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CHAPTER 17 UART
17.5.2
Transmission Interrupt Generation and Flag Set Timing
A transmission interrupt is generated when the next piece of data is ready to be written
to the output data register (SODR0/SODR1).
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Transmission Interrupt Heneration and Flag Set Timing
The transmission data empty flag bit (SSR0/SSR1: TDRE) is set to "1" when data written to the output data
register (SODR0/SODR1) is transferred to the transmission shift register, and the next piece of data is
ready to be written. TDRE is cleared to "0" when transmission data is written to SODR0/SODR1. Figure
17.5-2 shows the transmission operation and flag set timing.
Figure 17.5-2 Transmission Operation and Flag Set Timing
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Transmission interrupt request generation timing
If the TDRE flag is set to "1" when a transmission interrupt is enabled (SSR0/SSR1: TIE = 1), transmission
interrupt requests (#38 and #40) are generated.
Note:
A transmission completion interrupt is generated immediately after the transmission interrupts are
enabled (TIE = 1) because the TDRE bit is set to "1" as its initial value. TDRE is a read-only bit that
can be cleared only by writing new data to the output data register (SODR0/SODR1). Carefully
specify the transmission interrupt enable timing.
ST D0
D1 D2
D3
D4 D5
D6 D7
SP
A/D
SP ST D0
D1 D2
D3
TDRE
ST: Start bit
D0 to D7: Data bits
SP: Stop bit
SODR write
SOT interrupt
SOT output
An interrupt request is issued to the CPU.
A/D: Address/data multiplexer
D0
D1 D2
D3
D4 D5
D6 D7
D0 D1
D2
D3
TDRE
D4 D5
D6 D7
SODR write
SOT interrupt
SOT output
An interrupt request is issued to the CPU.
[Operation modes 0 and 1]
[Operation mode 2]
Summary of Contents for MB90460 Series
Page 1: ...The following document contains information on Cypress products ...
Page 3: ......
Page 5: ......
Page 9: ...iv ...
Page 41: ...22 CHAPTER 1 OVERVIEW ...
Page 45: ...26 CHAPTER 2 NOTES ON HANDLING DEVICES ...
Page 83: ...64 CHAPTER 3 CPU ...
Page 95: ...76 CHAPTER 4 RESET ...
Page 107: ...88 CHAPTER 5 CLOCK ...
Page 131: ...112 CHAPTER 6 LOW POWER CONSUMPTION MODE ...
Page 175: ...156 CHAPTER 7 INTERRUPT ...
Page 181: ...162 CHAPTER 8 MODE SETTING ...
Page 223: ...204 CHAPTER 9 I O PORT ...
Page 237: ...218 CHAPTER 10 TIME BASE TIMER ...
Page 247: ...228 CHAPTER 11 WATCHDOG TIMER ...
Page 275: ...256 CHAPTER 12 16 BIT RELOAD TIMER ...
Page 373: ...354 CHAPTER 14 MULTI FUNCTIONAL TIMER ...
Page 485: ...466 CHAPTER 16 PWC Timer ...
Page 531: ...512 CHAPTER 17 UART ...
Page 559: ...540 CHAPTER 19 DELAYED INTERRUPT GENERATOR MODULE ...
Page 589: ...570 CHAPTER 20 8 10 BIT A D CONVERTER ...
Page 601: ...582 CHAPTER 21 ROM CORRECTION FUNCTION ...
Page 633: ...614 CHAPTER 23 512K 1024K BIT FLASH MEMORY ...
Page 645: ...626 CHAPTER 24 EXAMPLE OF F2 MC 16LX MB90F462 F462A F463A CONNECTION FOR SERIAL WRITING ...
Page 715: ...696 APPENDIX ...
Page 716: ...697 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 739: ......