INTV[7:0] — Interrupt Vector Number
The values of INTV[7:1] are the same for both QSPI and SCI interrupt requests; the
value of INTV0 used during an interrupt acknowledge cycle is supplied by the QSM.
INTV0 is at logic level zero during an SCI interrupt and at logic level one during a QSPI
interrupt. A write to INTV0 has no effect. Reads of INTV0 return a value of one.
D.4.4 SCCR0 — SCI Control Register 0
$YFFC08
15
0
14
0
13
0
12
0
SCBR
0
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
SCCR0 contains the SCI baud rate selection field. Baud rate must be set before the
SCI is enabled. The CPU32 can read and write SCCR0 at any time. Changing the val-
ue of SCCR0 bits during a transfer operation can disrupt operation.
SCBR — SCI Baud Rate
SCI baud rate is programmed by writing a 13-bit value to this field. Writing a value of
zero to SCBR disables the baud rate generator. Baud clock rate is calculated as fol-
lows:
D
$YFFC0A
D.4.5 SCCR1 — SCI Control Register 1
15
0
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
LOOPS
WOMS
ILT
PT
PE
M
WAKE
TIE
TCIE
RIE
ILIE
TE
RE
RWU
SBK
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
SCCR1 contains SCI configuration parameters, including transmitter and receiver en-
able bits, interrupt enable bits, and operating mode enable bits. The CPU can read and
write SCCR0 at any time. The SCI can modify the RWU bit under certain circumstanc-
es. Changing the value of SCCR1 bits during a transfer operation can disrupt opera-
tion.
LOOPS — Loop Mode
0 = Normal SCI operation, no looping, feedback path disabled
1 = Test SCI operation, looping, feedback path enabled
WOMS — Wired-OR Mode for SCI Pins
0 = If configured as an output, TXD is a normal CMOS output.
1 = If configured as an output, TXD is an open-drain output.
ILT — Idle-Line Detect Type
0 = Short idle-line detect (start count on first one)
1 = Long idle-line detect (start count on first one after stop bit(s))
MC68331
REGISTER SUMMARY
MOTOROLA
D-27
USER’S MANUAL
MOTOROLA [ MOTOROLA ]
