HD6432160 RENESAS [Renesas Technology Corp], HD6432160 Datasheet - Page 410

• Manufacturer Part Number: HD6432160
• Description: Hitachi 16-Bit Single-Chip Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

15.5.1
Figure 15.11 shows a sample flowchart for multiprocessor serial data transmission. For an ID
transmission cycle, set the MPBT bit in SSR to 1 before transmission. For a data transmission
cycle, clear the MPBT bit in SSR to 0 before transmission. All other SCI operations are the same
as those in asynchronous mode.
Rev. 2.0, 08/02, page 370 of 788
Multiprocessor Serial Data Transmission
Figure 15.11 Sample Multiprocessor Serial Transmission Flowchart
Clear DR to 0 and set DDR to 1
Write transmit data to TDR and
Read TDRE flag in SSR
Read TEND flag in SSR
Clear TE bit in SCR to 0
Clear TDRE flag to 0
set MPBT bit in SSR
All data transmitted?
Start transmission
Break output?
Initialization
TDRE = 1
TEND = 1
<End>
Yes
Yes
Yes
Yes
No
No
No
No
[1]
[2]
[3]
[4]
[1] SCI initialization:
[2] SCI status check and transmit
[3] Serial transmission continuation
[4] Break output at the end of serial
The TxD pin is automatically
designated as the transmit data
output pin.
After the TE bit is set to 1, a
frame of 1s is output, and
transmission is enabled.
data write:
Read SSR and check that the
TDRE flag is set to 1, then write
transmit data to TDR. Set the
MPBT bit in SSR to 0 or 1.
Finally, clear the TDRE flag to 0.
procedure:
To continue serial transmission,
be sure to read 1 from the TDRE
flag to confirm that writing is
possible, then write data to TDR,
and then 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.
transmission:
To output a break in serial
transmission, set port DDR to 1,
clear DR to 0, and then clear the
TE bit in SCR to 0.