PT7A6632J PERICOM [Pericom Semiconductor Corporation], PT7A6632J Datasheet - Page 30

• Manufacturer Part Number: PT7A6632J
• Description: PT7A6632 32-Channel HDLC Controller
• Manufacturer: PERICOM [Pericom Semiconductor Corporation]

•
The byte follows the FILL/MASK byte if any. It is used to
configure flexible hyperchannel. Bits 0 - 4 specify number of
a channel to be grouped into or removed from a hyperchannel.
Bits 6 and 7 is for hyperchannel enable and add/delete respec-
tively. See Table 10 for details.
Data Length is used to specify flexible hyperchannel. When
Data Length = 0, 1 or 2, only normal channel process. When
Data Length > 2, there is hyperchannel process.
•
The Flexible Hyperchannel mode allows the PT7A6632 to
group any number of 32 64kb/s channels into a hyperchannel.
The Data Length (>2) is read to decide the number of addi-
tional channels to be added to a hyperchannel. If a previously
activated channel is assigned to a flexible hyperchannel, it
will suspend the original buffer process, and the process will
be restored once the channel is released from the hyperchannel.
It may take one frame time. A channel can be assigned to one
hyperchannel only.
PT019(05/02)
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Figure 25. Minimum Data Bytes for Transmit Buffer
Table 10
B
B
B
B
B
t i
t i
t i
t i
t i
Flexible Hyperchannel Configuring Byte (Optional)
Flexible Hyperchannel
* Status Bits: CMND, MPTY, CF/P
Buffer
Next
7
7
7
7
7
0
1
1
Complete Data
Buffer (001)*
(
(
(
(
(
) E
) E
) E
) E
) E
3 Bytes
B
B
B
B
B
Partial Data Buffer
t i
t i
t i
t i
t i
Current Buffer
6
6
6
6
6
x
0
1
(
(
(
(
(
(000)*
A
A
A
A
A
)
)
)
)
)
H
n u
D
f
A
y h
o r
Buffer (000)*
y
e
d d
Partial Data
e p
h c
e l
m
e p
6 Bytes
e t
n a
c r
c
c r
y h
a h
a h
e g
a h
c
e p
a h
n n
n n
. d
n n
c r
n n
l e
D
D
D
D
D
. l e
l e
a h
l e
s e
s e
s e
s e
s e
u n
Current Buffer
s a
n n
r c
r c
r c
r c
r c
u n
m
i s
. l e
Next Buffer
p i
p i
p i
p i
p i
b
m
n g
r e
i t
i t
i t
i t
i t
b
m
Buffer
n o
n o
n o
n o
n o
r e
Complete Data
n i
Next
Buffer (001)*
e
t n
n i
b
2 Bytes
s t i
e r
b
s t i
Complete Data Buffer
m
0
4 -
i a
Current Buffer
0
Buffer (10x)*
s n
4 -
o t
Any Buffer
Command
(001)*
2 Bytes
(xxx)*
30
PT7A6632 32-Channel HDLC Controller
The channel map may be updated in one cycle of channel
counting. In flexible hyperchannel mode, the HCS0 and HCS1
should be set as “0 0”, otherwise the standard hyperchannel
will override the flexible hyperchannel.
•
If the CPU can not make next buffer ready before the PT7A6632
completes data transmission of a channel, the CPU will reset
the CF/P bit to indicate that it is a Partial Command Buffer
(CF/P=0, CMND=1). In this case the PT7A6632 will read Next
Buffer Address and send a HDLC flag(s) or a non-HDLC octet
all-ones to fill the gap, then the PT7A6632 turns to a new
buffer chain as if it complete a normal buffer process by setting
the MPTY and CF/P bits.
The PT7A6632 sends out flags or all-ones until it is informed
to resume data transmission by the CPU again. One Partial
Command Buffer sends one flag or one all-ones byte, a chain
of Partial Command Buffer sends multiple flags or ones. The
Partial Command Buffer processing will not change the MODE
and FILL/MASK.
If a Partial Command Buffer is processed after a partial data
buffer, the HDLC ABORT or non-HDLC all-ones will be sent.
Minimum Number of Data Bytes in a Tx Buffer
For Transmit Data Buffers and Transmit Command Buffers,
minimum number of data bytes is required for buffer mainte-
nance and buffer transition. The minimum numbers depend on
the current buffer type and next buffer type. Refer to Figure 25.
Buffer (000)*
Partial Command Buffer
Partial Data
5 Bytes
Min. Data Bytes
Buffer
Next
Complete Data
Buffer (001)*
2 Bytes
Command Buffer
Current Buffer
(10x)*
Data Sheet
Buffer (000)*
Partial Data
5 Bytes
Ver:2