at40kal ATMEL Corporation, at40kal Datasheet - Page 11

• Manufacturer Part Number: at40kal
• Description: At40kal Military Reprogrammable Fpgas With Freeram
• Manufacturer: ATMEL Corporation

RAM
4263B–AERO–06/03
32 x 4 dual-ported RAM blocks are dispersed throughout the array as shown in Figure 7.
A 4-bit Input Data Bus connects to four horizontal local buses distributed over four sec-
tor rows (plane 1). A 4-bit Output Data Bus connects to four horizontal local buses dis-
tributed over four sector rows (plane 2). A 5-bit Input Address Bus connects to five
vertical express buses in same column. A 5-bit Output Address Bus connects to five ver-
tical express buses in same column. Ain (input address) and Aout (output address)
alternate positions in horizontally aligned RAM blocks. For the left-most RAM blocks,
Aout is on the left and Ain is on the right. For the right-most RAM blocks, Ain is on the
left and Aout is tied off, thus it can only be configured as a single port. For single-ported
RAM, Ain is the READ/WRITE address port and Din is the (bi-directional) data port.
Right-most RAM blocks can be used only for single-ported memories. WEN and OEN
connect to the vertical express buses in the same column.
Figure 7. RAM Connections (One Ram Block)
Reading and writing of the 11 - 13 ns 32 x 4 dual-port FreeRAM are independent of
each other. Reading the 32 x 4 dual-port RAM is completely asynchronous. Latches are
transparent; when Load is logic 1, data flows through; when Load is logic 0, data is
latched. These latches are used to synchronize Write Adress, Write Enable Not, and Din
signals for a synchronous RAM. Each bit in the 32 x 4 dual-port RAM is also a transpar-
ent latch. The front-end latch and the memory latch together form an edge-triggered flip
flop. When a nibble (bit = 7) is (Write) addressed and LOAD is logic 1 and WE is logic 0,
AT40KAL
CLK
CLK
CLK
CLK
Ain
WEN
OEN
32 x 4 RAM
Din
CLK
Dout
Aout
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