STDL130
5-86
Samsung ASIC
SPARAMBW_HDL
High-Density Single-Port Asynchronous Static RAM with Bit-Write
Logic Symbol
Function Description
SPARAMBW_HDL is a single-port synchronous static RAM with bit-write capability which is provided as a
compiler. SPARAMBW_HDL is intended for use in high-density applications. Basically, its functionality is
exactly same as SPARAM_HDL except a bit-write operation which is controlled by BWEN[], named bit-write
enable signal bus. Each bit of BWEN[] enables or disable the write operation of its corresponding bit in DI[].
At the falling edge of WEN, the write cycle is initiated when CSN is low. The data bytes or 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 SPARAM_HDL. At the rising edge of WEN, th write cycle is ended. The read
cycle is initiated when WEN is high and CSN is low. The data at DOUT[] become valid after a delay
whenever A[] transition is detected. 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.
SPARAMBW_HDL Function Table
CSN
X
H
L
L
L
L
L
L
L
WEN
X
X
↓
↓
↑
↑
L
L
H
OEN
H
L
L
L
L
L
L
L
L
A
X
X
BWEN
X
X
All L
L
All L
L
All L
L
X
DI
X
X
DOUT
Z
DOUT(t-1)
DOUT(t-1)
DOUT(t-1)
MEM(A)
MEM(A)
DOUT(t-1)
DOUT(t-1)
MEM(A)
Comment
Unconditional tri-state output
De-selected (standby mode)
Word-write cycle starts
Bit-write cycle starts
Word-write cycle ends and Read cycle starts
Bit-write cycle ends and Read cycle starts
Word-write cycle
Bit-write cycle
Read cycle
Valid
Valid
Valid
Valid
Stable
Stable
Toggle
Valid
Valid
Valid
Valid
Valid
Valid
X
Features
Suitable for high-density application
Bit-write capability
Separated data I/O
Asynchronous operation
Asynchronous tri-state output
Address transition detector
Write-enable transition detector
Chip-select transition detector
Bank-select transition detector
Automatic power-down mode available
Low noise output optimization
Zero standby current
Zero hold time for DI and BWEN
Flexible aspect ratio
Dual bank scheme available
Up to 512Kbits capacity
Up to 32K number of words
Up to 128 number of bit per word
CSN
WEN
BWEN [b-1:0]
OEN
A [m-1:0]
DI [b-1:0]
sparambw_hdl_<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