Renesas 7700 FAMILY, User Manual

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SERIAL I/O
7751 Group User’s Manual 7–21
7.3 Clock synchronous serial I/O mode
Fig. 7.3.1 Initial setting example for relevant registers when transmitting
UART0 transmit buffer register (Address 32
16
)
UART1 transmit buffer register (Address 3A
16
)
b7 b0
Set transmit data here.
1
UART0 transmit/receive control register 1 (Address 35 16 )
UART1 transmit/receive control register 1 (Address 3D
16
)
b7 b0
Transmit enable bit
1: Transmission enabled
(In the case of selecting the
CTS
function, transmission starts
when the CTS
i
pin’s input level is “L.”)
UART0 transmit/receive control register 0 (Address 34
16
)
UART1 transmit/receive control register 0 (Address 3C
16
)
b7 b0
BRG count source select bits
0 0 : f
2
/f
4
0 1 : f
16
/f
32
1 0 : f
64
/f
128
1 1 : f
512
/f
1024
b1 b0
1 0 0 0
UART0 transmit/receive mode register (Address 30
16
)
UART1 transmit/receive mode register (Address 38
16
)
b7 b0
Internal/External clock select bit
0: Internal clock
1: External clock
✕
: It may be either “0” or “1.”
Clock synchronous serial I/O mode
✕ ✕ ✕
UART0 transmit interrupt control register (Address 71
16
)
UART1 transmit interrupt control register (Address 73
16
)
b7 b0
Interrupt priority level select bits
When using interrupts, set these bits to
level 1
-
7. When disabling interrupts, set
these bits to level 0.
UART0 baud rate register (BRG0) (Address 31
16
)
UART1 baud rate register (BRG1) (Address 39
16
)
b7 b0
Set to “00
16
” to “FF
16
.”
✽
Necessary only when internal clock is
selected.
Transmission starts.
CTS / RTS select bit
0:
CTS
function selected.
1: RTS function selected ( CTS function disabled).
Transfer format select bit
0: LSB first
1: MSB first