Notes On Serial Interface - Renesas R8C Series User Manual

R8C/1A Group, R8C/1B Group
20.4

Notes on Serial Interface

• When reading data from the U0RB register either in the clock asynchronous serial I/O mode or in the clock
synchronous serial I/O mode. Ensure the data is read in 16-bit units. When the high-order byte of the U0RB
register is read, bits PER and FER in the U0RB register and the RI bit in the U0C1 register are set to 0.
To check receive errors, read the UiRB register and then use the read data.
Example (when reading receive buffer register):
MOV.W
• When writing data to the U0TB register in the clock asynchronous serial I/O mode with 9-bit transfer data
length, write data to the high-order byte first then the low-order byte, in 8-bit units.
Example (when reading transmit buffer register):
MOV.B
MOV.B
Rev.1.30 Dec 08, 2006
REJ09B0252-0130
00A6H,R0 ; Read the U0RB register
#XXH,00A3H ; Write the high-order byte of U0TB register
#XXH,00A2H ; Write the low-order byte of U0TB register
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20. Usage Notes