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7703 GROUP
7702/7703 Group User’s Manual
20–9
20.4 Functional description
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(2) CTS1/RTS1 pin
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The M37703 does not have the CTS1/RTS1 pin. Fix the CTS/RTS select bit (bit 2 at address 3C16)
to “1”.
Figure 20.4.5 shows the structure of the UART1 transmit/receive control register 0 and Figure 20.4.6
shows the structure of the port P8 direction register when using UART1.
Fix this bit to “1.”
Bit
1
BRG count source select bits
Bit name
At reset
RW
Functions
b7
b6
b5
b4
b3
b2
b1
b0
0 0 : f2
0 1 : f16
1 0 : f64
1 1 : f512
UART1 transmit/receive control register 0 (Address 3C16)
b1 b0
Transmit register empty flag
0 : Data present in transmit register.
(During transmitting)
1 : No data present in transmit register.
(Transmitting completed)
1
0
7 to 4
0
2
RW
RO
3
RW
Nothing is assigned.
Undefined
–
1
Fig. 20.4.5 Structure of UART1 transmit/receive control register 0
Fig. 20.4.6 Structure of port P8 direction register when using UART1
Bit
Corresponding pin
Functions
0
1
2
3
4
5
6
7
CTS0
/RTS0 pin
RxD0 pin
TxD0 pin
RxD1 pin
0 : Input mode
1 : Output mode
When using pin P82 as serial data
input pin (RxD0),set bit 2 to “0.”
Port P8 direction register (Address 1416)
b1
b0
b2
b3
b4
b5
b6
b7
CLK0 pin
TxD1 pin
At reset
RW
0
RW
When using pin P86 as serial data
input pin (RxD1),set bit 6 to “0.”
Fix these bits to “1.”
11
: Bits 0 to 3 are not used in UART1.