IDT IDT70V631S10BC High-speed 3.3v 256k x 18 asynchronous dual-port static ram Datasheet

HIGH-SPEED 3.3V 256K x 18
ASYNCHRONOUS DUAL-PORT
STATIC RAM
IDT70V631S
Features
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True Dual-Port memory cells which allow simultaneous
access of the same memory location
High-speed access
– Commercial: 10/12/15ns (max.)
– Industrial: 12ns (max.)
Dual chip enables allow for depth expansion without
external logic
IDT70V631 easily expands data bus width to 36 bits or
more using the Master/Slave select when cascading more
than one device
M/S = VIH for BUSY output flag on Master,
M/S = VIL for BUSY input on Slave
Busy and Interrupt Flags
On-chip port arbitration logic
Full on-chip hardware support of semaphore signaling
between ports
Fully asynchronous operation from either port
Separate byte controls for multiplexed bus and bus
matching compatibility
Supports JTAG features compliant to IEEE 1149.1
– Due to limited pin count, JTAG is not supported on the
128-pin TQFP package.
LVTTL-compatible, single 3.3V (±150mV) power supply for
core
LVTTL-compatible, selectable 3.3V (±150mV)/2.5V (±100mV)
power supply for I/Os and control signals on each port
Available in a 128-pin Thin Quad Flatpack, 208-ball fine
pitch Ball Grid Array, and 256-ball Ball Grid Array
Industrial temperature range (–40°C to +85°C) is available
for selected speeds
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Functional Block Diagram
UBL
UBR
LBL
LBR
R/ WL
R/WR
B
E
0
L
CE0L
CE1L
B
E
1
L
B
E
1
R
B
E
0
R
CE0 R
CE1 R
OEL
OER
Dout0-8_L
Dout9-17_L
Dout0-8_R
Dout9-17_R
256K x 18
MEMORY
ARRAY
Din_L
I/O0L- I/O17L
A17L
A0L
Address
Decoder
Din_R
ADDR_L
OEL
CE0L
CE1L
I/O0R - I/O17R
ARBITRATION
INTERRUPT
SEMAPHORE
LOGIC
R/WL
A17R
Address
Decoder
ADDR_R
A0R
OER
CE0 R
CE1 R
R/WR
BUSYR
BUSYL
SEML
SEM R
M/S
INTL
INTR
TDI
TDO
JTAG
TMS
TCK
TRST
5622 drw 01
NOTES:
1. BUSY is an input as a Slave (M/S=VIL) and an output when it is a Master (M/S=VIH).
2. BUSY and INT are non-tri-state totem-pole outputs (push-pull).
OCTOBER 2003
1
©2003 Integrated Device Technology, Inc.
DSC-5622/5
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Description
The IDT70V631 is a high-speed 256K x 18 Asynchronous Dual-Port
Static RAM. The IDT70V631 is designed to be used as a stand-alone
4608K-bit Dual-Port RAM or as a combination MASTER/SLAVE DualPort RAM for 36-bit-or-more word system. Using the IDT MASTER/
SLAVE Dual-Port RAM approach in 36-bit or wider memory system
applications results in full-speed, error-free operation without the need for
additional discrete logic.
This device provides two independent ports with separate control,
address, and I/O pins that permit independent, asynchronous access for
reads or writes to any location in memory. An automatic power down
feature controlled by the chip enables (either CE0 or CE1) permit the
on-chip circuitry of each port to enter a very low standby power mode.
The 70V631 can support an operating voltage of either 3.3V or 2.5V
on one or both ports, controlled by the OPT pins. The power supply for
the core of the device (VDD) remains at 3.3V.
