PT7A6632 Datasheet, PDF (21/61 Pages) Pericom Semiconductor Corporation – PT7A6632 32-Channel HDLC Controller

Data Sheet
PT7A6632 32-Channel HDLC Controller
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Activation Memory
Channel Buffer Pointers
The Activation Memory map is shown in the Figure 21.
Channel Activation Byte
The Channel Activation Byte are illustrated in the following
table 5. The PT7A6632 reads this byte so that gets the channel
number, the channel state (active or inactive) and the channel
direction (transmit or receive). The PT7A6632 asserts SYSACC
when it accesses the Activation Memory.
Channel Buffer Pointers provide PT7A6632 the channel start-
ing address (16-bit) for each channel, 64 channels totally, guid-
ing to a link of buffers containing data and command. The
relative location of the upper and lower bytes of the 16-bit
start address word is determined by the MDFS input (see Fig-
ure 17). The upper address lines (A8-A15) are placed in the
high-impedance state or LOW by the PT7A6632 during the
Activation Memory accesses.
Table 5. Channel Activation Byte
Bit 7
Bit 6
Active bit
1
The channel
activated
0
The channel
deactivated
Unused
Bit 5
Rx/Tx bit
1
0
Receive
Transmit
Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Channel Number 0 ~ 31 (Binary)
0 0 0 0 0 - channel 0,
0 0 0 0 1 - channel 1,
0 0 0 1 0 - channel 2,
etc.
Figure 21a. Activation Memory Map Locations (MDFS = HIGH)
a. MDFS = HIGH (68000 Based)
(Address)
(HEX)
7
XX00 ^Active
XX01
XX7F
~~
XX80
XX81
XX82
XX83
(Contents)
6
5
4
3
2
1
x Rx/Tx
Channel Number
Byte Addresses xx01 Through
xx7F Are Not Used by PT7A6632
Transmit Channel 0 Start Address (High-Order Byte)
Transmit Channel 0 Start Address (Low-Order Byte)
Transmit Channel 1 Start Address (High-Order Byte)
Transmit Channel 1 Start Address (Low-Order Byte)
0
Channel Activation Byte
~~
~~
XXBE
XXBF
XXC0
XXC1
Transmit Channels 2 to 30 Start Addresses
Transmit Channel 31 Start Address (High-Order Byte)
Transmit Channel 31 Start Address (Low-Order Byte)
Receive Channel 0 Start Address (High-Order Byte)
Receive Channel 0 Start Address (Low-Order Byte)
~~
Channel Buffer Pointers
~~
Receive Channels 1 to 30 Start Address
~~
XXFE
Receive Channel 31 Start Address (High-Order Byte)
XXFF
Receive Channel 31 Start Address (Low-Order Byte)
PT019(05/02)
21
Ver:2