3820_03 Datasheet, PDF (208/349 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.5 Serial I/O1
2.5.3 Related registers
Figure 2.5.13 shows the memory allocation of serial
I/O1-related registers. They are the transmit/receive
buffer register, serial I/O1 status register, serial
I/O1 control register, and UART control register.
(1) Transmit/receive buffer register (TB/RB)
This register (address 001816) is used to write
serial I/O1 transmit data or to read receive data
(used for both the clock synchronous mode and
the UART mode).
For data transmission, transmit data is written
into this register.
Received data is obtained by reading out this
register.
Address
001816
001916
001A16
001B16
Transmit/receive buffer register
(TB/RB)
Serial I/O1 status register
(SIO1STS)
Serial I/O1 control register
(SIO1CON)
UART control register
(UARTCON)
Fig. 2.5.13 Memory allocation of serial I/O1-related
registers
Transmit/receive buffer register
b7 b6 b5 b4 b3 b2 b1 b0
Transmit/receive buffer register (TB/RB) [Address 1816]
B
Functions
At reset R W
0 _{At transmit}
?
to _{•Set “0016 to FF16” as transmit data.}
7 _{•The transmit data is transferred automatically}
to transmit shift register by writing transmit
data.
At receive
•When all receive data has been input into the
receive shift register, the receive data is auto-
matically transferred to this register.
Fig. 2.5.14 Structure of transmit/receive buffer register
3820 GROUP USER’S MANUAL
2–121