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CHAPTER 22 SERIAL I/O
22.4.2
Serial I/O Operation
There are four serial I/O operation statuses:
• STOP
• Halt
• SDR Read/Write standby
• Transfer
■
Serial I/O Operation
●
STOP
The STOP state is initiated upon RESET or when "1" is written to the STOP bit of SMCS. The shift
counter is initialized, and "0" is written to SIR.
To resume operation from the STOP state, write "0" to STOP and "1" to STRT. (These two bits can be
written to simultaneously.) Since the STOP bit overrides the STRT bit, transfer cannot be started by writing
"1" to STRT while "1" is written to STOP.
●
Halt
When transfer is completed while the MODE bit is "0", "0" is set to BUSY and "1" is set to SIR of the
SMCS, the counter is initialized, and the system stops. To resume operation from the stop state, write "1" to
STRT.
●
Serial data register Read/Write standby
When transfer is completed while the MODE bit is "1", "0" is set to BUSY and "1" is set to SIR of the
SMCS, and the system enters the serial data register Read/Write standby state. If the interrupt enable flag is
set, an interrupt signal is output from this block.
To resume operation from Read/Write standby state, read or write to the serial data register. This sets the
BUSY bit to "1" and starts data transfer.
●
Transfer
"1" is set to the BUSY bit and serial transfer is being performed. According to the MODE bit, the halt state
or Read/Write standby state comes next.
Figure 22.4-1 is a diagram of the operation transitions.
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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