CY7C4255-10AC Cypress Semiconductor Corp, CY7C4255-10AC Datasheet - Page 16

• Manufacturer Part Number: CY7C4255-10AC
• Description: IC DEEP SYNC FIFO 8KX18 64LQFP
• Manufacturer: Cypress Semiconductor Corp
• Series: CY7Cr

Specifications of CY7C4255-10AC

• Function: Synchronous
• Memory Size: 144K (8K x 18)
• Data Rate: 100MHz
• Access Time: 8ns
• Voltage - Supply: 3.3V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Configuration: Dual
• Density: 144Kb
• Access Time (max): 8ns
• Word Size: 18b
• Organization: 8Kx18
• Sync/async: Synchronous
• Expandable: Yes
• Bus Direction: Uni-Directional
• Package Type: TQFP
• Clock Freq (max): 100MHz
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Supply Current: 45mA
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 64
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1230

Retransmit
The retransmit feature is beneficial when transferring packets of
data. It enables the receipt of data to be acknowledged by the
receiver and retransmitted if necessary.
The Retransmit (RT) input is active in the stand-alone and width
expansion modes. The retransmit feature is intended for use
when a number of writes equal to or less than the depth of the
FIFO have occurred and at least one word has been read since
the last RS cycle. A HIGH pulse on RT resets the internal read
Table 5. Flag Truth Table
Document #: 38-06004 Rev. *E
0
1 to n
(n + 1) to 4096
4097 to (8192 – (m + 1))
(8192 – m)
8192
Notes
38. n = Empty Offset (Default Values: CY7C4255/CY7C4265/65A n = 127).
39. m = Full Offset (Default Values: CY7C4255/CY7C4265/65A n = 127).
[38]
CY7C4255 – 8K x 18
[39]
to 8191
Number of Words in FIFO
0
1 to n
(n + 1) to 8192
8193 to (16384 – (m + 1))
(16384 – m)
16384
CY7C4265/65A – 16K x 18
[38]
[39]
to 16383
pointer to the first physical location of the FIFO. WCLK and
RCLK may be free running but must be disabled during and t
after the retransmit pulse. With every valid read cycle after
retransmit, previously accessed data is read and the read pointer
is incremented until it is equal to the write pointer. Flags are
governed by the relative locations of the read and write pointers
and are updated during a retransmit cycle. Data written to the
FIFO after activation of RT are transmitted also.
The full depth of the FIFO can be repeatedly retransmitted.
CY7C4255, CY7C4265, CY7C4265A
FF
H
H
H
H
H
L
PAF
H
H
H
H
L
L
HF
H
H
H
L
L
L
PAE
H
H
H
H
L
L
Page 16 of 23
EF
H
H
H
H
H
L
RTR
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