Renesas Hitachi H8S/2191, Hardware Manual

Page: 507 / 1065

Rev. 2.0, 11/00, page 480 of 1037
No
< End >
[1]
Yes
Initialization
Start transmission
Read TDRE flag in SSR1 [2]
Write transmit data to TDR1
and set MPBT bit in SSR1
No
Yes
No
Yes
Read TEND flag in SSR1
[3]
No
Yes
[4]
Clear PDR to 0 and set PCR to 1
Clear TE bit in SCR1 to 0
TDRE=1
Transmission end?
TEND=1
Break output?
Clear TDRE flag to 0
SCI1 initialization:
The SO1 pin is automatically designated as
the transmit data output pin.
SCI1 status check and transmit data write:
Read SSR1 and check that the TDRE flag
is set to 1, then write transmit data to
TDR1. Set the MPBT bit in SSR1 to 0 or 1.
Finally, clear the TDRE flag to 0.
Serial transmission continuation procedure:
To continue serial transmission, be sure to
read 1 from the TDRE flag to confirm that
writing is possible, then write data to TDR1,
and then clear the TDRE flag to 0.
Break output at the end of serial
transmission:
To output a break in serial transmission, set
the port PCR to 1, clear PDR to 0, then
clear the TE bit in SCR1 to 0.
[1]
[2]
[3]
[4]
Figure 23.10 Sample Multiprocessor Serial Transmission Flowchart