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Transmitting Multiprocessor Data: Figure 10.20 shows a typical flow chart for multiprocessor
serial data transmission. After SCI3 initialization, follow the procedure below.
Start
Read bit TDRE in SSR
TDRE = 1?
Set bit MPBT in SSR
Write transmit data to TDR
Continue
transmitting?
Read bit TEND in SSR
TEND = 1?
Break output?
Set PDR = 0 and PCR = 1
Clear bit TE in SCR3 to 0
End
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2
3
2.
3.
1.
To continue transmitting data, read bit
TDRE to make sure it is set to 1, indicating
that data writing is enabled. Then write
the next data to TDR.
When data is written to TDR, TDRE
is automatically cleared to 0.
To output a break signal at the end of data
transmission, first set the port values
PCR = 1 and PDR = 0, then clear bit TE
in SCR3 to 0.
Read the serial status register (SSR), and
after confirming that bit TDRE = 1, set bit
MPBT (multiprocessor bit transmit) in SSR
to 0 or 1, then write transmit data in the
transmit data register (TDR).
No
Yes
No
No
Yes
No
Yes
Yes
When data is written to TDR, TDRE is
automatically cleared to 0.
Figure 10.20 Typical Multiprocessor Data Transmission Flow Chart