XRT72L52 Datasheet, PDF (31/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PRELIMINARY
PIN DESCRIPTION
PIN #
103
PIN NAME
A(9)
104
GND
105
D(0)
106
D(1)
107
D(2)
108
D(3)
109
VDD
110
D(4)
111
D(5)
112
D(6)
113
D(7)
114
GND
115
RDY_DTCK
116
INT
117
NC
XRT72L52
TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.3
TYPE
I
****
I/O
I/O
I/O
I/O
****
I/O
I/O
I/O
I/O
****
O
O
DESCRIPTION
Address Bus Input (Microprocessor Interface) - MSB (Most Signifi-
cant Bit):
This input pin, along with inputs A(0) - A(8) are used to select the on-
chip Framer register and RAM space for READ/WRITE operations with
the "local" microprocessor.
Ground
See Description for Pin 113
See Description for Pin 113
See Description for Pin 113
See Description for Pin 113
Power Supply 3.3V + 5%
See Description for Pin 113
See Description for Pin 113
See Description for Pin 113
MSB of Bi-Directional Data Bus (Microprocessor Interface Sec-
tion):
This pin, along with pins D(0) - D(6), function as the Microprocessor
Interface bi-directional data bus, and is intended to be interfaced to the
"local" microprocessor.
Ground
READY or DTACK:
This active-low output pin will function as the READY output, when the
microprocessor interface is running in the "Intel" Mode; and will function
as the DTACK output, when the microprocessor interface is running in
the "Motorola" Mode.
"Intel" Mode - READY Output:
When the Framer negates this output pin (e.g., toggles it "low"), it indi-
cates (to the µP) that the current READ or WRITE cycle is to be
extended until this signal is asserted (e.g., toggled "high").
"Motorola" Mode - DTACK (Data Transfer Acknowledge) Output:
The Framer device will assert this pin in order to inform the local micro-
processor that the present READ or WRITE cycle is nearly complete. If
the Framer device requires that the current READ or WRITE cycle be
extended, then the Framer will delay its assertion of this signal. The
68000 family of µPs requires this signal from its peripheral devices, in
order to quickly and properly complete a READ or WRITE cycle.
Interrupt Request Output:
This open-drain, active-low output signal will be asserted when the
Framer device is requesting interrupt service from the local micropro-
cessor. This output pin should typically be connected to the "Interrupt
Request" input of the local microprocessor.
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