Contec BX220 Series - Page 84

6. Appendix
BX-220 User’s manual
75
Table 6.3. Function of Each Register < 3 / 4 >
MCR: Modem Control Regis
t
e
r
D
7 D
6 D
5
D4
D
3 D
2 D
1
D0
03FCH
I/O address
D
e
s
c
r
i
p
t
i
o
n
0
:
In
ac
t
iv
e
[H
I
GH
]
1
:
A
ct
iv
e
[L
O
W]
0 0
0 L
oo
p
IR
Q X
R
TS
DT
R
DT
R
RT
S
0
:
I
na
c
ti
ve
[
HI
G
H]
1
:
A
c
ti
ve
[
LO
W
]
Interrupt con
t
ro
l
b
it
0 : Disable
1
: Enable
D
ia
g
no
s
ti
c
l
ocal loop-back tes
t
0
:
Di
s
ab
l
e
1
:
En
ab
l
e
LSR: Line
S
t
at
us
Re
g
es
te
r
03
FDH
D7 D6 D
5
D4
D3
D
2 D
1
D0
0
TEMT
THRE
BI
F
E P
E O
E
DR
Da
t
a
r
ea
dy
(
1
fo
r
e
xi
s
te
n
ce
o
f received data)
Ov
er
r
un
e
r
ro
r
(
1
f
o
r
oc
c
ur
re
n
ce
o
f
a
n
e
rr
o
r)
Pari
ty
er
ro
r
(
1
f
or
oc
cu
r
re
nc
e
o
f
a
n
e
rr
or)
Framing error (
1
f
or
o
c
cu
rr
e
nc
e
o
f
a
n
er
r
or
)
Break interrupt (1 for detect
i
on
o
f
b
re
a
k
s
ta
te
)
T
ran
smi
tter
ho
ldi
ng
regis
ter
em
pty
(
1 f
or
tran
smi
ssi
on b
uff
er b
ein
g em
pty
)
Tr
ansmi
tte
r em
pty
(Se
t t
o 1 whe
n b
oth
tra
nsm
itt
er
hold
ing reg
ist
er
and
tra
nsm
itter shi
ft
reg
ist
er a
re
emp
ty.)