Section 17 Synchronous Serial Communication Unit (SSU)
Rev. 1.00 Mar. 12, 2008 Page 575 of 1178
REJ09B0403-0100
Before switching transmission mode (TE
=
1) or reception mode (RE
=
1) to
transmission/reception mode (TE
=
RE
=
1), clear the TE and RE bits to 0. When starting the
transfer, confirm that the TEND, RDRF, and ORER bits are cleared to 0 before setting the TE or
RE bit to 1.
Yes
Start
Initial setting
[1]
[2]
[1] Initial
setting:
Specify the transmit/receive data format.
[2] Check the SSU state and write transmit data:
Write transmit data to SSTDR after reading and
confirming that the TDRE bit in SSSR is 1. The TDRE
bit is automatically cleared to 0 and transmission/
reception is started by writing data to SSTDR.
[3] Check the SSU state:
Read SSSR confirming that the RDRF bit is 1.
A change of the RDRF bit (from 0 to 1) can be notified
by RXI interrupt.
[4] Receive error processing:
When a receive error occurs, execute the designated
error processing after reading the ORER bit in SSSR.
After that, clear the ORER bit to 0. While the ORER bit is
set to 1, transmission or reception is not resumed.
[5] Procedure for consecutive data transmission/reception:
To continue serial data transmission/reception, confirm
that the TDRE bit is 1 meaning that SSTDR is ready to be
written to. After that, data can be written to SSTDR. The
TDRE bit is automatically cleared to 0 by writing data to
SSTDR.
[4]
[5]
[3]
Transmission/reception started
(TE = 1, RE = 1)
Read TDRE in SSSR.
TDRE = 1?
Yes
Yes
Yes
No
No
No
No
Write transmit data to SSTDR
TDRE automatically cleared
Data transferred from SSTDR to SSTRSR
TDRE set to 1 to start transmission
Read SSSR
RDRF = 1?
ORER = 1?
Read receive data in SSRDR
RDRF automatically cleared
Consecutive data
transmission/reception?
Clear TEND in SSSR to 0
Clear TE and RE in SSER to 0
Error processing
End transmission/reception
Note: Hatching boxes represent SSU internal operations.
Figure 17.9 Flowchart Example of Simultaneous Transmission/Reception (SSU Mode)
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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