Renesas R8C/20 User Manual

R8C/20 Group, R8C/21 Group 15. Serial Interface
Rev.2.00 Aug 27, 2008 Page 278 of 458
REJ09B0250-0200
Figure 15.10 Transmit Timing in UART Mode
D0
TC
D1 D2 D3 D4 D5 D6 D7 P
SP
ST D0 D1 D2 D3 D4 D5 D6 D7 P SPST D0 D1ST
D0
TC
D1 D2 D3 D4 D5 D6 D7 D8
SP SP
ST D0 D1 D2 D3 D4 D5 D6 D7 D8 SP SPST D0 D1ST
Transfer clock
TE bit in UiC1
register
TXDi
Set to 0 when interrupt request is acknowledged, or set by a program
• Transmit timing when transfer data is 8 bits long (parity enabled, 1 stop bit)
Write data to UiTB register
TC=16 (n + 1) / fj or 16 (n + 1) / fEXT
fj: Frequency of UiBRG count source (f1, f8, f32)
fEXT: Frequency of UiBRG count source (external clock)
n: Setting value to UiBRG register
i = 0 or 1
The above timing diagram applies under the following conditions:
• PRYE bit in UiMR register = 1 (parity enabled)
• STPS bit in UiMR register = 0 (1 stop bit)
• UiIRS bit in UiC1 register = 1 (an interrupt request is generated when transmit completes)
Start
bit
Parity
bit
Stop pulsing
because the TE bit is set to 0
TXDi
Write data to UiTB register
Transfer from UiTB register to UARTi transmit register
TI bit in UiC1
register
1
0
1
0
1
0
1
0
TXEPT bit in
UiC0 register
IR bit SiTIC
register
Stop
bit
• Transmit timing when transfer data is 9 bits long (parity disabled, 2 stop bits)
1
0
Stop
bit
Stop
bit
Start
bit
Transfer clock
TE bit in UiC1
register
TI bit in UiC1
register
TXEPT bit in
UiC0 register
IR bit in SiTIC
register
1
0
1
0
1
0
Transfer from UiTB register to UARTi transmit register
TC=16 (n + 1) / fj or 16 (n + 1) / fEXT
fj: Frequency of UiBRG count source (f1, f8, f32)
fEXT: Frequency of UiBRG count source (external clock)
n: Setting value to UiBRG register
i = 0 or 1
Set to 0 when interrupt request is acknowledged, or set by a program
The above timing diagram applies under the following conditions:
• PRYE bit in UiMR register = 0 (parity disabled)
• STPS bit in UiMR register = 1 (2 stop bits)
• UiIRS bit in UiC1 register = 0 (an interrupt request is generated when transmit buffer is empty)

Renesas R8C/20 Specifications

General

Brand	Renesas
Model	R8C/20
Category	Control Unit
Language	English