Motorola MPC533 Reference Manual page 678

SCI Queue Operation
Transmit Queue Enabled
1
QTSZ=1111 (16 Data Frames)
QTPNT
0000
SCTQ[0]
SCTQ[7]
0111
SCTQ[8]
1000
SCTQ[15]
1111
QBHE Interrupt Received
3
(Wrap Occurred)
QTSZ=0000 (1 Data Frame)
QTPNT
0000
SCTQ[0]
0001
SCTQ[7]
0111
SCTQ[8]
1000
SCTQ[15]
1111
Load QPEND with QTSZ (0)
Clear QTWE
Reset QTPNT
Figure 15-36. Queue Transmit Example for 17 Data Bytes
15.8.7 Example SCI Transmit for 25 Data Bytes
Figure 15-37 below is an example of a transmission of 25 data frames.
15-72
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
QPEND
1111
1000
0111
0000
QPEND
0000
1111
MPC533 Reference Manual
QTHE Interrupt Received
2
QTSZ=1111 (16 Data Frames)
QTPNT
0000
SCTQ[0]
SCTQ[7]
0111
SCTQ[8]
1000
SCTQ[15]
1111
Write New QTSZ for When Wrap Occurs
QTSZ=0 (16+1=17),Set QTWE, Clear QTHE
Write SCTQ[0] for 17th Transfer
Data to be transferred
Available register space
QPEND
1111
1000
0111
0000
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