SERIAL COMMUNICATION INTERFACE (SCI)
MOTOROLA
PORT C
6 - 37
6.3.5
SCI Exceptions
The SCI can cause five different exceptions in the DSP (see Figure 6-53). These excep-
tions are as follows:
1. SCI Receive Data – caused by receive data register full with no receive error
conditions existing. This error-free interrupt may use a fast interrupt service
Baud Rate
(BPS)
SCP Bit
Divider Bits
(CD0–CD11)
Baud Rate
Error,
Percent
4.096M
0
$000
0
128K
0
$01F
0
64K
0
$03F
0
56K
0
$048
-0.195
32K
0
$07F
0
16K
0
$0FF
0
8000
0
$1FF
0
4000
0
$3FF
0
2000
0
$7FF
0
1000
0
$FFF
0
Table 6-4 (a) Synchronous SCI Bit Rates for a 32.768-MHz Crystal
BPS= f
0
÷
(8
×
(7(SCP) + 1)
×
(CD
+
1)); f
0
=32.768 MHz
SCP=0 or 1
CD=0 to $FFF
Bit Rate
(BPS)
SCP Bit
Divider Bits
(CD0–CD11)
Crystal
Frequency
2.048M
0
$001
32.768 MHz
1.544M
0
$002
37.056 MHz
1.536M
0
$002
36.864 MHz
Table 6-4 (b) Frequencies for Exact Synchronous SCI Bit Rates
f
0
=BPS
×
8
×
(7(SCP)
+
1)
×
(CD
+
1)
SCP=0 or 1
CD=0 to $FFF
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