333
CHAPTER 19 UART0, UART1
19.9.4
Status Flag During Transmit and Receive Operation
RBF is set when the start bit is detected and cleared when a stop bit is detected. The
receive data in UIDR at the RBF clear timing is not yet valid. The data in UIDR becomes
valid at the RDRF set timing.
■
Status Flag During Transmit and Receive Operation
Figure 19.9-7 shows the RBF set timing (Mode 0).
Figure 19.9-7 RBF Set Timing (Mode 0)
Writing the transmission data to UODR0 sets TBF. TBF is cleared when transmission completes.
Figure 19.9-8 TBF Set Timing (Mode 0)
Note:
Receive operation starts after releasing a reset unless the SIN input pin is fixed at "1". Therefore,
before setting the mode, write "0" to RFC in the UMC register to clear any receive flags that have
been set.
Set the communication mode when the RBF and TBF flags in the USR register are "0". The data
transmitted and received during mode setting cannot be guaranteed.
■
EI
2
OS (Extended Intelligent I/O Service)
See the Section "3.7 Extended Intelligent I/O Service (EI2OS)" for details on EI
2
OS.
ST: Start bit
D0 to D7: Data bits
SP: Stop bit
ST
D0
D1
D2 D3 D4
D5 D6 D7
SP
RBF
RDRF, PE, ORFE
SIN0 input
ST: Start bit
D0 to D7: Data bits
SP: Stop bit
ST
D0
D1
D2 D3 D4
D5 D6 D7
SP
SP
TBF
UODR
w
rite
SOT0 output
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: ......