Pin Configurations(1,2,3,4)
09/30/03
1
2
3
4
5
6
7
8
9
10 11
12
13 14
15
16 17
A
I/O9L
NC
VSS
TDO
NC
A 16L
A12L
A8 L
NC
VDD
SEML
INTL
A4L
A0L
OPT L
NC
V SS
A
B
NC
VSS
NC
TDI
A17 L
A 13L
A 9L
NC
CE0L
VSS
BUSYL
A5L
A1L
VSS
VDDQR
I/O8L
NC
B
C
VDDQ L
I/O 9R
VDDQ R
VDD
NC
A1 4L
A10L
UBL
CE1L
VSS
R/WL
A6L
A2L
VDD
I/O8R
NC
VSS
C
D
NC
VSS
I/O10L
NC
A1 5L
A 11L
A7L
LBL
VDD
OE L
NC
A 3L
VDD
NC
VDDQ L
I/O 7L
I/O7R
D
E
I/O11L
NC
V DDQ R I/O 10R
I/O6L
NC
VSS
NC
E
F
VDDQ L
I/O 11R
NC
V SS
VSS
I/O 6R
NC
VDDQ R
F
G
NC
VSS
I/O1 2L
NC
NC
VDDQL
I/O5L
NC
G
H
VDD
NC
VDDQR
I/O 12R
VDD
NC
VSS
I/O5R
H
J
VDDQ L
V DD
VSS
VSS
VS S
VDD
VSS
VDDQ R
J
K
I/O14R
VSS
I/O13R
V SS
I/O3R
VDDQ L
I/O4R
VSS
K
L
NC
I/O 14L
V DDQ R
I/O 13L
NC
I/O 3L
VSS
I/O4 L
L
M
VDDQ L
NC
I/O15R
VSS
VSS
NC
I/O2R
VDDQR
M
N
NC
VSS
NC
I/O 15L
I/O1R
VDDQ L
NC
I/O 2L
N
P
I/O16R
I/O 16L
V DDQ R
NC
TRST
A 16R
A1 2R
A8 R
NC
VDD
SEMR
INT R
A4R
NC
I/O1L
VSS
NC
P
R
VSS
NC
I/O17R
TCK
A1 7R
A 13R
A9R
NC
CE0R
V SS
BUSYR
A5R
A 1R
VSS
VDDQL
I/O 0R
VDDQ R
R
T
NC
I/O17L
VDDQL
TMS
NC
A 14R
A10R
UBR
CE1R
V SS
R/WR
A6R
A 2R
VSS
NC
VSS
NC
T
U
VSS
NC
VDD
NC
A15R
A11R
A7R
LB R
VDD
OER
M/S
A3R
A 0R
V DD
OPTR
I/O0 L
U
70V631BF
BF-208(5)
208-Ball BGA
Top View(6)
NC
5622 tbl 02b
NOTES:
1. All VDD pins must be connected to 3.3V power supply.
2. All VDDQ pins must be connected to appropriate power supply: 3.3V if OPT pin for that port is set to VIH (3.3V) and 2.5V if OPT pin for that port is
set to VIL (0V).
3. All VSS pins must be connected to ground.
4. Package body is approximately 15mm x 15mm x 1.4mm with 0.8mm ball pitch.
5. This package code is used to reference the package diagram.
6. This text does not indicate orientation of the actual part-marking.
2
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
A14L
A15L
A16L
A17L
IO9L
IO 9R
VDDQL
VSS
IO10L
IO10R
VDDQR
VSS
IO11L
IO11R
IO12L
IO12R
VDD
VDD
VSS
VSS
IO13R
IO13L
IO14R
IO14L
IO15R
IO15L
VDDQL
VSS
IO16R
IO16L
VDDQR
VSS
IO17R
IO17L
A17R
A16R
A15R
A14R
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
70V631PRF
PK-128(5)
128-Pin TQFP
Top View(6)
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
09/30/03
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
A13L
A12L
A11L
A10L
A9L
A8L
A7L
UBL
LBL
CE1L
CE0L
VDD
VDD
VSS
VSS
SEML
OEL
R/WL
BUSYL
INTL
NC
A6L
A5L
A4L
A3L
A2L
Pin Configurations(1,2,3,4,7) (con't.)
A1L
A0L
OPTL
VSS
IO8L
IO8R
NC
VSS
VDDQL
IO7L
IO7R
VSS
VDDQR
IO6L
IO6R
IO5L
IO5R
VDD
VDD
VSS
VSS
IO4R
IO4L
IO3R
IO3L
IO2R
IO2L
VSS
VDDQL
IO1R
IO1L
VSS
VDDQR
IO0R
IO0L
OPTR
A0R
A1R
A13R
A12R
A11R
A10R
A9R
A8R
A7R
UBR
LBR
CE1R
CE0R
VDD
VDD
VSS
VSS
SEMR
OER
R/WR
BUSYR
INTR
M/S
A6R
A5R
A4R
A3R
A2R
.
5622 drw 02a
NOTES:
1. All VDD pins must be connected to 3.3V power supply.
2. All VDDQ pins must be connected to appropriate power supply: 3.3V if OPT pin for that port is set to VIH (3.3V) and 2.5V if OPT pin for that port is
set to VIL (0V).
3. All VSS pins must be connected to ground.
4. Package body is approximately 14mm x 20mm x 1.4mm.
5. This package code is used to reference the package diagram.
6. This text does not indicate orientation of the actual part-marking.
7. Due to the restricted number of pins, JTAG is not supported in the PK-128 package.
3
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Pin Configuration(1,2,3,4) (con't.)
