c. Data transfer operations
SCI3 initialization
•
Data transfer on SCI3 first of all requires that SCI3 be initialized as described in “SCI
initialization” under 10.3.3, 2. c. Data transfer operations, and shown in figure 10-10.
•
Transmitting
Figure 10-16 shows an example of a flowchart for data transmission. This procedure should be
followed for data transmission after initializing SCI3.
Start
Sets bits SPC31 and
SPC32 to 1 in SPCR
1. Read the serial status register (SSR) and
Read bit TDRE
check that bit TDRE is set to 1, then write
transmit data to the transmit data register
1
in SSR
(TDR). When data is written to TDR, bit
TDRE is cleared to 0 automatically, the
clock is output, and data transmission is
No
started. When clock output is selected,
the clock is output and data transmission
started when data is written to TDR.
TDRE = 1?
Yes
2. When continuing data transmission, be
sure to read TDRE = 1 to confirm that
a write can be performed before writing
data to TDR. When data is written to
TDR, bit TDRE is cleared to 0 automatically.
Write transmit
data to TDR
Yes
Continue data
transmission?
2
No
Read bit TEND
in SSR
No
TEND = 1?
Yes
Clear bit TE to 0
in SCR3
End
Figure 10-16 Example of Data Transmission Flowchart (Synchronous Mode)
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ETC [ ETC ]
