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STD130
5-24
Samsung ASIC
SPSRAMBW_HD
High-Density Single-Port Synchronous Static RAM with Bit-Write
Logic Symbol
Function Description
SPSRAMBW_HD is a single-port synchronous static RAM with bit-write capability which is provided as a
compiler. SPSRAMBW_HD is intended for use in high-density applications. Basically, its functionality is
exactly same as SPSRAM_HD except a bit-write operation which is controlled by BWEN[], named bit-write
enable signal bus. Each bit of BWEN[] enables or disables the write operation of its corresponding bit in DI[].
On the rising edge of CK, the write cycle is initiated when WEN is low and CSN is low. The data bits in DI[],
which their corresponding bit(s) in BWEN[] are low, are written into the memory location specified on A[].
When all bits of BWEN[] are high, any data in DI[] are not written into the memory location specified on A[].
When all bits of BWEN[] are low, the data in DI[] are written into the memory location specified on A[], which
is exactly same as the write operation in SPSRAM_HD. During the write cycle, DOUT[] remains stable. On
the rising edge of CK, the read cycle is initiated when WEN is high and CSN is low. The data at DOUT[]
become valid after a delay. While in standby mode that CSN is high, A[] and DI[] are disabled, data stored in
the memory is retained and DOUT[] remains stable. When OEN is high, DOUT[] is placed in a
high-impedance state.
SPSRAMBW_HD Function Table
CK
CSN
WEN
OEN
A
BWEN
DI
DOUT
Comment
X
X
X
H
X
X
X
Z
Unconditional tri-state output
X
H
X
L
X
X
X
DOUT(t-1)
De-selected (standby mode)
↑
↑
↑
↑
L
L
L
Valid
all L
Valid
DOUT(t-1)
Word-write cycle
L
L
L
Valid
L
Valid
DOUT(t-1)
Bit-write cycle
L
L
L
Valid
all H
Valid
DOUT(t-1)
No operation
L
H
L
Valid
X
X
MEM(A)
Read cycle
Features
Suitable for high-density application
Bit-Write capability
Separated data I/O
Synchronous operation
Duty-free clock cycle
Asynchronous tristate output
Latched inputs and outputs
Automatic power-down
Zero standby current
Zero hold time
Low noise output optimization
Flexible aspect ratio
Dual-bank scheme available
Up to 512K bits capacity
Up to 32K number of words
Up to128 number of bit per word
CK
CSN
WEN
BWEN [b-1:0]
OEN
A [m-1:0]
spsrambw_hd_<w>x<b>m<y>b<ba>
DOUT [b-1:0]
NOTES:
1. Words(w) is the number of words.
2. Bpw(b) is the number of bits per word.
3. Ymux(y) is one of the column mux types.
4. Banks(ba) is the number of banks.
5. m =
log
2
w
DI [b-1:0]