Oki ML63611, User Manual

Page: 161 / 271

ML63611 User’s Manual
Chapter 12 Serial Port (SIO)
12 – 9
OPTION B (D): 1.5 V (3.0 V), With regulator
circuit for LCD bias
OPTION A (C): 1.5 V (3.0 V), Without regulator
circuit for LCD bias
(5) Receive register
The receive register is the shift register that handles shift operation at receive. It is initialized to 00H at
system reset. It cannot be directly accessed by the CPU. When a receive operation is complete, the data read
into the receive register is transferred to SRBUFL/H, and at the same time the receive interrupt request signal
(SRINT) is generated.
(6) Receive buffer registers (SRBUFL, SRBUFH)
SRBUFL and SRBUFH are 4-bit special function registers (SFRs) used to hold the received data in serial
port reception. SRBUFL and SRBUFH are initialized to “0” at system reset.
When receive operation is completed the contents of the receive register are sent to SRBUFL/H, and the
receive interrupt request (SRINT) is generated. The contents of SRBUFL/H are held until the next receive
operation is completed.
If data from a prior receive operation is in SRBUFL/H and new data is received, an overrun error will result.
When an overrun error is generated, new received data cannot be loaded into SRBUFL/H.
RB3 RB2 RB1 RB0
SRBUFL (0A8H)
(R)
bit 3 bit 2 bit 1 bit 0
RB7 RB6 RB5 RB4
SRBUFH (0A9H)
(R)
bit 3 bit 2 bit 1 bit 0