UPD78F1502AGK-GAK-AX Datasheet, PDF (548/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 14 SERIAL ARRAY UNIT
Figure 14-75. Flowchart of UART Transmission (in Continuous Transmission Mode)
Starting UART communication
Setting SAU1EN and SAU0EN
bits of PER0 register to 1
Setting transfer rate by
SPSm register
SMRmn, SCRmn: Setting communication
SDRmn[15:9]: Setting transfer rate
SOLmn:
Setting output data level
SOm, SOEm:
Setting output
Perform initial setting when SEmn = 0.
<1> Select the buffer empty interrupt.
Port manipulation
Writing 1 to SSmn bit
No
Yes
Writing 1 to MDmn0 bit
Writing transmit data to
<2>
TXDq (=SDRmn[7:0])
Buffer empty interrupt
generated?
Yes _<3>
Transmitting next data?
No
Clearing 0 to MDmn0 bit
No
Yes
<4>
TSFmn = 1?
Yes
Transfer end interrupt
No
generated?
Yes <5>
Communication continued?
No
Writing 1 to STmn bit
Clearing SAU1EN and SAU0EN
bits of PER0 register to 0
End of communication
Caution After setting the SAUmEN to 1, be sure to set the SPSm register after 4 or more clocks have
elapsed.
Remark <1> to <5> in the figure correspond to <1> to <5> in Figure 14-74 Timing Chart of UART
Transmission (in Continuous Transmission Mode).
R01UH0004EJ0501 Rev.5.01
532
Jun 20, 2011