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CHAPTER 15 WATCH TIMER
15.1
Outline of Watch Timer
The Watch Timer consists of the Timer Control register, Sub-second register, Second/
Minute/Hour registers, 1/2 clock divider, 22-bit prescaler and Second/Minute/Hour
counters. The oscillation frequency of the MCU is assumed to be at 4MHz or 5MHz for
the aimed operation of the Watch Timer. The Watch Timer operates as the real-world
timer and provides the real-world time information.
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Block Diagram of Watch Timer
Figure 15.1-1 shows a block diagram of the Watch Timer.
Figure 15.1-1 Block Diagram of Watch Timer
Second Counter
Second/Minute/Hour register
CO
1/2 Clock
Divider
Oscillation
clock
21bit Prescaler
Sub-second
register
CO
EN
WOT
OE
OE
6bits
Minute Counter
CO
6bits
Hour Counter
CO
5bits
LOAD
CI
EN
UPDT
ST
INTE0
INT0
INTE1
INT1
INTE2
INT2
INT3
INT3
IRQ
22-bit prescaler
Summary of Contents for MB90390 Series
Page 2: ......
Page 4: ......
Page 17: ...xiii APPENDIX D List of Interrupt Vectors 690 INDEX 695 ...
Page 18: ...xiv ...
Page 132: ...104 CHAPTER 5 CLOCKS ...
Page 152: ...124 CHAPTER 6 CLOCK MODULATOR ...
Page 210: ...182 CHAPTER 11 TIME BASE TIMER ...
Page 218: ...190 CHAPTER 12 WATCHDOG TIMER ...
Page 264: ...236 CHAPTER 14 16 BIT RELOAD TIMER WITH EVENT COUNT FUNCTION ...
Page 274: ...246 CHAPTER 15 WATCH TIMER ...
Page 306: ...278 CHAPTER 17 DTP EXTERNAL INTERRUPTS ...
Page 338: ...310 CHAPTER 18 8 10 BIT A D CONVERTER ...
Page 364: ...336 CHAPTER 19 UART0 UART1 ...
Page 398: ...370 CHAPTER 20 UART2 UART3 Figure 20 5 2 ORE Set Timing Receive data RDRF ORE ...
Page 432: ...404 CHAPTER 20 UART2 UART3 ...
Page 482: ...454 CHAPTER 22 SERIAL I O ...
Page 560: ...532 CHAPTER 24 STEPPING MOTOR CONTROLLER ...
Page 582: ...554 CHAPTER 27 ROM MIRRORING MODULE ...
Page 632: ...604 CHAPTER 29 EXAMPLES OF SERIAL PROGRAMMING CONNECTION ...
Page 722: ...694 APPENDIX ...
Page 723: ...695 INDEX The index follows on the next page This is listed in alphabetic order ...
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