R8C/18 Group, R8C/19 Group
19. Usage Notes
Rev.1.30
Apr 14, 2006
Page 223 of 233
REJ09B0222-0130
19.4
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.
Example (when reading receive buffer register):
MOV.W
00A6H,R0
; Read the U0RB register
•
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
#XXH,00A3H
; Write the high-order byte of U0TB register
MOV.B
#XXH,00A2H
; Write the low-order byte of U0TB register