70V631BC
BC-256(5)
256-Pin BGA
Top View(6)
09/30/03
A1
NC
B1
NC
C1
NC
D1
NC
E1
A2
TDI
B2
NC
C2
I/O9L
D2
I/O 9R
E2
I/O10R I/O10L
F1
I/O11L
G1
NC
H1
NC
J1
F2
NC
G2
NC
H2
I/O12R
J2
A3
NC
B3
TDO
C3
V SS
D3
NC
E3
NC
F3
A4
A5
A6
A17L
A 14L
A 11L
B4
NC
C4
A16L
D4
V DD
E4
V DDQL
F4
I/O11R VDDQL
G3
G4
I/O12L VDDQR
H3
NC
J3
H4
VDDQR
J4
I/O 13L I/O14R I/O 13R V DDQL
K1
NC
L1
I/O 15L
M1
K2
NC
L2
NC
M2
I/O 16R I/O16L
N1
NC
P1
NC
R1
NC
T1
NC
N2
I/O17R
P2
K3
I/O14L V DDQL
L3
NC
T2
TCK
L4
I/O15R VDDQR
M3
NC
N3
NC
P3
I/O17L TMS
R2
K4
R3
TRST
T3
NC
M4
VDDQR
N4
VDD
P4
A16R
R4
NC
T4
A17R
B5
A15L
C5
A13L
D5
B6
A12L
C6
A10L
D6
A7
A 8L
B7
A 9L
C7
A7L
D7
A8
A9
NC
CE1L
B9
B8
A10
OEL
B10
CE0L R/WL
UBL
C8
C9
LBL
NC
D9
D8
C10
A11
INT L
B11
NC
C11
SEM L BUSYL
D10
D11
A12
A5L
B12
A4L
C12
A6L
D12
VDDQL VDDQL V DDQR VDDQR VDDQL VDDQL VDDQR VDDQR
E5
VDD
F5
VDD
G5
V SS
H5
VSS
J5
V SS
K5
V SS
L5
VDD
M5
VDD
N5
E6
VDD
F6
VSS
G6
VSS
H6
V SS
J6
VSS
K6
VSS
L6
VSS
M6
V DD
N6
E7
VSS
F7
VSS
G7
VSS
H7
VSS
J7
VSS
K7
VSS
L7
VSS
M7
VSS
N7
E8
E9
VSS
V SS
F9
F8
V SS
VSS
G9
G8
VSS
V SS
H8
H9
VSS
VSS
J8
J9
VSS
K8
V SS
K9
VSS
L8
V SS
L9
VSS
M8
V SS
M9
VSS
N8
V SS
N9
E10
VSS
F10
VSS
G10
VSS
H10
V SS
J10
VSS
K10
VSS
L10
V SS
M10
VSS
N10
E11
VDD
F11
VSS
G11
VSS
H11
VSS
J11
VSS
K11
VSS
L11
VSS
M11
VDD
N11
E12
A13R
R5
A15R
T5
A14R
P6
A10R
R6
A 12R
T6
A11R
P7
A7R
R7
A9R
T7
A8R
P8
P9
LBR
NC
R9
R8
UBR
T8
CE1R
P11
SEM R BUSYR
R10
CE0R R/W R
T9
NC
P10
T10
OER
R11
M/S
T11
INT R
A2L
B13
A1L
C13
A3L
D13
VDD
E13
VDD V DDQR
F12
VDD
G12
VSS
H12
VSS
J12
VSS
K12
VSS
L12
VDD
M12
VDD
N12
V DDQR VDDQR VDDQL VDDQL V DDQR V DDQR VDDQL V DDQL
P5
A13
P12
A6R
R12
A4R
T12
A 5R
F13
A14
A0L
B14
NC
C14
OPTL
D14
NC
E14
NC
F14
V DDQR I/O6R
G13
G14
VDDQL I/O5L
H13
V DDQL
J13
H14
NC
J14
A15
A16
NC
NC
B16
B15
NC
NC
C16
C15
I/O 8L
NC
D16
D15
NC
I/O 8R
E16
E15
I/O 7R
I/O7L
F15
F16
NC
G15
I/O 6L
G16
NC
NC
H16
H15
I/O5R
NC
J15
J16
V DDQR I/O 4R I/O 3R
K13
V DDQR
L13
K14
NC
L14
V DDQL I/O2L
M13
M14
V DDQL I/O1R
N13
VDD
P13
A3R
R13
A1R
T13
A2R
N14
NC
P14
NC
R14
OPTR
T14
A 0R
I/O 4L
K16
K15
NC
I/O 3L
L16
L15
NC
I/O2R
M16
M15
NC
I/O1L
N16
N15
NC
I/O 0R
P15
P16
NC
I/O0L
R16
R15
NC
T15
NC
,
T16
NC
NC
5622 drw 02c
NOTES:
1. All VDD pins must be connected to 3.3V power supply.
2. All VDDQ pins must be connected to appropriate power supply: 3.3V if OPT pin for that port is set to VIH (3.3V), and 2.5V if OPT pin for that port is
set to VIL (0V).
