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Samsung ASIC
5-157
STD150
DPSRAMBW_LP
Low-Power Dual-Port Synchronous Static RAM with Bit-Write
Logic Symbol
Function Description
DPSRAMBW_LP is a dual-port synchronous static RAM with bit-write capability which is provided as a
compiler. DPSRAMBW_LP is intended for use in low-power applications. Each port is fully independent.
Basically, its functionality is exactly same as DPSRAM_LP except a bit-write operation which is controlled by
BWEN1[](BWEN2[]), named bit-write enable signal bus. Each bit of BWEN1[](BWEN2[]) enables or disable
the write operation of its corresponding bit in DI1[](DI2[]). On the rising edge of CK1(CK2), the write cycle is
initiated when WEN1(WEN2) is low and CSN1(CSN2) is low. When the individual bit of BWEN1[](BWEN2[])
is low, the data on the corresponding write data bit of DI1[](DI2[]) are written into the memory location
specified on A1[](A2[]). When all bits of BWEN1[](BWEN2[]) are high, any data in DI1[](DI2[]) are not written
into the memory location specified on A1[](A2[]). When all bits of BWEN1[](BWEM2[]) are low, the data in
DI1[](DI2[]) are written into the memory location specified on A1[](A2[]), which is exactly same as the write
operation in DPSRAM_LP. During the write cycle, DOUT1[](DOUT2[]) remains stable. On the rising edge of
CK1(CK2), the read cycle is initiated when WEN1(WEN2) is high and CSN1(CSN2) is low. The data at
DOUT1[](DOUT2[]) become valid after a delay. While in standby mode that CSN1(CSN2) is high, A1[](A2[])
and DI1[](DI2[]) are disabled, data stored in the memory is retained and DOUT1[](DOUT2[]) remains stable.
When OEN1(OEN2) is high, DOUT1[](DOUT2[]) is placed in a high-impedance state.
DPSRAMBW_LP Function Table
CK1
CK2
X
X
↑
↑
↑
↑
CSN1
CSN2
X
H
L
L
L
L
WEN1
WEN2
X
X
L
L
L
H
OEN1
OEN2
H
L
L
L
L
L
A1
A2
X
X
Valid
Valid
Valid
Valid
BWEN1
BWEN2
X
X
All L
L
All H
X
DI1
DI2
X
X
Valid
Valid
Valid
X
DOUT1
DOUT2
Z
DOUT(t-1)
DOUT(t-1)
DOUT(t-1)
DOUT(t-1)
MEM(A)
Comment
Unconditional tri-state output
De-selected (standby mode)
Word-write cycle
Bit-write cycle
No operation
Read cycle
Features
Low-power application
Separated data I/O
Synchronous operation
Duty-free clock cycle
Asynchronous tri-state output control
Latched inputs and outputs
Automatic power-down
Near zero hold time
Low noise output optimization
Flexible aspect ratio
Up to 128Kbits capacity
Up to 8K number of words
Up to 128 number of bits per word
2. Bpw (b) is the number of bits per word.
3. Ymux (y) is one of the column mux types.
4. m =
log
2
w
CK1
CK2
CSN1
CSN2
WEN1
WEN2
BWEN1[b-1:0]
BWEN2[b-1:0]
dpsrambw_lp_<w>x<b>m<y>
DOUT1 [b-1:0]
OEN1
OEN2
A1 [m-1:0]
A2 [m-1:0]
DI1 [b-1:0]
DI2 [b-1:0]
DOUT2 [b-1:0]
NOTES:
1. Words (w) is the number of words.