130
CHAPTER 7 RESETS
7.3
External Reset Pin
The external reset pin (RST pin) is an input pin used exclusively for a reset. Inputting an
"L" level signal generates an internal reset. For the MB90390 series, resets are
generated in synchronization with the CPU operating clock. However, the I/O port pins
are affected by the external reset pin (RST pin) in an asynchronous manner.
■
Block Diagrams of the External Reset Pin
●
Block diagram of internal reset
Figure 7.3-1 Block Diagram of Internal Reset
Note:
Inputs to the RST are accepted during cycles in which memory is not affected to prevent memory
from being destroyed by a reset during a write operation.
A clock is required to initialize the internal circuit. In particular, an operation with an external clock
requires clock input together with reset input.
RST
Pin
P-ch
N-ch
Input
buffer
CPU operating clock
(PLL multiplier circuit
w
ith an
HCLK frequency divided by 2)
Synchronization
circuit
CPU
Peripheral
functions
I/O port or
other pin
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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