Datasheet
Section 22 Synchronous Serial Communication Unit (SSU)
Page 788 of 982 REJ09B0465-0300 Rev. 3.00
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
Ye s
Start
Initialization
Dummy read on SSRDR[1]
[2]
[3]
[4]
[5]
[6]
[7]
[1] After setting each register in the SSU,
dummy read on SSRDR is performed
and reception is started.
[2] Determine whether the last one byte of
data is received. When the last one byte
of data is received, set to stop reception
after the data is received.
[3][6] When a receive error occurs, clear the
ORER flag to 0 after the ORER flag in
SSSR is read and an appropriate error
processing is performed. When the ORER
flag is set to 1, transmission/reception
cannot be started again.
[4] Confirm that the RDRF bit is 1. If the RDRF
bit is 1, receive data in SSRDR is read. If the
SSRDR bit is read, the RDRF bit is automatically
cleared.
[5] Before the last one byte of data is received,
set the RSSTP bit to 1 and reception is stopped
after the data is received.
[7] Confirm that the RDRF bit is 1. To end
reception, clear the RE and RSSTP bits to
0 and then read the last receive data. If the
SSRDR bit is read before clearing the RE bit,
reception is started again.
Last reception?
Read ORER
ORER = 1?
Read RDRF
RDRF = 1?
Read receive data
in SSRDR
Ye s
Ye s
No
No
Ye s
Ye s
No
No
No
Set RSSTP to 1
Read ORER
ORER = 1?
Read RDRF
RDRF = 1?
RE = 0, RSSTP = 0
Read receive data
in SSRDR
End
Overrun error
processing
Figure 22.8 Sample Serial Reception Flowchart (MSS = 1)