IDT72T72115 Integrated Device Technology, IDT72T72115 Datasheet - Page 20

• Manufacturer Part Number: IDT72T72115
• Description: 128k X 72 Terasync Fifo, 2.5v - Best Value!
• Manufacturer: Integrated Device Technology

MARK is HIGH), a retransmit can be initiated by a rising RCLK edge while the
retransmit input (RT) is LOW. REN must be HIGH (reads disabled) before
bringing RT LOW. The device indicates the start of retransmit setup by setting
OR HIGH.
RCLK edge after retransmit setup is complete, (RT goes HIGH), the contents
of the first retransmit location are loaded onto the output register. Since FWFT
mode is selected, the first word appears on the outputs regardless of REN, a
LOW on REN is not required for the first word. Reading all subsequent words
requires a LOW on REN to enable the rising RCLK edge. See Figure 19,
Retransmit from Mark timing (FWFT mode), for the relevant timing diagram.
TABLE 5 — I/O CONFIGURATION
IDT72T7285/72T7295/72T72105/72T72115 2.5V TeraSync™ ™ ™ ™ ™ 72-BIT FIFO
16,384 x 72, 32,768 x 72, 65,536 x 72, 131,072 x 72
WHSTL: HIGH = HSTL
Once a marked location has been set (and the device is still in retransmit mode,
When OR goes LOW, retransmit setup is complete and on the next rising
Note, there must be a minimum of 32 bytes of data between the write pointer
Dn (I/P)
WCLK/WR (I/P)
WEN (I/P)
WCS (I/P)
WHSTL SELECT
LOW = LVTTL
RCLK/RD (I/P)
RCS (I/P)
MARK (I/P)
REN (I/P)
OE (I/P)
RT (I/P)
Qn (O/P)
RHSTL: HIGH = HSTL
RHSTL SELECT
LOW = LVTTL
EF/OR (O/P)
PAF (O/P)
EREN (O/P)
PAE (O/P)
FF/IR (O/P)
HF (O/P)
ERCLK (O/P)
TDO (O/P)
20
SCLK (I/P)
LD (I/P)
MRS (I/P)
TCK (I/P)
TMS (I/P)
SEN (I/P)
FWFT/SI (I/P)
and read pointer when the MARK is asserted. (32 bytes = 16 word = 8 long
words). Also, once the MARK is set, the write pointer will not increment past the
“marked” location until the MARK is deasserted. This prevents “overwriting” of
retransmit data.
HSTL/LVTTL I/O
I/O, via two select pins, WHSTL and RHSTL respectively. All other control pins
are selectable via SHSTL, see Table 5 for details of groupings.
the power consumption (in stand-by mode by utilizing the WCS input).
and are purely device configuration pins.
SHSTL: HIGH = HSTL
Both the write port and read port are user selectable between HSTL or LVTTL
Note, that when the write port is selected for HSTL mode, the user can reduce
All “Static Pins” must be tied to V
SHSTL SELECT
LOW = LVTTL
PRS (I/P)
TRST (I/P)
TDI (I/P)
CC
COMMERCIAL AND INDUSTRIAL
or GND. These pins are LVTTL only,
IW (I/P)
BM (I/P)
ASYR (I/P)
IP (I/P)
FSEL1 (I/P)
SHSTL (I/P)
RHSTL (I/P)
TEMPERATURE RANGES
STATIC PINS
LVTTL ONLY
OW (I/P)
ASYW (I/P)
BE (I/P)
FSEL0 (I/P)
PFM (I/P)
WHSTL (I/P)