pt7a6525 Pericom Technology Inc, pt7a6525 Datasheet - Page 47

• Manufacturer Part Number: pt7a6525
• Description: Pt7a6525/6525l/6526 Hdlc Controller
• Manufacturer: Pericom Technology Inc

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Receive HDLC Control Register (Read) (RHCR)
The value of the HDLC control field corresponds to the last received frame.
Note: RHCR is duplicated in the RFIFO for every frame.
PT0017(12/05)
Table 24. Description of Receive HDLC Control Register
Note:
1. S frames are handled automatically and are not transferred to the microprocessor.
2. For U frames (bit 0 of RHCR = 1), the control field is as in the modulo 8 case.
3. For I frames (bit 0 of RHCR = 0), the compressed control field has the same format as in the
Table 25. Content of I frame in RHCR Register
D
D
modulo 8 case, but only the three LSBs of the receive and transmit counters are visible.
N
N
7
3
o
o
B t i
B t i
B t i
B t i
B
D
D
A
A
A
A
- n
- n
~
~
t i
4
0
u
u
u
u
u a
D
u a
D
o t
o t
o t
o t
U (
U (
U (
U (
T
5
1
T
o t
o t
m
m
m
m
a r
a r
d o
d o
d o
d o
m
m
f
f
f
f
s n
s n
a r
a r
a r
a r
d o
d o
, e
, e
, e
, e
a p
a p
m
m
m
m
M e d
M e d
M
M e d
M
, e
, e
e r
n o
e
n o
e
n o
e
n o
e
e r
o
o
o
) s
) s
) s
) s
o
o
t n
w t
t n
n o
- e
- e
- e
- e
e d
e d
N (
N (
N (
N (
y b
y b
y b
y b
- o
m
- e
m
o
o
o
o
y b
o
o
y b
e t
e t
e t
e t
N
N
N
N
N
e t
e t
e t
e t
e d
e d
( N
( N
e t
e t
a
a
a
a
a
a
a
a
a
P
0
) 1
) 1
) 1
) 1
m
m
m
m
m
d d
d d
d d
d d
) R
) S
1
0
a
a
e
e
e
e
e
d d
d d
e r
e r
e r
e r
s s
s s
s s
s s
e r
e r
s s
s s
T
-
-
T
e h
0
1
e h
T
T
u n
u n
e h
e h
M
M
M
M
M
m
m
e r
e r
b
b
o
o
o
o
o
e c
e c
r e
r e
u d
u d
u d
u d
u d
C
C
C
C
v i
v i
f o
f o
o l
o l
o l
o l
o l
n o
n o
n o
n o
d e
d e
r t
r t
r t
r t
8
8
8
8
8
a
a
l o
l o
l o
l o
f I
f I
a r t
e r
(
(
(
(
(
M
M
M
M
M
e c
47
a r
a r
e i f
e i f
e i f
e i f
PT7A6525/6525L/6526 HDLC Controller
s n
C
C
C
C
C
m
m
v i
d l
d l
d l
d l
m
S
S
S
S
S
e
e
d e
t t i
=
=
=
=
=
n
n
d e
e e
e e
f
) 0
) 0
) 0
) 0
) 0
a r
T
T
s d
s d
T
T
m
e h
e h
f
a r
e h
e h
C
C
C
C
C
e
o n
a
m
e s
e s
o
o
o
o
o
y b
r
i h t
i h t
t n
t n
t n
t n
t n
e
s e
o c
o c
r
s e
y b
n e
n e
n e
D
D
D
D
D
n e
n e
d r
d r
o p
R
d n
d n
o p
s e
s e
s e
s e
s e
e
s t
s t
s t
s t
s t
s n
y b
y b
R
m
r c
r c
r c
r c
r c
y b
y b
s n
e
. e
o
f o
f o
f o
f o
f o
C
C
e t
e t
m
-
p i
p i
p i
p i
p i
e t
. e
e t
e t
n o
n o
R
R
R
R
R
o
f a
f a
i t
i t
i t
i t
i t
S
f a
f a
e t
r t
r t
H
H
H
H
H
n o
n o
n o
n o
n o
r e t
r e t
a t
l o
l o
r e t
r e t
C
C
C
C
C
S
o i t
a t
l f
l f
R
R
R
R
R
e i f
e i f
M
M
M
M
M
l f
l f
. n
g a
g a
o i t
g a
g a
d l
d l
o
o
o
o
o
. n
u d
u d
u d
u d
u d
n i
n i
C
C
o l
o l
o l
o l
o l
o c
o c
n o
n o
N (
N (
1
1
1
1
1
m
m
r t
r t
8 2
8 2
8 2
8 2
8 2
o
o
l o
l o
p
p
e t
e t
e r
e r
(
(
(
(
(
M
M
M
M
M
e i f
e i f
) 2
) 2
s s
s s
Data Sheet
C
C
C
C
C
d e
d e
d l
d l
S
S
S
S
S
f
f
=
=
=
=
=
r o
r o
) 1
) 1
) 1
) 1
) 1
m
m
N (
N (
o
o
e t
e t
Ver:8
) 3
) 3