CY7C4231V-25AC Cypress Semiconductor Corp, CY7C4231V-25AC Datasheet - Page 4
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CY7C4231V-25AC
Manufacturer Part Number
CY7C4231V-25AC
Description
Manufacturer
Cypress Semiconductor Corp
Datasheet
1.CY7C4231V-25AC.pdf
(18 pages)
Specifications of CY7C4231V-25AC
Configuration
Dual
Density
18Kb
Access Time (max)
15ns
Word Size
9b
Organization
2Kx9
Sync/async
Synchronous
Expandable
Yes
Bus Direction
Uni-Directional
Package Type
TQFP
Clock Freq (max)
40MHz
Operating Supply Voltage (typ)
3.3V
Operating Supply Voltage (min)
3V
Operating Supply Voltage (max)
3.6V
Supply Current
20mA
Operating Temp Range
0C to 70C
Operating Temperature Classification
Commercial
Mounting
Surface Mount
Pin Count
32
Lead Free Status / RoHS Status
Not Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
CY7C4231V-25AC
Manufacturer:
CYPRESS/赛普拉斯
Quantity:
20 000
Document #: 38-06010 Rev. *B
Programmable Flag (PAE, PAF) Operation
Whether the flag offset registers are programmed as
described in Table 1 or the default values are used, the
programmable Almost Empty Flag (PAE) and programmable
Almost Full Flag (PAF) states are determined by their corre-
sponding offset registers and the difference between the read
and write pointers.
Table 1. Writing the Offset Registers
Note:
1. The same selection sequence applies to reading from the registers. REN1 and REN2 are enabled and a read is performed on the LOW-to-HIGH transition of RCLK.
LD
0
0
1
1
8
8
8
8
WEN
64 x 9
0
1
0
1
6
6
Empty Offset (LSB) Reg.
Default Value = 007h
Full Offset (LSB) Reg
Default Value = 007h
WCLK
8
8
8
8
[1]
Empty Offset (LSB) Reg.
Default Value = 007h
Full Offset (LSB) Reg
Default Value = 007h
7
7
2K x 9
0
0
0
0
Empty Offset (LSB)
Empty Offset (MSB)
Full Offset (LSB)
Full Offset (MSB)
No Operation
Write Into FIFO
No Operation
2
2
(MSB)
(MSB)
000
000
8
8
8
8
Figure 1. Offset Register Location and Default Values
256 x 9
Selection
Empty Offset (LSB) Reg.
Default Value = 007h
7
7
Full Offset (LSB) Reg
Default Value = 007h
0
0
0
0
8
8
8
8
Empty Offset (LSB) Reg.
Default Value = 007h
Full Offset (LSB) Reg
Default Value = 007h
7
7
0
0
0
0
4K x 9
3
3
(MSB)
(MSB)
0000
0000
8
8
8
8
The number formed by the empty offset least significant bit
register and empty offset most significant register is referred
to as n and determines the operation of PAE. PAE is synchro-
nized to the LOW-to-HIGH transition of RCLK by one flip-flop
and is LOW when the FIFO contains n or fewer unread words.
PAE is set HIGH by the LOW-to-HIGH transition of RCLK
when the FIFO contains (n+1) or greater unread words.
The number formed by the full offset least significant bit
register and full offset most significant bit register is referred to
as m and determines the operation of PAF. PAE is synchro-
nized to the LOW-to-HIGH transition of WCLK by one flip-flop
and is set LOW when the number of unread words in the FIFO
is greater than or equal to CY7C4421V (64 – m), CY7C4201V
(256 – m), CY7C4211V (512 – m), CY7C4221V (1K – m),
CY7C4231V (2K – m), CY7C4241V (4K – m), and
CY7C4251V (8K – m). PAF is set HIGH by the LOW-to-HIGH
transition of WCLK when the number of available memory
locations is greater than m.
512 x 9
Empty Offset (LSB) Reg.
Default Value = 007h
Full Offset (LSB) Reg
Default Value = 007h
7
7
CY7C4421V/4201V/4211V/4221V
0
0
0
0
8
8
8
8
CY7C4231V/4241V/4251V
(MSB)
(MSB)
0
0
0
0
0
0
Empty Offset (LSB) Reg.
Default Value = 007h
Full Offset (LSB) Reg
Default Value = 007h
7
7
8K x 9
4
4
8
8
8
8
(MSB)
(MSB)
00000
00000
Empty Offset (LSB) Reg.
Default Value = 007h
Full Offset (LSB) Reg
Default Value = 007h
1K x 9
7
7
0
0
0
0
1
1
(MSB)
(MSB)
00
00
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