pt7a6527 Pericom Technology Inc, pt7a6527 Datasheet - Page 7

• Manufacturer Part Number: pt7a6527
• Description: Hdlc Controller
• Manufacturer: Pericom Technology Inc

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Interfaces
Microcontroller Interface
The PT7A6527 is programmable over an 8-bit parallel
microcontroller interface. Easy and fast microprocessor access
is provided by 8-bit address decoding on chip. The interface
consists of 13 (19) lines and is directly compatible with
processors of the multiplexed and demultiplexed address/data
bus types (Intel or Motorola processor families). The
microprocessor interface signals are summarized in table 6.
In addition to 8-bit processors, the PT7A6527 supports a
direct connection to 16-bit processors. Thus, through an
internal address transformation, it is possible to access all
PT7A6527 registers using either even microprocessor
addresses only or odd microprocessor addresses only.
Serial Interfaces
Depending on the selected mode, the PT7A6527 supports four
physically separate, full duplex serial interfaces, or one full
duplex serial interface.
In addition to the data input and data output lines, the serial
interface requires a common data clock (input DCL) and a
frame synchronization signal (input FSC). Input data is
latched on the falling edge of DCL and output data is clocked
off on the rising edge of DCL. The PT7A6527 may be
programmed so that the data clock rate is either equal to the
data rate, or twice the data rate.
Operating Modes
Each HDLC controller of the PT7A6527 is assigned to one
time channel determined either by time slot assignment or by
an external strobe signal.
Two basic configurations are distinguished (figure 4):
-
-
In the quad connection configuration two modes are
distinguished as follows:
-
-
Two modes are distinguished in turn for the single connection
configuration as follows:
PT0080(02/09)
In the quad connection configuration the four HDLC
controllers (A-D) are connected to individual time
multiplexed communication lines;
In the single connection configuration the four HDLC
channels are all connected to one time multiplexed
communication line.
Each connection is a time slotted highway, the lengths
and positions of the time slots are programmable (quad
connection time slot mode);
Each connection is a communication line, the time
channels are marked by an external strobe signal (quad
connection common control mode).
7
-
-
For simplicity, a time slotted highway will usually be referred
to as a PCM highway, or PCM for short.
Table 1 Four Basic Operation Modes of the PT7A6527
MDS1
To program the single connection IOM mode (CCR: MDS1,
MDS0 = 10)
with the slave mode
(MODE3-0:CMS1, CMS0 = 01) or
with the multi master mode
(MODE3-0:CMS1, CMS0 = 10) or
with the uncond. trans. mode
(MODE3- 0:CMS1, CMS0 = 00)
this additional programming has to be made:
MODE0:CCS1, CCS0 = 00 bin
MODE1:CCS1, CCS0 = 00 bin
MODE2:CCS1, CCS0 = 00 bin
MODE3:CCS1, CCS0 = 00 bin
TSR 0 = 0C hex
TSR1 = 1C hex
TSR2 = 2C hex
TSR3 = 3C hex
The four modes of operation are illustrated in figure 5. Via
channel-by-channel programming, one of a number of
collision detection modes may be selected in each of the basic
modes of operation. Refer to figure 5.
The four HDLC controllers of the PT7A6527 are connected to
the serial interfaces as shown in table 2. The table indicates
the selection of the data channel, the selectable time slot
widths, the output driver type, and the function of the active-
low Tri-State Control (TSC) output in each of the operating
modes.
The data output is set in a high impedance state outside the
time channel where data is transmitted.
OD = Open-drain driver,
PP = Push-pull driver.
The output driver type refers to the TXD0 (or TXD0, TXD1,
TXD2 and TXD3) outputs.
TSC is a push-pull signal.
0
0
1
1
The connection is a standard IOM interface with
predefined channel positions (single connection IOM
mode);
The connection is a time slotted highway (single
connection time slot mode).
MDS0
0
1
0
1
Single connection time slot mode
Quad connection common control mode
Single connection IOM mode
Quad connection time slot mode
Mode Description
HDLC controller
Data Sheet
PT7A6527
Ver:4