XRT86VL38
PRELIMINARY
xr
OCTAL T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.6
47
ACK0
ACK1
Y23
Y24
W22
V21
I
DMA Cycle Acknowledge Input—DMA Controller 0 (Write):
The external DMA Controller will assert this input pin “Low” when
the following two conditions are met:
1.
After the DMA Controller, within the Framer has asserted
(toggled “Low”), the Req_0 output signal.
2.
When the external DMA Controller is ready to transfer data
from external memory to the selected Transmit HDLC buffer.
At this point, the DMA transfer between the external memory and
the selected Transmit HDLC buffer may begin.
After completion of the DMA cycle, the external DMA Controller will
negate this input pin after the DMA Controller within the Framer has
negated the Req_0 output pin. The external DMA Controller must do
this in order to acknowledge the end of the DMA cycle.
DMA Cycle Acknowledge Input—DMA Controller 1 (Read):
The external DMA Controller asserts this input pin “Low” when the
following two conditions are met:
1.
After the DMA Controller, within the Framer has asserted
(toggled "Low"), the Req_1 output signal.
2.
When the external DMA Controller is ready to transfer data
from the selected Receive HDLC buffer to external memory.
At this point, the DMA transfer between the selected Receive HDLC
buffer and the external memory may begin.
After completion of the DMA cycle, the external DMA Controller will
negate this input pin after the DMA Controller within the Framer has
negated the Req_1 output pin. The external DMA Controller will do
this in order to acknowledge the end of the DMA cycle.
N
OTE
: This pin is internally pulled “High” with a 50k
Ω
resistor.
BLAST
P23
M17
I
Last Cycle of Burst Indicator Input:
If the Microprocessor Interface is operating in the Intel-I960 Mode,
then this input pin is used to indicate (to the Microprocessor Inter-
face block) that the current data transfer is the last data transfer
within the current burst operation.
The Microprocessor should assert this input pin (by toggling it “Low”)
in order to denote that the current READ or WRITE operation (within
a BURST operation) is the last operation of this BURST operation.
N
OTES
:
1.
If the user has configured the Microprocessor Interface to
operate in the Intel-Asynchronous, the Motorola-
Asynchronous or the Power PC 403 Mode, then he/she
should tie this input pin to GND.
2.
This pin is internally pulled “High” with a 50k
Ω
resistor.
RESET
Y4
Y1
I
Hardware Reset Input
Reset is an active low input. If this pin is pulled “Low” for more than
10
µ
S, the device will be reset. When this occurs, all output will be
‘tri-stated’, and all internal registers will be reset to their default val-
ues.
MICROPROCESSOR INTERFACE
S
IGNAL
N
AME
420 P
KG
B
ALL
#
484P
KG
B
ALL
#
T
YPE
D
ESCRIPTION