PT7A6632J PERICOM [Pericom Semiconductor Corporation], PT7A6632J Datasheet - Page 24

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

•
The first 8 bytes in the transmit Data Buffer is Descriptors that
specifies Next Buffer Address, Buffer Size, Data Length and
Status respectively. See Table 6 for the definition.
•
Following the Descriptors are the data to be transmitted. The
number of bytes are specified by Data Length (for complete
PT019(05/02)
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Data Processing Memory
General
The Data Processing Memory refers to Data or Command buff-
ers which are linked each other. The PT7A6632 accesses the
Data Processing Memory for transmit/receive data and opera-
tion commands. Each buffer has following configuration (see
Figure 22):
Figure 23. Transmit Data Buffer
(i+7)+j+1
Descriptors
Data Bytes
•
•
(Address)
(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
8-Byte Descriptors
Data bytes to be transmitted or received or Command
i
~ ~
~ ~
msb
UNDR IVBA
FC
7
Not used
FO
Last Location in Buffer
Not Used by PT7A6632
Flag Count (Optional)
Second Date Byte
Not used
a. MDFS = 1
Last Date Byte
First Date Byte
Not used
(Contents)
msb
msb
CF/P
-
CMND
(0)
MPTY
lsb
lsb
lsb
0
~ ~
~ ~
Status
Next Buffer
Address
Buffer
Size (k)
Data
Length (j)
24
PT7A6632 32-Channel HDLC Controller
There are 4 kinds of buffers, Transmit Data Buffer and Trans-
mit Command Buffer for transmit channels, and Receive Data
Buffer and Receive Command Buffer for receive channels.
Transmit Data Buffer
The Transmit Data Buffer contains 8 bytes of descriptors and j
bytes of user’s data as shown in Figure 23. The MDFS pin
decides the most significant byte and least significant byte
locations (in even and odd addresses).
data buffer) or Buffer Size (for partial data buffer). The buffer
may contains last byte of a frame (CF/P = 1) or partial data of a
frame (CF/P = 0) in HDLC mode. The CF/P should be reset for
other modes.
•
Specifies the additional flags to be added after “CRC + one
Flag” of a frame. It will be read only when Flag Control bit in
the MS byte of Data Length is set (FC = 1).
(Address)
(i+7)+j+1
(i+7)+1
(i+7)+2
(i+7)+k
Flag Count Byte (Optional)
(i+7)+j
i+1
i+2
i+3
i+4
i+5
i+6
i+7
i
~ ~
~ ~
msb
UNDR IVBA
FC
7
Not used
FO
Last Location in Buffer
Not Used by PT7A6632
Flag Count (Optional)
Second Date Byte
Not used
b. MDFS = 0
Last Date Byte
First Date Byte
Not used
(Contents)
msb
msb
CF/P
-
CMND
(0)
MPTY
Data Sheet
lsb
lsb
lsb
0
~ ~
~ ~
Status
Next Buffer
Address
Buffer
Size (k)
Data
Length (j)
Ver:2