at94k10al ATMEL Corporation, at94k10al Datasheet - Page 173

• Manufacturer Part Number: at94k10al
• Description: At94k05al 5k - 40k Gates Of At40k Fpga With 8-bit Microcontroller, Up To 36k Bytes Of Sram And On-chip Jtag Ice
• Manufacturer: ATMEL Corporation

6.1
1138I–FPSLI–1/08
FPSLIC Dual-port SRAM Characteristics
The Dual-port SRAM operates in single-edge clock controlled mode during read operations, and
a double-edge controlled mode during write operations. Addresses are clocked internally on the
rising edge of the clock signal (ME). Any change of address without a rising edge of ME is not
considered.
In read mode, the rising clock edge triggers data read without any significant constraint on the
length of the clock pulse. The WE signal must be changed and held Low before the rising edge
of ME to signify a read cycle. The WE signal should then remain Low until the falling edge of the
clock.
In write mode, data applied to the inputs is latched on either the falling edge of WE or the falling
edge of the clock, whichever comes earlier, and written to memory. Also, WE must be High
before the rising edge of ME to signify a write cycle. If data inputs change during a write cycle,
only the value present at the write cycle end is considered and written to the address clocked at
the ME rise. A write cycle ending on WE fall does not turn into a read cycle – the next cycle will
be a read cycle if WE remains Low during rising edge of ME.
Figure 6-1.
Figure 6-2.
DATA READ
CLK (ME)
ADDR
DATA WRITE
WE
CLK (ME)
ADDR
WE
SRAM Read Cycle Timing Diagram
SRAM Write Cycle Timing Diagram
t
Previous Data
ADS
t
Address Valid
RDS
t
ADS
t
Address Valid
WRS
t
ADH
t
ACC
t
ADH
t
MEH
t
MPW
t
MPW
t
WDS
t
WDS
Data Valid
Output Valid
AT94KAL Series FPSLIC
t
t
t
RDH
MEL
WDH
t
WDH
t
t
t
t
t
t
t
ADS
ADH
RDS
RDH
ACC
MEH
MEL
t
t
t
t
t
t
ADS
ADH
WRS
MPW
WDS
WDH
- Address Setup
- Address Hold
- Read Cycle Setup
- Read Cycle Hold
- Access Time from posedge ME
- Minimum ME High
- Minimum ME Low
- Address Setup
- Address Hold
- Write Cycle Setup
- Minimum Write Duration
- Data Setup to Write End
- Data Hold to Write End
173