MPC555
/
MPC556
DEVELOPMENT SUPPORT
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
21-35
Figure 21-8 Asynchronous Clock Serial Communications
DSC
K
DSD
I
M
O
DE
CNTRL
D
I<0
>
S<
0>
S<1>
DO<0
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ST
AR
T
READ
Y
DSD
O
D
e
b
ug
P
o
rt
d
ri
v
e
s
“re
ad
y” b
it o
n
to
D
S
D
O
w
hen
rea
d
y
fo
r
a n
e
w
tr
ans
mi
ss
io
n.
D
e
b
ug
P
o
rt
de
tec
ts
the
“s
tar
t”
bit
on
D
S
D
I and
f
o
llo
w
s
the
“read
y”
bit
w
ith
tw
o s
tatu
s
b
its
an
d 7
or 3
2
o
u
tp
ut d
a
ta
bit
s
.
D
e
v
e
lo
pm
ent
T
o
o
l dr
iv
e
s
th
e “s
ta
rt
” bi
t on
D
S
D
I (a
fter
dete
c
ti
ng
“rea
d
y
” bi
t on
D
S
D
O
w
h
en
in d
e
b
u
g
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ode
). Th
e “s
tar
t” bit
is
im
m
edi
ate
ly
fo
llo
w
e
d
b
y
a m
ode
bi
t an
d a
co
ntro
l b
it a
nd
then
7
or 32
in
put
da
ta b
its
.
N
O
TE:
D
S
C
K
and
D
S
D
I tr
an
si
tio
n
s
are
not
req
u
ire
d
to
be
sy
nc
hro
nou
s w
ith C
L
K
O
U
T
.
DI
DI
DI <N
>
<N-1>
<N
-2
>
DO
D
O
DO <N
>
<N
-1
>
<N
-2
>
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
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I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
.
..