
SEC ASIC
5-27
STD80/STDM80
SPSRAMA Gen
Single-Port Synchronous RAM Generator – Alternative
Logic Symbol
Function Description
SPSRAMA is a single-port synchronous static RAM. When WEN is high and CK rises, DOUT [ ] presents
data stored in the location addressed by A [ ]. When WEN is low and CK falls, or when CK is high and WEN
rises, the value of DI [ ] is written into the location addressed by A [ ]. CSN is used to enable/disable the
clock. OEN is used to enable/disable the data output driver.
SPSRAMA is an alternative of SPSRAM. The major difference of these two RAMs is the timing of read and
write. SPSRAMA reads and writes at different edge of the clock since SPSRAM reads and writes at the
same edge of the clock.
Generators and Cell Configurations
SPSRAMA Gen. generates layout, netlist, symbol and functional & timing model of SPSRAMA. The layout of
SPSRAMA is an automatically generated array of custom, pitch-matched leaf cells. To customize the
configuration of SPSRAMA, you can give certain values to following four generator parameters:
Number of words (w)
Number of bits per word (b)
Lower address decoder type (y)
Number of banks (ba).
The valid range of these parameters is specified in the following table:
Parameters
YMUX = 2
4
512
2
1
128
1
2
256
1
YMUX = 4
8
1024
4
1
64
1
2
128
1
YMUX = 8
16
2048
8
1
32
1
2
64
1
YMUX = 16
32
4096
16
1
16
1
2
32
1
YMUX = 32
64
8192
32
1
8
1
2
16
1
Words (w)
Min
Max
Step
Min
Max
Step
Min
Max
Step
Bpw (b)
ba = 1
ba = 2
CK
CSN
WEN
OEN
A [m:0]
DI [b–1:0]
spsrama<w>x<b>m<y>b<ba>
DOUT [b–1:0]
NOTES:
1. Words (w) is the number of words in SPSRAMA.
2. Bpw (b) is the number of bits per word.
3. Ymux (y) is one of the lower address decoder types.
4. Banks (ba) is the number of banks.
5. m =
log
2
w
– 1
Features
Synchronous operation
Read initiated at rising edge of clock
Write completed at falling edge of clock
Possible read modified write cycle
Stand-by (power down) mode available
Tri-state output
Separated data I/O
Low noise output circuit
Possible bi-directional operation
Flexible aspect ratio
Optional dual bank capacity
Up to 128K bits capacity
Up to 8K number of words
Up to 256 number of bits per word