3. All VSS pins must be connected to ground supply.
4. Package body is approximately 17mm x 17mm x 1.4mm, with 1.0mm ball-pitch.
5. This package code is used to reference the package diagram.
6. This text does not indicate orientation of the actual part-marking.
4
,
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Pin Names
Left Port
Right Port
Names
CE0L, CE1L
CE0R, CE1R
Chip Enables
R/WL
R/WR
Read/Write Enable
OEL
OER
Output Enable
A0L - A17L
A0R - A17R
Address
I/O0L - I/O17L
I/O0R - I/O17R
Data Input/Output
SEML
SEMR
Semaphore Enable
INTL
INTR
Interrupt Flag
BUSYL
BUSYR
Busy Flag
UBL
UBR
Upper Byte Select
LBL
LBR
Lower Byte Select
VDDQL
VDDQR
Power (I/O Bus) (3.3V or 2.5V)(1)
OPTL
OPTR
Option for selecting VDDQX(1,2)
M/S
Master or Slave Select
VDD
Power (3.3V)(1)
VSS
Ground (0V)
TDI
Test Data Input
TDO
Test Data Output
TCK
Test Logic Clock (10MHz)
TMS
Test Mode Select
TRST
Reset (Initialize TAP Controller)
NOTES:
1. VDD, OPTX, and VDDQX must be set to appropriate operating levels prior to
applying inputs on I/OX.
2. OPTX selects the operating voltage levels for the I/Os and controls on that port.
If OPTX is set to VIH (3.3V), then that port's I/Os and controls will operate at 3.3V
levels and VDDQX must be supplied at 3.3V. If OPTX is set to VIL (0V), then that
port's I/Os and controls will operate at 2.5V levels and VDDQX must be supplied
at 2.5V. The OPT pins are independent of one another—both ports can operate
at 3.3V levels, both can operate at 2.5V levels, or either can operate at 3.3V
with the other at 2.5V.
5622 tbl 01
5
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Truth Table I—Read/Write and Enable Control(1)
OE
SEM
CE0
CE 1
UB
LB
R/W
Byte 1
I/O9-17
Byte 0
I/O0-8
X
H
H
X
X
X
X
High-Z
High-Z
Deselected–Power Down
X
H
X
L
X
X
X
High-Z
High-Z
Deselected–Power Down
X
H
L
H
H
H
X
High-Z
High-Z
Both Bytes Deselected
X
H
L
H
H
L
L
High-Z
DIN
Write to Byte 0 Only
X
H
L
H
L
H
L
DIN
High-Z
Write to Byte 1 Only
X
H
L
H
L
L
L
DIN
DIN
Write to Both Bytes
L
H
L
H
H
L
H
High-Z
DOUT
Read Byte 0 Only
L
H
L
H
L
H
H
DOUT
High-Z
Read Byte 1 Only
L
H
L
H
L
L
H
DOUT
DOUT
Read Both Bytes
H
H
L
H
L
L
X
High-Z
High-Z
Outputs Disabled
MODE
5622 tbl 02
NOTE:
1. "H" = VIH, "L" = VIL, "X" = Don't Care.
Truth Table II – Semaphore Read/Write Control(1)
Inputs(1)
Outputs
CE
R/W
OE
UB
LB
SEM
I/O1-17
I/O0
H
H
L
L
L
L
DATAOUT
DATAOUT
Read Data in Semaphore Flag (3)
H
↑
X
X
L
L
X
DATAIN
Write I/O0 into Semaphore Flag
L
X
X
X
X
L
______
______
Mode
Not Allowed
NOTE:
1. There are eight semaphore flags written to I/O0 and read from all the I/Os (I/O0-I/O17). These eight semaphore flags are addressed by A 0-A2.
2. CE = L occurs when CE0 = VIL and CE1 = VIH.
3. Each byte is controlled by the respective UB and LB. To read data UB and/or LB = VIL.
6
5622 tbl 03
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Recommended DC Operating
Conditions with VDDQ at 2.5V
Recommended Operating
Temperature and Supply Voltage(1)
GND
VDD
0 C to +70 C
0V
-40 C to +85 C
0V
Commercial
Industrial
Symbol
Ambient
Temperature
Grade
O
O
O
O
Industrial and Commercial Temperature Ranges
Parameter
VDD
Core Supply Voltage
3.3V + 150mV
VDDQ
I/O Supply Voltage
(3)
3.3V + 150mV
VSS
Ground
NOTE:
1. This is the parameter TA. This is the "instant on" case temperature.
5622 tbl 04
(3)
Min.
Typ.
Max.
Unit
3.15
3.3
3.45
V
2.4
2.5
2.6
V
0
0
0
VDDQ + 100mV
(2)
V
V
V
VIH
Input High Voltage
(Address & Control Inputs)
1.7
____
VIH
Input High Voltage - I/O(3)
1.7
____
VDDQ + 100mV(2)
____
0.7
VIL
(1)
Input Low Voltage
-0.5
V
5622 tbl 06
NOTES:
1. VIL > -1.5V for pulse width less than 10 ns.
2. VTERM must not exceed VDDQ + 100mV.
3. To select operation at 2.5V levels on the I/Os and controls of a given port, the
OPT pin for that port must be set to VIL (0V), and VDDQX for that port must be supplied
as indicated above.
Absolute Maximum Ratings(1)
Symbol
Rating
Commercial
& Industrial
Unit
VTERM(2)
Terminal Voltage
with Respect to
GND
-0.5 to +4.6
V
TBIAS
Temperature
Under Bias
-55 to +125
o
C
TSTG
Storage
Temperature
-65 to +150
o
C
IOUT
DC Output Current
Recommended DC Operating
Conditions with VDDQ at 3.3V
Symbol
50
mA
5622 tbl 05
NOTES:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may
cause permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated
in the operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect reliability.
