R8C/1A Group, R8C/1B Group
15. Serial Interface
Rev.1.30
Dec 08, 2006
Page 168 of 315
REJ09B0252-0130
15.3
Notes on Serial Interface
• When reading data from the UiRB 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 UiRB
register is read, bits PER and FER in the UiRB register and the RI bit in the UiC1 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
00A6H,R0
; Read the U0RB register
• When writing data to the UiTB 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
#XXH,00A3H
; Write the high-order byte of U0TB register
MOV.B
#XXH,00A2H
; Write the low-order byte of U0TB register
