
127
CHAPTER 7 RESETS
●
External reset
An external reset is generated by the "L" level input to an external reset pin (RST pin). The minimum
required period of the "L" level is 16 machine cycles (16/
φ
). The oscillation stabilization wait time is not
required for external resets.
In the MB90390 series the external reset has to be Min 100
μ
s for wake-up from Main-Time base timer
mode and Min 100
μ
s + Oscillation time of osci 16 machine cycles for wake-up from Stop mode.
Refer to the AC characteristics section of the data sheet.
Reference:
If the reset cause is generated during a write operation (during the execution of a transfer instruction
such as MOV), the CPU waits for the reset to be cleared after completion of the instruction only for
reset requests via the RST pin. Therefore, the normal write operation is completed even though a reset
is input concurrently.
Note that a reset may prevent the data transfer requested by a string-processing instruction (such as
MOVS) from being completed because the reset is accepted before a specified number of bytes are
transferred.
●
Software reset
A software reset is an internal reset generated by writing "0" to the RST bit of the low-power consumption
mode control register (LPMCR). The oscillation stabilization wait time is not required for a software reset.
●
Watchdog timer reset
A watchdog timer reset is generated by a watchdog timer overflow that occurs when "0" is written to the
WTE bit of the watchdog timer control register (WDTC) within a given time after the watchdog timer is
activated. The oscillation stabilization wait time can be set by the clock selection register (CKSCR).
●
Power-on reset
A power-on reset is generated when the power is turned on. In this case the oscillation stabilization wait
time is fixed to at 2
18
HCLK cycles (approx. 65.54 ms at 4MHz source oscillation). When the oscillation
stabilization wait time has elapsed, the reset is executed.
Reference Definition of clocks
HCLK: Oscillation clock
MCLK: Main clock
φ
: Machine clock (CPU operating clock)
1/
φ
: Machine cycle (CPU operating clock period)
See "CHAPTER 5 CLOCKS", for details on machine clocks.
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 ...
Page 740: ......