2. VTERM must not exceed VDD + 150mV for more than 25% of the cycle time or
4ns maximum, and is limited to < 20mA for the period of VTERM > VDD + 150mV.
Parameter
Min.
Typ.
Max.
Unit
VDD
Core Supply Voltage
3.15
3.3
3.45
V
VDDQ
I/O Supply Voltage
(3)
3.15
3.3
3.45
V
VSS
Ground
0
0
0
V IH
Input High Voltage
(Address & Control Inputs)(3)
2.0
____
VDDQ + 150mV
(2)
V
V IH
Input High Voltage - I/O(3)
2.0
____
VDDQ + 150mV (2)
V
____
0.8
VIL
Input Low Voltage
-0.3
(1)
V
V
5622 tbl 07
NOTES:
1. VIL > -1.5V for pulse width less than 10 ns.
2. VTERM must not exceed V DDQ + 150mV.
3. To select operation at 3.3V levels on the I/Os and controls of a given port, the
OPT pin for that port must be set to VIH (3.3V), and VDDQX for that port must be
supplied as indicated above.
Capacitance(1)
(TA = +25°C, F = 1.0MHZ) TQFP ONLY
Symbol
CIN
COUT(3)
Parameter
Input Capacitance
Output Capacitance
Conditions(2)
Max.
Unit
VIN = 3dV
8
pF
VOUT = 3dV
10.5
pF
5622 tbl 08
NOTES:
1. These parameters are determined by device characterization, but are not
production tested.
2. 3dV references the interpolated capacitance when the input and output switch
from 0V to 3V or from 3V to 0V.
3. COUT also references CI/O.
7
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
DC Electrical Characteristics Over the Operating
Temperature and Supply Voltage Range (VDD = 3.3V ± 150mV)
70V631S
Symbol
Parameter
Test Conditions
(1)
Min.
Max.
Unit
10
µA
|ILI|
Input Leakage Current
VDDQ = Max., VIN = 0V to V DDQ
___
|ILO |
Output Leakage Current
CE0 = VIH or CE1 = VIL, VOUT = 0V to V DDQ
___
10
µA
VOL (3.3V)
Output Low Voltage(2)
IOL = +4mA, VDDQ = Min.
___
0.4
V
VOH (3.3V)
(2)
IOH = -4mA, VDDQ = Min.
2.4
___
V
(2)
IOL = +2mA, VDDQ = Min.
___
0.4
V
(2)
IOH = -2mA, VDDQ = Min.
2.0
___
V
VOL (2.5V)
VOH (2.5V)
Output High Voltage
Output Low Voltage
Output High Voltage
5622 tbl 09
NOTE:
1. At VDD < - 2.0V input leakages are undefined.
2. VDDQ is selectable (3.3V/2.5V) via OPT pins. Refer to p.5 for details.
DC Electrical Characteristics Over the Operating
Temperature and Supply Voltage Range(3) (VDD = 3.3V ± 150mV)
70V631S10
Com'l Only
Symbol
IDD
ISB1
ISB2
ISB3
ISB4
Parameter
Test Condition
Version
70V631S12
Com'l
& Ind
70V631S15
Com'l
Typ.(4)
Max.
Typ.(4)
Max.
Typ.(4)
Max.
Unit
mA
Dynamic Operating
Current (Both
Ports Active)
CEL and CER= VIL,
Outputs Disabled,
f = fMAX(1)
COM'L
S
340
500
315
465
300
440
IND
S
____
____
365
515
____
____
Standby Current
(Both Ports - TTL
Level Inputs)
CEL = CER = VIH
f = fMAX(1)
COM'L
S
115
165
90
125
75
100
IND
S
____
____
115
150
____
____
Standby Current
(One Port - TTL
Level Inputs)
CE"A" = VIL and CE"B" = VIH(5)
Active Port Outputs Disabled,
f=fMAX(1)
COM'L
S
225
340
200
325
175
315
IND
S
____
____
225
365
____
____
COM'L
S
3
15
3
15
3
15
IND
S
____
____
6
15
____
____
S
220
335
195
320
170
310
S
____
____
220
360
____
____
Full Standby Current Both Ports CEL and
(Both Ports - CMOS CER > VDD - 0.2V, VIN > VDD - 0.2V
Level Inputs)
or VIN < 0.2V, f = 0(2)
Full Standby Current
(One Port - CMOS
Level Inputs)
CE"A" < 0.2V and CE"B" > VDD - 0.2V(5) COM'L
VIN > VDD - 0.2V or V IN < 0.2V, Active
IND
Port, Outputs Disable d, f = fMAX(1)
mA
mA
mA
mA
5622 tbl 10
NOTES:
1. At f = fMAX, address and control lines (except Output Enable) are cycling at the maximum frequency read cycle of 1/tRC, using "AC TEST CONDITIONS" at input
levels of GND to 3V.
