NH82801GBM SL8YB

Manufacturer Part NumberNH82801GBM SL8YB
ManufacturerIntel Corporation
NH82801GBM SL8YB datasheet
 


Specifications of NH82801GBM SL8YB

CaseBGADate_code07+
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
Page 141
142
Page 142
143
Page 143
144
Page 144
145
Page 145
146
Page 146
147
Page 147
148
Page 148
149
Page 149
150
Page 150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
Page 146/848

Download datasheet (7Mb)Embed
PrevNext
5.12
Real Time Clock (D31:F0)
The Real Time Clock (RTC) module provides a battery backed-up date and time keeping
device with two banks of static RAM with 128 bytes each, although the first bank has
114 bytes for general purpose usage. Three interrupt features are available: time of
day alarm with once a second to once a month range, periodic rates of 122 µs to
500 ms, and end of update cycle notification. Seconds, minutes, hours, days, day of
week, month, and year are counted. Daylight savings compensation is available. The
hour is represented in twelve or twenty-four hour format, and data can be represented
in BCD or binary format. The design is functionally compatible with the Motorola
MS146818B. The time keeping comes from a 32.768 kHz oscillating source, which is
divided to achieve an update every second. The lower 14 bytes on the lower RAM block
has very specific functions. The first ten are for time and date information. The next
four (0Ah to 0Dh) are registers, which configure and report RTC functions.
The time and calendar data should match the data mode (BCD or binary) and hour
mode (12 or 24 hour) as selected in register B. It is up to the programmer to make
sure that data stored in these locations is within the reasonable values ranges and
represents a possible date and time. The exception to these ranges is to store a value
of C0–FFh in the Alarm bytes to indicate a don’t care situation. All Alarm conditions
must match to trigger an Alarm Flag, which could trigger an Alarm Interrupt if enabled.
The SET bit must be 1 while programming these locations to avoid clashes with an
update cycle. Access to time and date information is done through the RAM locations. If
a RAM read from the ten time and date bytes is attempted during an update cycle, the
value read do not necessarily represent the true contents of those locations. Any RAM
writes under the same conditions are ignored.
Note:
The leap year determination for adding a 29th day to February does not take into
account the end-of-the-century exceptions. The logic simply assumes that all years
divisible by 4 are leap years. According to the Royal Observatory Greenwich, years that
are divisible by 100 are typically not leap years. In every fourth century (years divisible
by 400, like 2000), the 100-year-exception is over-ridden and a leap-year occurs. Note
that the year 2100 will be the first time in which the current RTC implementation would
incorrectly calculate the leap-year.
The ICH7 does not implement month/year alarms.
5.12.1
Update Cycles
An update cycle occurs once a second, if the SET bit of register B is not asserted and
the divide chain is properly configured. During this procedure, the stored time and date
are incremented, overflow is checked, a matching alarm condition is checked, and the
time and date are rewritten to the RAM locations. The update cycle will start at least
488 µs after the UIP bit of register A is asserted, and the entire cycle does not take
more than 1984 µs to complete. The time and date RAM locations (0
disconnected from the external bus during this time.
To avoid update and data corruption conditions, external RAM access to these locations
can safely occur at two times. When a updated-ended interrupt is detected, almost 999
ms is available to read and write the valid time and date data. If the UIP bit of Register
A is detected to be low, there is at least 488 µs before the update cycle begins.
Warning:
The overflow conditions for leap years and daylight savings adjustments are based on
more than one date or time item. To ensure proper operation when adjusting the time,
the new time and data values should be set at least two seconds before one of these
conditions (leap year, daylight savings time adjustments) occurs.
146
Functional Description
9) are
®
Intel
ICH7 Family Datasheet