CY7C4261-25(2003) 데이터 시트보기 (PDF) - Cypress Semiconductor
부품명
상세내역
일치하는 목록
CY7C4261-25 Datasheet PDF : 18 Pages
| |||
CY7C4261
CY7C4271
Functional Description (continued)
The CY7C4261/71 provides four status pins: Empty, Full,
Programmable Almost Empty, and Programmable Almost Full.
The Almost Empty/Almost Full flags are programmable to
single word granularity. The programmable flags default to
Empty+7 and Full–7.
The flags are synchronous, i.e., they change state relative to
either the read clock (RCLK) or the write clock (WCLK). When
Pin Definitions
entering or exiting the Empty and Almost Empty states, the
flags are updated exclusively by the RCLK. The flags denoting
Almost Full, and Full states are updated exclusively by WCLK.
The synchronous flag architecture guarantees that the flags
maintain their status for at least one cycle.
All configurations are fabricated using an advanced 0.5µ
CMOS technology. Input ESD protection is greater than
2001V, and latch-up is prevented by the use of guard rings.
Signal Name Description
D0−8
Q0−8
WEN1
Data Inputs
Data Outputs
Write Enable 1
WEN2/LD
Write Enable 2
Dual Mode Pin Load
REN1, REN2
WCLK
Read Enable
Inputs
Write Clock
RCLK
Read Clock
EF
Empty Flag
FF
Full Flag
PAE
Programmable
Almost Empty
PAF
Programmable
Almost Full
RS
Reset
OE
Output Enable
I/O
Description
I Data Inputs for 9-bit bus.
O Data Outputs for 9-bit bus.
I The only write enable when device is configured to have programmable flags.
Data is written on a LOW-to-HIGH transition of WCLK when WEN1 is asserted and FF
is HIGH. If the FIFO is configured to have two write enables, data is written on a
LOW-to-HIGH transition of WCLK when WEN1 is LOW and WEN2/LD and FF are HIGH.
I If HIGH at reset, this pin operates as a second write enable. If LOW at reset, this
pin operates as a control to write or read the programmable flag offsets. WEN1 must be
LOW and WEN2 must be HIGH to write data into the FIFO. Data will not be written into
the FIFO if the FF is LOW. If the FIFO is configured to have programmable flags,
WEN2/LD is held LOW to write or read the programmable flag offsets.
I Enables the device for Read operation. Both REN1 and REN2 must be asserted to
allow a read operation.
I The rising edge clocks data into the FIFO when WEN1 is LOW and WEN2/LD is HIGH
and the FIFO is not Full. When LD is asserted, WCLK writes data into the programmable
flag-offset register.
I The rising edge clocks data out of the FIFO when REN1 and REN2 are LOW and
the FIFO is not Empty. When WEN2/LD is LOW, RCLK reads data out of the program-
mable flag-offset register.
O When EF is LOW, the FIFO is empty. EF is synchronized to RCLK.
O When FF is LOW, the FIFO is full. FF is synchronized to WCLK.
O When PAE is LOW, the FIFO is almost empty based on the almost empty offset
value programmed into the FIFO. PAE is synchronized to RCLK.
O When PAF is LOW, the FIFO is almost full based on the almost full offset value
programmed into the FIFO. PAF is synchronized to WCLK.
I Resets device to empty condition. A reset is required before an initial read or write
operation after power-up.
I When OE is LOW, the FIFO’s data outputs drive the bus to which they are connected. If
OE is HIGH, the FIFO’s outputs are in High Z (high-impedance) state.
Selection Guide
Maximum Frequency
Maximum Access Time
Minimum Cycle Time
Minimum Data or Enable Set-up
Minimum Data or Enable Hold
Maximum Flag Delay
Active Power Supply Commercial
Current (ICC1)
Industrial/
Military
7C4261/71-10
100
8
10
3
0.5
8
35
40
7C4261/71-15
66.7
10
15
4
1
10
35
40
7C4261/71-25
40
15
25
6
1
15
35
40
7C4261/71-35
28.6
20
35
7
2
20
35
40
Unit
MHz
ns
ns
ns
ns
ns
mA
Document #: 38-06015 Rev. *B
Page 2 of 18
Share Link: 