2. f = 0 means no address or control lines change. Applies only to input at CMOS level standby.
3. Port "A" may be either left or right port. Port "B" is the opposite from port "A".
4. VDD = 3.3V, TA = 25°C for Typ, and are not production tested. IDD DC(f=0) = 120mA (Typ).
5. CEX = VIL means CE0X = VIL and CE1X = VIH
CEX = VIH means CE0X = VIH or CE1X = V IL
CEX < 0.2V means CE0X < 0.2V and CE1X > VCC - 0.2V
CEX > VCC - 0.2V means CE0X > VCC - 0.2V or CE1X - 0.2V
"X" represents "L" for left port or "R" for right port.
8
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
AC Test Conditions (VDDQ - 3.3V/2.5V)
2.5V
GND to 3.0V / GND to 2.5V
Input Pulse Levels
2ns Max.
Input Rise/Fall Times
Input Timing Reference Levels
1.5V/1.25V
Output Reference Levels
1.5V/1.25V
833Ω
DATAOUT
Figures 1 and 2
Output Load
5pF*
770Ω
5622 tbl 11
,
Figure 2. Output Test Load
3.3V
590Ω
50Ω
50Ω
DATAOUT
1.5V/1.25
10pF
(Tester)
,
DATAOUT
435Ω
5pF*
5622 drw 03
Figure 1. AC Output Test load.
5622 drw 04
Figure 2. Output Test Load
(For tCKLZ , tCKHZ, tOLZ, and tOHZ).
*Including scope and jig.
10.5pF is the I/O capacitance of this
device, and 10pF is the AC Test Load
Capacitance.
7
6
5
4
∆tAA
(Typical, ns) 3
2
•
1
•
20.5
•
30
•
50
80
100
200
-1
Capacitance (pF)
5622 drw 05
Figure 3. Typical Output Derating (Lumped Capacitive Load).
9
,
,
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
AC Electrical Characteristics Over the
Operating Temperature and Supply Voltage Range(5)
70V631S10
Com'l Only
Symbol
Parameter
Min.
Max.
70V631S12
Com'l
& Ind
Min.
Max.
70V631S15
Com'l
Min.
Max.
Unit
READ CYCLE
tRC
Read Cycle Time
10
____
12
____
15
____
ns
tAA
Address Access Time
____
10
____
12
____
15
ns
Chip Enable Access Time
(3)
____
10
____
12
____
15
ns
tABE
Byte Enable Access Time
(3)
____
5
____
6
____
7
ns
tAOE
Output Enable Access Time
____
5
____
6
____
7
ns
tOH
Output Hold from Address Change
ns
tACE
Output Low-Z Time
tLZ
3
____
3
____
3
____
(1,2)
0
____
0
____
0
____
ns
(1,2)
0
4
0
6
0
8
ns
0
____
0
____
0
____
ns
tHZ
Output High-Z Time
tPU
Chip Enable to Power Up Time (2)
tPD
Chip Disable to Power Down Time (2)
____
10
____
10
____
15
ns
tSOP
Semaphore Flag Update Pulse (OE or SEM)
____
4
____
6
____
8
ns
tSAA
Semaphore Address Access Time
3
10
3
12
3
20
ns
5622 tbl 12
AC Electrical Characteristics Over the
Operating Temperature and Supply Voltage(5)
70V631S10
Com'l Only
Symbol
Parameter
70V631S12
Com'l
& Ind
70V631S15
Com'l
Min.
Max.
Min.
Max.
Min.
Max.
Unit
10
____
12
____
15
____
ns
tEW
Chip Enable to End-of-Write
(3)
8
____
10
____
12
____
ns
tAW
Address Valid to End-of-Write
8
____
10
____
12
____
ns
0
____
0
____
0
____
ns
ns
WRITE CYCLE
tWC
Write Cycle Time
(3)
tAS
Address Set-up Time
tWP
Write Pulse Width
8
____
10
____
12
____
tWR
Write Recovery Time
0
____
0
____
0
____
ns
tDW
Data Valid to End-of-Write
6
____
8
____
10
____
ns
tDH
Data Hold Time (4)
0
____
0
____
0
____
ns
tWZ
Write Enable to Output in High-Z(1,2)
____
4
____
4
____
4
ns
tOW
Output Active from End-of-Write
(1,2,4)
0
____
0
____
0
____
ns
tSWRD
SEM Flag Write to Read Time
5
____
5
____
5
____
ns
SEM Flag Contention Window
5
____
5
____
5
____
ns
tSPS
5622 tbl 13
NOTES:
1. Transition is measured 0mV from Low or High-impedance voltage with Output Test Load (Figure 2).
2. This parameter is guaranted by device characterization, but is not production tested.
3. To access RAM, CE= V IL and SEM = VIH. To access semaphore, CE = VIH and SEM = VIL. Either condition must be valid for the entire tEW time.
