XRT86L30
REV. 1.0.1
SINGLE T1/E1/J1 FRAMER/LIU COMBO
TABLE 3: XRT86L30 MICROPROCESSOR
I
NTERFACE
S
IGNALS THAT EXHIBIT CONSTANT ROLES IN BOTH
ODES
INTEL AND
MOTOROLA
M
P
IN
N
AME
TYPE
DESCRIPTION
PTYPE[2:0]
I
Microprocessor Interface Mode Select Input pins
These three pins are used to specify the microprocessor interface mode. The relationship
between the state of these three input pins, and the corresponding microprocessor mode is
presented in Table 2
.
DATA[7:0]
I/O
I
Bi-Directional Data Bus for register "Read" or "Write" Operations.
ADDR[11:0]
15-Bit Address Bus Inputs
The XRT86L30 microprocessor interface uses a direct address bus. This address bus is pro-
vided to permit the user to select an on-chip register for Read/Write access.
CS
I
Chip Select Input
This active low signal selects the microprocessor interface of the XRT86L30 and enables
Read/Write operations with the on-chip register locations.
TABLE 4: INTEL MODE: MICROPROCESSOR INTERFACE SIGNALS
I
NTEL
QUIVALENT
IN
XRT86L30
TYPE
DESCRIPTION
E
P
IN NAME
P
ALE
RD
ALE
I
I
Address-Latch Enable: This active high signal is used to latch the contents on
the address bus ADDR[11:0]. The contents of the address bus are latched into
the ADDR[11:0] inputs on the falling edge of ALE.
RD
Read Signal: This active low input functions as the read signal from the local
µ
P.
When this pin is pulled “Low” (if CS is “Low”) the XRT86L30 is informed that a
read operation has been requested and begins the process of the read cycle.
WR
RDY
WR
RDY
I
Write Signal: This active low input functions as the write signal from the local
When this pin is pulled “Low” (if CS is “Low”) the XRT86L30 is informed that a
write operation has been requested and begins the process of the write cycle.
µ
P.
O
Ready Output: This active low signal is provided by the XRT86L30 device. It
indicates that the current read or write cycle is complete, and the XRT86L30 is
waiting for the next command.
22
EXAR [ EXAR CORPORATION ]
