Section 13 Serial Communication Interface (SCI)
Rev. 1.00 Mar. 12, 2008 Page 474 of 1178
REJ09B0403-0100
Yes
<End>
[1]
No
Initialization
Start transmission/reception
[5]
Error processing
[3]
Read receive data in RDR, and
clear RDRF flag in SSR to 0
No
Yes
ORER = 1
All data received?
[2]
Read TDRE flag in SSR
No
Yes
TDRE = 1
Write transmit data to TDR and
clear TDRE flag in SSR to 0
No
Yes
RDRF = 1
Read ORER flag in SSR
[4]
Read RDRF flag in SSR
Clear TE and RE bits in SCR to 0
[1] SCI
initialization:
The TxD pin is designated as the
transmit data output pin, and the RxD
pin is designated as the receive data
input pin, enabling simultaneous
transmit and receive operations.
[2] SCI status check and transmit data
write:
Read SSR and check that the TDRE
flag is set to 1, then write transmit
data to TDR and clear the TDRE flag
to 0.
Transition of the TDRE flag from 0 to
1 can also be identified by a TXI
interrupt.
[3] Receive error processing:
If a receive error occurs, read the
ORER flag in SSR, and after
performing the appropriate error
processing, clear the ORER flag to 0.
Transmission/reception cannot be
resumed if the ORER flag is set to 1.
[4] SCI status check and receive data
read:
Read SSR and check that the RDRF
flag is set to 1, then read the receive
data in RDR and clear the RDRF flag
to 0. Transition of the RDRF flag from
0 to 1 can also be identified by an RXI
interrupt.
[5] Serial transmission/reception
continuation procedure:
To continue serial transmission/
reception, before the MSB (bit 7) of
the current frame is received, finish
reading the RDRF flag, reading RDR,
and clearing the RDRF flag to 0. Also,
before the MSB (bit 7) of the current
frame is transmitted, read 1 from the
TDRE flag to confirm that writing is
possible. Then write data to TDR and
clear the TDRE flag to 0.
However, the TDRE flag is checked
and cleared automatically when the
DTC is initiated by a transmit data
empty interrupt (TXI) request and
writes data to TDR. Similarly, the
RDRF flag is cleared automatically
when the DTC is initiated by a receive
data full interrupt (RXI) and reads
data from RDR.
Note: When switching from transmit or receive operation to simultaneous
transmit and receive operations, first clear the TE bit and RE bit to 0,
then set both these bits to 1 simultaneously.
Figure 13.20 Sample Flowchart of Simultaneous Serial Transmission and Reception
Summary of Contents for H8S Family
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Page 70: ...Section 1 Overview Rev 1 00 Mar 12 2008 Page 22 of 1178 REJ09B0403 0100...
Page 108: ...Section 2 CPU Rev 1 00 Mar 12 2008 Page 60 of 1178 REJ09B0403 0100...
Page 116: ...Section 3 MCU Operating Modes Rev 1 00 Mar 12 2008 Page 68 of 1178 REJ09B0403 0100...
Page 152: ...Section 5 Interrupt Controller Rev 1 00 Mar 12 2008 Page 104 of 1178 REJ09B0403 0100...
Page 206: ...Section 6 Bus Controller BSC Rev 1 00 Mar 12 2008 Page 158 of 1178 REJ09B0403 0100...
Page 420: ...Section 9 14 Bit PWM Timer PWMX Rev 1 00 Mar 12 2008 Page 372 of 1178 REJ09B0403 0100...
Page 476: ...Section 12 Watchdog Timer WDT Rev 1 00 Mar 12 2008 Page 428 of 1178 REJ09B0403 0100...
Page 552: ...Section 14 CRC Operation Circuit CRC Rev 1 00 Mar 12 2008 Page 504 of 1178 REJ09B0403 0100...
Page 712: ...Section 18 I2 C Bus Interface IIC Rev 1 00 Mar 12 2008 Page 664 of 1178 REJ09B0403 0100...
Page 804: ...Section 19 LPC Interface LPC Rev 1 00 Mar 12 2008 Page 756 of 1178 REJ09B0403 0100...
Page 838: ...Section 20 Ethernet Controller EtherC Rev 1 00 Mar 12 2008 Page 790 of 1178 REJ09B0403 0100...
Page 964: ...Section 24 RAM Rev 1 00 Mar 12 2008 Page 916 of 1178 REJ09B0403 0100...
Page 1066: ...Section 25 Flash Memory Rev 1 00 Mar 12 2008 Page 1018 of 1178 REJ09B0403 0100...
Page 1098: ...Section 26 Boundary Scan JTAG Rev 1 00 Mar 12 2008 Page 1050 of 1178 REJ09B0403 0100...
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