4. The specification for tDH must be met by the device supplying write data to the RAM under all operating conditions. Although tDH and tOW values will vary over voltage
and temperature, the actual tDH will always be smaller than the actual tOW.
5. These values are valid regardless of the power supply level selected for I/O and control signals (3.3V/2.5V). See page 5 for details.
10
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Waveform of Read Cycles(5)
tRC
ADDR
(4)
tAA
(4)
tACE
(6)
CE
tAOE
(4)
OE
tABE (4)
UB, LB
R/W
tLZ
tOH
(1)
DATAOUT
VALID DATA
(4)
tHZ
(2)
BUSYOUT
tBDD
(3,4)
5622 drw 06
NOTES:
1. Timing depends on which signal is asserted last, OE, CE, LB or UB.
2. Timing depends on which signal is de-asserted first CE, OE, LB or UB.
3. tBDD delay is required only in cases where the opposite port is completing a write operation to the same address location. For simultaneous read operations BUSY
has no relation to valid output data.
4. Start of valid data depends on which timing becomes effective last tAOE, tACE, tAA or tBDD .
5. SEM = VIH.
Timing of Power-Up Power-Down
CE
tPU
tPD
ICC
50%
50%
ISB
.
5622 drw 07
11
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Timing Waveform of Write Cycle No. 1, R/W Controlled Timing(1,5,8)
tWC
ADDRESS
tHZ
(7)
OE
tAW
CE or SEM
(9)
(9)
UB, LB
tAS (6)
tWP
(2)
tWR
(3)
R/W
tWZ (7)
tOW
(4)
DATAOUT
(4)
tDW
tDH
DATAIN
5622 drw 08
Timing Waveform of Write Cycle No. 2, CE Controlled Timing(1,5)
tWC
ADDRESS
tAW
CE or SEM
(9)
(6)
tAS
tWR(3)
tEW (2)
UB, LB(9)
R/W
tDW
tDH
DATAIN
5622 drw 09
NOTES:
1. R/W or CE or BEn = VIH during all address transitions.
2. A write occurs during the overlap (tEW or tWP) of a CE = VIL and a R/W = VIL for memory array writing cycle.
3. tWR is measured from the earlier of CE or R/W (or SEM or R/W) going HIGH to the end of write cycle.
4. During this period, the I/O pins are in the output state and input signals must not be applied.
5. If the CE or SEM = VIL transition occurs simultaneously with or after the R/W = VIL transition, the outputs remain in the High-impedance state.
6. Timing depends on which enable signal is asserted last, CE or R/W.
7. This parameter is guaranteed by device characterization, but is not production tested. Transition is measured 0mV from steady state with the Output Test Load
(Figure 2).
8. If OE = VIL during R/W controlled write cycle, the write pulse width must be the larger of tWP or (tWZ + tDW ) to allow the I/O drivers to turn off and data to be
placed on the bus for the required tDW . If OE = VIH during an R/W controlled write cycle, this requirement does not apply and the write pulse can be as short as the
specified tWP .
9. To access RAM, CE = VIL and SEM = VIH. To access semaphore, CE = VIH and SEM = VIL. tEW must be met for either condition.
12
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Timing Waveform of Semaphore Read after Write Timing, Either Side(1)
tSAA
A0-A2
VALID ADDRESS
tAW
VALID ADDRESS
tWR
tACE
tEW
SEM/UB/LB(1)
tOH
tSOP
tDW
I/O
DATA OUT(2)
VALID
DATAIN VALID
tAS
tWP
tDH
R/W
tSWRD
OE
tAOE
tSOP
Write Cycle
Read Cycle
5622 drw 10
NOTES:
1. CE = VIH or UB and LB = VIH for the duration of the above timing (both write and read cycle) (Refer to Chip Enable Truth Table). Refer also to Truth Table II for appropriate
UB/LB controls.
2. "DATAOUT VALID" represents all I/O's (I/O0 - I/O17 ) equal to the semaphore value.
Timing Waveform of Semaphore Write Contention(1,3,4)
A0"A"-A2"A"
(2)
SIDE
"A"
MATCH
R/W"A"
SEM"A"
tSPS
A0"B"-A2"B"
(2)
SIDE
"B"
MATCH
R/W"B"
SEM"B"
5622 drw 11
NOTES:
1. DOR = DOL = VIL, CEL = CER = VIH. Refer also to Truth Table II for appropriate UB/LB controls.
2. All timing is the same for left and right ports. Port "A" may be either left or right port. "B" is the opposite from port "A".
3. This parameter is measured from R/W"A" or SEM"A" going HIGH to R/W"B" or SEM"B" going HIGH.
4. If tSPS is not satisfied,the semaphore will fall positively to one side or the other, but there is no guarantee which side will be granted the semaphore flag.
13
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
AC Electrical Characteristics Over the
Operating Temperature and Supply Voltage Range
70V631S10
Com'l Only
Symbol
Parameter
70V631S12
Com'l
& Ind
70V631S15
Com'l
Min.
Max.
Min.
Max.
Min.
Max.
