EP1S40B956C5 Altera, EP1S40B956C5 Datasheet - Page 393

• Manufacturer Part Number: EP1S40B956C5
• Description: IC STRATIX FPGA 40K LE 956-BGA
• Manufacturer: Altera
• Series: Stratix®r

Specifications of EP1S40B956C5

• Number Of Logic Elements/cells: 41250
• Number Of Labs/clbs: 4125
• Total Ram Bits: 3423744
• Number Of I /o: 683
• Voltage - Supply: 1.425 V ~ 1.575 V
• Mounting Type: Surface Mount
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 956-BGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Number Of Gates: -

Read-During-
Write Operation
at the Same
Address
Altera Corporation
July 2005
Power-up Conditions & Memory Initialization
Upon power-up, TriMatrix memory is in an idle state. The M512 and M4K
block outputs always power-up to zero, regardless of whether the output
registers are used or bypassed. Even if a memory initialization file is used
to pre-load the contents of the RAM block, the outputs still power-up
cleared. For example, if address 0 is pre-initialized to FF, the M512 and
M4K blocks power-up with the output at 00.
M-RAM blocks do not support memory initialization files; therefore, they
cannot be pre-loaded with data upon power-up. M-RAM blocks
combinatorial outputs and memory controls always power-up to an
unknown state. If M-RAM block outputs are registered, the registers
power-up cleared. The undefined output appears one clock cycle later.
The output remains undefined until a read operation is performed on an
address that has been written to.
The following two sections describe the functionality of the various RAM
configurations when reading from an address during a write operation at
that same address. There are two types of read-during-write operations:
same-port and mixed-port.
flow between same-port and mixed-port read-during-write.
Figure 2–14. Read-During-Write Data Flow
Same-Port Read-During-Write Mode
For read-during-write operation of a single-port RAM or the same port of
a true dual-port RAM, the new data is available on the rising edge of the
same clock cycle it was written on. This behavior is valid on all memory-
block sizes. See
TriMatrix Embedded Memory Blocks in Stratix & Stratix GX Devices
data out
data in
Port A
Port A
Figure 2–15
Figure 2–14
for a sample functional waveform.
data out
data in
Port B
Port B
Stratix Device Handbook, Volume 2
illustrates the difference in data
Mixed-port
Same-port
data flow
data flow
2–25