PT7A6632J PERICOM [Pericom Semiconductor Corporation], PT7A6632J Datasheet - Page 31

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

PT019(05/02)
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Receive Data Buffer
The Receive Data Buffer contains 8 bytes of descriptors and j
bytes of user’s data as shown in Figure 26. The MDFS pin
decides the MS byte and LS byte locations (in even and odd
addresses).
•
The first 8 bytes in the Receive Data Buffer are Descriptors
that specify Next Buffer Address, Buffer Size, Data Length and
Status respectively. See Table 11 for the definition.
Figure 26. Receive Data Buffer
(Address)
Descriptors
(i+7)+1
(i+7)+2
(i+7)+k
(i+7)+j
i+1
i+2
i+3
i+4
i+5
i+6
i+7
i
~ ~
~ ~
msb
OVER IVBA ABRT FCER SHER CF/P
7
Not used
Not used
Last Location in Buffer
Not Used by PT7A6632
Second Date Byte
a. MDFS = 1
Last Date Byte
First Date Byte
(Contents)
msb
msb
-
CMND
(0)
MPTY
lsb
lsb
lsb
0
~ ~
~ ~
Status
Next Buffer
Address
Buffer
Size (k)
Data
Length (j)
31
PT7A6632 32-Channel HDLC Controller
•
Following the Descriptors are received data. The number of
data bytes are indicated by Data Length which is written by
the PT7A6632 after it receives the last byte of an HDLC frame
or the HDLC ABORT code, upon the loss of multiframe align-
ment error from a non-HDLC signaling channel, or when Re-
ceiver Bit-Level Processor detects receive synchronization
error caused by RSYN, elastic buffer error or RRED. When it is
a partial data buffer, the number of data bytes is indicated by
the Buffer Size.
(Address)
(i+7)+1
(i+7)+2
(i+7)+k
(i+7)+j
Data Bytes
i+1
i+2
i+3
i+4
i+5
i+6
i+7
i
~ ~
~ ~
msb
OVER IVBA ABRT FCER SHER CF/P
7
Not used
Not used
Last Location in Buffer
Not Used by PT7A6632
Second Date Byte
b. MDFS = 0
Last Date Byte
First Date Byte
(Contents)
msb
msb
-
CMND
(0)
MPTY
lsb
Data Sheet
lsb
lsb
0
~ ~
~ ~
Status
Next Buffer
Address
Buffer
Size (k)
Data
Length (j)
Ver:2