Renesas 16-bit single-chip microcomputer Computer Hardware User Manual


 
Rev.1.02 Jul 01, 2005 page 168 of 314
REJ09B0126-0102
M16C/6N Group (M16C/6NL, M16C/6NN) 14. Serial I/O
Under development
This document is under development and its contents are subject to change.
Figure 14.32 Transmit and Receive Timing in SIM Mode
The above timing diagram applies to the case where data is
received in the direct format.
STPS bit in U2MR register = 0 (1 stop bit)
PRY bit in U2MR register = 1 (even parity)
UFORM bit in U2C0 register = 0 (LSB first)
U2LCH bit in U2C1 register = 0 (no reverse)
U2IRS bit in U2C1 register = 1 (transmit is completed)
Transfer clock
An "L" level is output from TXD2 due to
the occurrence of a parity error
Read the U2RB register
Set to "0" by an interrupt request acknowledgement or a program
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
SP
TC
SP
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
TXD2
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
SP
TC
SP
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
SP
SP
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
D0
D1
D2
D3
D4
D5
D6
D7
ST
P
SP
SP
TXD2
RXD2 pin level
(1)
Parity error signal sent
back from receiving end
Start
bit
Parity
bit
Stop
bit
Write data to U2TB register
Transferred from U2TB register to UART2 transmit register
An "L" level returns due to the
occurrence of a parity error.
The level is
detected by the
interrupt routine.
The level is detected by the
interrupt routine.
The IR bit is set to "1" at the
falling edge of transfer clock
TC = 16 (n + 1) / fi or 16 (n + 1) / fEXT
fi : frequency of U2BRG count source (f1SIO, f2SIO, f8SIO, f32SIO)
fEXT : frequency of U2BRG count source (external clock)
n : value set to U2BRG
TC = 16 (n + 1) / fi or 16 (n + 1) / fEXT
fi : frequency of U2BRG count source (f1SIO, f2SIO, f8SIO, f32SIO)
fEXT : frequency of U2BRG count source (external clock)
n : value set to U2BRG
The above timing diagram applies to the case where data is
transferred in the direct format.
STPS bit in U2MR register = 0 (1 stop bit)
PRY bit in U2MR register = 1 (even parity)
UFORM bit in U2C0 register = 0 (LSB first)
U2LCH bit in U2C1 register = 0 (no reverse)
U2IRS bit in U2C1 register = 1 (transmit is completed)
Start
bit
Parity
bit
Stop
bit
Set to "0" by an interrupt request acknowledgement or a program
Read the U2RB register
Transfer clock
Transmit waveform
from transmitting end
(1) Transmission
(2) Reception
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
"0"
"1"
NOTE:
1. Because TXD2 and RXD2 are connected, a composite waveform, consisting of transmit waveform from the transmitting end and
parity error signal from receiving end, is generated.
NOTE:
1. Because TXD2 and RXD2 are connected, a composite waveform, consisting of the TXD2 output and the parity error signal sent back
from receiving end, is generated.
TE bit in
U2C1 register
TI bit in
U2C1 register
TXEPT bit in
U2C0 register
IR bit in
S2TIC register
RE bit in
U2C1 register
RI bit in
U2C0 register
IR bit in
S2RIC register
RXD2 pin level
(1)