Datasheet

Table Of Contents
Page xxviii of liv REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
Section 20 Masked ROM................................................................................................... 665
20.1 Features............................................................................................................................. 665
Section 21 Clock Pulse Generator................................................................................... 667
21.1 Register Descriptions........................................................................................................ 668
21.1.1 System Clock Control Register (SCKCR)........................................................ 668
21.1.2 Low-Power Control Register (LPWRCR) ........................................................ 670
21.2 System Clock Oscillator ................................................................................................... 671
21.2.1 Connecting a Crystal Resonator........................................................................ 671
21.2.2 Connecting a Ceramic Resonator (H8S/2215T) ............................................... 672
21.2.3 Inputting an External Clock.............................................................................. 672
21.3 Duty Adjustment Circuit................................................................................................... 674
21.4 Medium-Speed Clock Divider.......................................................................................... 674
21.5 Bus Master Clock Selection Circuit.................................................................................. 674
21.6 USB Operating Clock (48 MHz) ...................................................................................... 675
21.6.1 Connecting a Ceramic Resonator...................................................................... 675
21.6.2 Inputting an 48-MHz External Clock................................................................ 675
21.6.3 Pin Handling when 48-MHz External Clock Is Not Needed
(On-chip PLL Circuit Is Used) ......................................................................... 676
21.7 PLL Circuit for USB......................................................................................................... 677
21.8 Usage Notes...................................................................................................................... 678
21.8.1 Note on Crystal Resonator................................................................................ 678
21.8.2 Note on Board Design....................................................................................... 678
21.8.3 Note on Switchover of External Clock ............................................................. 678
Section 22 Power-Down Modes....................................................................................... 681
22.1 Register Descriptions........................................................................................................ 684
22.1.1 Standby Control Register (SBYCR) ................................................................. 684
22.1.2 Module Stop Control Registers A to C (MSTPCRA to MSTPCRC)................ 686
22.2 Medium-Speed Mode ....................................................................................................... 688
22.3 Sleep Mode....................................................................................................................... 689
22.3.1 Transition to Sleep Mode.................................................................................. 689
22.3.2 Exiting Sleep Mode .......................................................................................... 689
22.4 Software Standby Mode.................................................................................................... 690
22.4.1 Transition to Software Standby Mode .............................................................. 690
22.4.2 Clearing Software Standby Mode..................................................................... 690
22.4.3 Setting Oscillation Stabilization Time after Clearing
Software Standby Mode.................................................................................... 691
22.4.4 Software Standby Mode Application Example................................................. 692