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17. Serial I/O (Clock Synchronous Serial I/O)
)
T
5
8
/
C
2
3
M
,
5
8
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C
2
3
M
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G
5
8
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2
3
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D0 D1
D2 D3
D4 D5 D6
D7
D0 D1 D2 D3
D4 D5 D6
D7
D0 D1
D2 D3 D4 D5 D6 D7
Tc
TCLK
Pulse stops because the TE bit is set to "0"
Data is set in the UiTB register
Transfer Clock
TE bit in UiC1
register
TI bit in UiC1
register
CLKi
TxDi
TXEPT bit in
UiC0 register
"H"
"L"
CTSi
IR bit in SiTIC
register
"0"
"1"
Pulse stops because an "H"
signal is applied to CTSi
Data is transferred from the UiTB register to the UARTi transmit register
Set to "0" by an interrupt request acknowledgement or by program
TC=TCLK=2(m+1)/fj
fj : Count source frequency set in the UiBRG register (f1, f8, f2n(1))
m : Setting value of the UiBRG register
i = 0 to 4
NOTES:
1. The CNT3 to CNT0 bits in the TCSPR register select no division (
n=0) or divide-by-2n (n=1 to 15).
The above applies to the following settings:
The CKDIR bit in the UiMR register is set to "0" (internal clock selected)
The CRD bit in the UiC0 register is set to "0" (RTS/CTS function enabled)
The CRS bit is set to "0" (CTS function selected)
The CKPOL bit the in UiC0 register is set to "0" (data transmitted on the
falling edge of the transfer clock)
The UiIRS bit in the UiC1 register is set to "0" (no data in the UiTB register)
(1) Transmit Timing (Internal clock selected)
"0"
"1"
"0"
"1"
"0"
"1"
Dummy data is set in the UiTB register
TE bit in UiC1
register
TI bit in UiC1
register
CLKi
RxDi
RI bit in UiC1
register
RTSi
RE bit in UiC1
register
Data is transferred from the UiTB register to the UARTi transmit register
Read by the UiRB register
The above applies to the following settings:
The CKDIR bit in the UiMR register is set to "1" (external clock selected)
The CRD bit in the UiC0 register is set to "0" (RTS/CTS function enabled)
The CRS bit is set to "1" (RTS function selected)
The CKPOL bit in the UiC0 register is set to "0"
(Data is received on the rising edge of the transfer clock)
IR bit in SiRIC
register
Set to "0" by an interrupt request acknowledgement or by
program
1 / fEXT
D0 D1
D2 D3 D4 D5 D6 D7
D0
D1 D2
D3 D4
D5
D0 D1 D2 D3 D4 D5
D7
D6
OER bit in UiRB
register
D6
Meet the following conditions while an "H" signal is applied to
the CLKi pin before receiving data:
Set the TE bit in the UiC1 register to "1" (transmit enable)
Set the RE bit in the UiC1 register to "1" (receive enable)
Write dummy data to the UiTB register
fEXT: External clock frequency
i=0 to 4
(2) Receive Timing (External clock selected)
"H"
"L"
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
An "L" signal is applied when
the UiRB register is read
Received data is taken in
Date is transferred from the UARTi
receive register to the UiRB register
Figure 17.10 Transmit and Receive Operation