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CHAPTER 11 TIME-BASE TIMER
11.3
Operations of Time-base Timer
The time-base timer functions as a watch-dog timer clock source, timer for oscillation
stabilization wait time, and interval timer for generating interrupts at specified intervals.
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Time-base Counter
The time-base counter consists of an 18-bit counter for a clock generated by dividing the source oscillation
input by two. This clock is used to generate the machine clock. While the source oscillation is input, the
time-base counter keeps counting. The time-base counter is cleared by a power-on reset, transition to stop
or writing "0" to the TBR bit of the TBTC register.
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Interval Interrupt Function
Interrupts are generated at specified intervals according to the carry signals of the time-base counter. The
TBOF flag is set at the intervals specified with the TBC1 and TBC0 bits of the TBTC register. The flag is
written to reference to the time at which the time-base timer is cleared last.
Upon transition to stop mode, the time-base timer is used as a timer for oscillation stabilization wait time
upon recovery. Therefore, the TBOF flag is immediately cleared upon mode transition.
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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