6.42
IDT70825S/L
High-Speed 8K x 16 Sequential Access Random Access Memory Industrial and Commercial Temperature Ranges
3
Pin Descriptions: Random Access Port(1)
Pin Descriptions: Sequential Access Port(1)
NOTE:
1. "I/O" is bidirectional input and output. "I" is input and "O" is output.
SYMBOL NAME I/O DESCRIPTIONS
A
0-
A
12
Address Line s I Ad dress inputs to acc ess the 8192-word (16-Bit) memory array.
I/O
0
-I/O
15
Inp uts/Outp uts I Rand o m ac ce ss d ata inp uts / o utp uts fo r 16-B it wid e d a ta.
CE Chip Enable I When CE is LOW, the random access port is enabled. When CE is HIGH, the random access port is disabled
into power-down mode and the I/O outputs are in the High-impedance state. All data is retained during CE =
V
IH
, unless it is altered by the sequential port. CE and CMD m ay not be L O W at the sam e ti me .
CMD Co ntro l Reg is te r
Enable I When CMD is LOW, add res s lines A
0
-A
2
, R/ W, and i n p uts / out p uts I/O
0
-I/O
12
, are use d to ac ce ss the control
register, the flag register, and the start and end of buffer registers. CMD and CE may not be LOW at the same
time.
R/WRead/ Wri te E na b l e I If CE is LOW and CMD is HIGH, d ata i s written i n to the array whe n R/ W is LOW and read o ut of the array when
R/W is HIGH. If CE i s HIGH and CMD is LOW, R/W is used to access the buffer command registers. CE and
CMD may not be LOW at the same time.
OE Outp ut Enable I When OE is LOW and R/ W is HIGH, I/O
0
-I/O
15
outp uts are enab le d . When OE is HIGH, th e I/ O o utputs are in
the High-impedance state.
LB, UB Lo we r By te , Up p e r
Byte Enables I W hen LB is LOW, I/O
0
-I/O
7
are ac ce ss ib le fo r read and write o pe ratio ns. Whe n LB is HIGH I/O
0
-I/O
7
are tri-
stated and blocked during read and write operations. UB c ontro ls acc ess fo r I/O
8
-I/O
15
in the same manne r and
is asynchronous from LB.
V
CC
Power Supply I Seven +5V powe r supply pins. All V
CC
pins must be co nnecte d to the same +5V V
CC
supply.
GND Gro und I Ten gro und p ins. All ground pins must be connecte d to the same ground sup ply.
3 016 tb l 01
SYMBOL NAME I/O DESCRIPTIONS
SI/O
0-15
Inp uts/Outp uts I S e q ue ntial d ata inp uts /o utp uts fo r 16-b it wid e d ata.
SCLK Clock I SI/O
0
-SI/O
15
, SCE, SR/W, and SLD are registered on the LOW-to-HIGH transition of SCLK. Also, the sequential
ac ces s p ort a d d re ss p oi nte r i nc re m e n ts b y 1 o n e a ch L OW -to -HIG H tr an s i ti o n o f S CLK wh e n CNTEN is LOW.
SCE Chip Enable I When SCE is LOW, the sequential access port is enabled on the LOW-to-HIGH transition of SCLK. When SCE
is HIGH, the sequential access port is disabled into powere d-down mode on the LOW-to-HIGH transition of
SCLK, and the SI/O outputs are in the High-impedance state. All data is retained, unless altered by the random
access port.
CNTEN Control Enable I When CNTEN is LOW, the address pointer increments on the LOW-to-HIGH transition of SCLK. This function is
independent of CE.
SR/WRe ad /Wri te E nab l e I Whe n S R/W and SCE are LOW, a write cycle is initiated on the LOW-to-HIGH transition of SCLK. When SR/ W is
HIGH, a nd SCE and SOE are LOW, a read c ycle is initiated o n the LOW-to-HIGH transitio n of SCLK. Termi nation
of a write cycle is d one on the LOW-to-HIGH trans ition of SCLK if SR/ W or SCE is HIGH.
SLD Address Pointer
Load Control IWhen SLD is sampled LOW, there is an internal delay of one cycle before the address pointer changes. When
SLD is LOW, data on the inputs SI/O
0
-SI/O
12
is lo ad e d into a da ta-i n r eg is ter o n the LOW-to -HIGH transitio n o f
SCLK. On the cycle following SLD, the address pointer changes to the address location contained in the data-
in register. SSTRT
1
and SSTRT
2
may not be LOW while SLD is LOW or during the cycle following SLD.
SSTRT
1
,
SSTRT
2
Load S tart of
Address Register IWhen SSTRT
1
or SSTRT
2
is LOW, the start of address register #1 or #2 is loaded into the address pointer on
the LOW-to-HIGH transition of SCLK. The start address are stored in internal registers. SSTRT
1
and SSTRT
2
may no t b e LOW whil e SLD is LOW or during the cycle following SLD.
EOB
1
,
EOB
2
End of Buffer Flag I EOB
1
or EOB
2
is output LOW when the address pointer is incremented to match the addre ss stored in the end
of the buffer registers. The flags can be cleared by either asserting RST LOW or by writing zero into Bit 0
and/or Bit 1 of the control register at address 101. EOB
1
and EOB
2
are dependent on separate internal
registers, and therefore separate match addresses.
SOE Output Enable I SOE controls the data outputs and is independent of SCLK. When SOE is LOW, o utput b uffe rs and the
sequentially addressed data is output. When SOE is HIGH, the SI/O output bus is in the High-impedance state.
SOE is asynchronous to SCLK.
RST Reset I When RST is LOW, all internal registers are set to their default state, the address pointer is set to zero and the
EOB
1
and EOB
2
flag s are se t HIG H. Rs t is as ync hr ono us to SCLK .
3016 tbl 02