPERATION............................................................................................... 63
6.9 TC0 INTERRUPT OPERATION ............................................................................................ 64
6.10 TC1 INTERRUPT OPERATION .......................................................................................... 65
6.11 USB INTERRUPT OPERATION.......................................................................................... 66
6.12 WAKEUP INTERRUPT OPERATION.................................................................................. 67
6.13 SIO INTERRUPT OPERATION........................................................................................... 68
6.14 MULTI-INTERRUPT OPERATION...................................................................................... 69
7
8
I/O PORT................................................................................................................................. 70
7.1 I/O PORT MODE................................................................................................................... 70
7.2 I/O PULL UP REGISTER....................................................................................................... 71
7.3 I/O PORT DATA REGISTER ................................................................................................. 72
7.4 I/O PORT1 WAKEUP CONTROL REGISTER....................................................................... 73
TIMERS................................................................................................................................... 74
8.1 WATCHDOG TIMER............................................................................................................. 74
8.2 TIMER 0 (T0)......................................................................................................................... 76
8.2.1 OVERVIEW.................................................................................................................... 76
8.2.2 T0M MODE REGISTER ................................................................................................. 76
8.2.3 T0C COUNTING REGISTER ......................................................................................... 77
8.2.4 T0 TIMER OPERATION SEQUENCE............................................................................ 78
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