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Rev. 3.0, 04/02, page x of xxxviii
10.8.3 Notes on Register Access................................................................................. 257
Using the WDT............................................................................................................ 258
10.9.1 Standby Clearing Procedure............................................................................. 258
10.9.2 Frequency Changing Procedure ....................................................................... 258
10.9.3 Using Watchdog Timer Mode.......................................................................... 259
10.9.4 Using Interval Timer Mode.............................................................................. 259
10.10 Notes on Board Design ................................................................................................ 260
10.9
Section 11 Realtime Clock (RTC)
.............................................................................. 263
11.1
Overview..................................................................................................................... 263
11.1.1 Features........................................................................................................... 263
11.1.2 Block Diagram................................................................................................ 264
11.1.3 Pin Configuration............................................................................................ 265
11.1.4 Register Configuration..................................................................................... 265
11.2
Register Descriptions................................................................................................... 267
11.2.1 64 Hz Counter (R64CNT)................................................................................ 267
11.2.2 Second Counter (RSECCNT)........................................................................... 267
11.2.3 Minute Counter (RMINCNT) .......................................................................... 268
11.2.4 Hour Counter (RHRCNT)................................................................................ 268
11.2.5 Day-of-Week Counter (RWKCNT).................................................................. 269
11.2.6 Day Counter (RDAYCNT).............................................................................. 270
11.2.7 Month Counter (RMONCNT).......................................................................... 270
11.2.8 Year Counter (RYRCNT)................................................................................ 271
11.2.9 Second Alarm Register (RSECAR).................................................................. 272
11.2.10 Minute Alarm Register (RMINAR).................................................................. 272
11.2.11 Hour Alarm Register (RHRAR)....................................................................... 273
11.2.12 Day-of-Week Alarm Register (RWKAR)......................................................... 273
11.2.13 Day Alarm Register (RDAYAR) ..................................................................... 274
11.2.14 Month Alarm Register (RMONAR)................................................................. 275
11.2.15 RTC Control Register 1 (RCR1)...................................................................... 275
11.2.16 RTC Control Register 2 (RCR2)...................................................................... 277
11.2.17 RTC Control Register (RCR3) and Year-Alarm Register (RYRAR)
(SH7751R Only) ............................................................................................. 280
11.3
Operation..................................................................................................................... 281
11.3.1 Time Setting Procedures.................................................................................. 281
11.3.2 Time Reading Procedures................................................................................ 282
11.3.3 Alarm Function............................................................................................... 284
11.4
Interrupts..................................................................................................................... 285
11.5
Usage Notes................................................................................................................. 285
11.5.1 Register Initialization ...................................................................................... 285
11.5.2 Carry Flag and Interrupt Flag in Standby Mode................................................ 285
11.5.3 Crystal Oscillator Circuit................................................................................. 285