Unit
BUSY TIMING (M/S=VIH)
tBAA
BUSY Access Time from Address Match
____
10
____
12
____
15
ns
tBDA
BUSY Disable Time from Address Not Matched
____
10
____
12
____
15
ns
tBAC
BUSY Access Time from Chip Enable Low
____
10
____
12
____
15
ns
tBDC
BUSY Disable Time from Chip Enable High
____
10
____
12
____
15
ns
tAPS
Arbitration Priority Set-up Time (2)
5
____
5
____
5
____
ns
____
10
____
12
____
15
ns
8
____
10
____
12
____
ns
tBDD
tWH
(3)
BUSY Disable to Valid Data
(5)
Write Hold After BUSY
BUSY TIMING (M/S=VIL)
tWB
BUSY Input to Write(4)
0
____
0
____
0
____
ns
tWH
Write Hold After BUSY(5)
8
____
10
____
12
____
ns
PORT-TO-PORT DELAY TIMING
tWDD
Write Pulse to Data Delay(1)
____
22
____
25
____
30
ns
tDDD
Write Data Valid to Read Data Delay (1)
____
20
____
22
____
25
ns
5622 tbl 14
NOTES:
1. Port-to-port delay through RAM cells from writing port to reading port, refer to "Timing Waveform of Write with Port-to-Port Read and BUSY (M/S = VIH)".
2. To ensure that the earlier of the two ports wins.
3. tBDD is a calculated parameter and is the greater of the Max. spec, tWDD – tWP (actual), or tDDD – tDW (actual).
4. To ensure that the write cycle is inhibited on port "B" during contention on port "A".
5. To ensure that a write cycle is completed on port "B" after contention on port "A".
14
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Timing Waveform of Write with Port-to-Port Read and BUSY (M/S = VIH)(2,4,5)
tWC
MATCH
ADDR"A"
tWP
R/W"A"
tDW
tDH
VALID
DATAIN "A"
tAPS
(1)
MATCH
ADDR"B"
tBAA
tBDA
tBDD
BUSY"B"
tWDD
DATAOUT "B"
VALID
tDDD (3)
NOTES:
1. To ensure that the earlier of the two ports wins. tAPS is ignored for M/S = VIL (SLAVE).
2. CEL = CER = VIL.
3. OE = VIL for the reading port.
4. If M/S = VIL (slave), BUSY is an input. Then for this example BUSY"A" = VIH and BUSY"B" input is shown above.
5. All timing is the same for left and right ports. Port "A" may be either the left or right port. Port "B" is the port opposite from port "A".
Timing Waveform of Write with BUSY (M/S = VIL)
tWP
R/W"A"
tWB(3)
BUSY"B"
tWH
R/W"B"
(1)
(2)
5622 drw 13
NOTES:
1. tWH must be met for both BUSY input (SLAVE) and output (MASTER).
2. BUSY is asserted on port "B" blocking R/W"B" , until BUSY"B" goes HIGH.
3. tWB is only for the 'slave' version.
15
5622 drw 12
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Waveform of BUSY Arbitration Controlled by CE Timing (M/S = VIH)(1)
ADDR"A"
and "B"
ADDRESSES MATCH
CE"A"
tAPS (2)
CE"B"
tBAC
tBDC
BUSY"B"
5622 drw 14
Waveform of BUSY Arbitration Cycle Controlled by Address Match
Timing (M/S = VIH)(1)
ADDR"A"
ADDRESS "N"
tAPS (2)
ADDR"B"
MATCHING ADDRESS "N"
tBAA
tBDA
BUSY"B"
5622 drw 15
NOTES:
1. All timing is the same for left and right ports. Port “A” may be either the left or right port. Port “B” is the port opposite from port “A”.
2. If tAPS is not satisfied, the BUSY signal will be asserted on one side or another but there is no guarantee on which side BUSY will be asserted.
AC Electrical Characteristics Over the
Operating Temperature and Supply Voltage Range
70V631S10
Com'l Only
Symbol
Parameter
70V631S12
Com'l
& Ind
70V631S15
Com'l
Min.
Max.
Min.
Max.
Min.
Max.
Unit
INTERRUPT TIMING
tAS
Address Set-up Time
0
____
0
____
0
____
ns
tWR
Write Recovery Time
0
____
0
____
0
____
ns
tINS
Interrupt Set Time
____
10
____
12
____
15
ns
tINR
Interrupt Reset Time
____
10
____
12
____
15
ns
5622 tbl 15
16
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Waveform of Interrupt Timing(1)
tWC
INTERRUPT SET ADDRESS
ADDR"A"
(2)
tWR (4)
tAS(3)
CE"A"
R/W"A"
tINS
(3)
INT"B"
5622 drw 16
tRC
ADDR"B"
INTERRUPT CLEAR ADDRESS
tAS
(2)
(3)
CE"B"
OE"B"
tINR (3)
INT"B"
5622 drw 17
NOTES:
1. All timing is the same for left and right ports. Port “A” may be either the left or right port. Port “B” is the port opposite from port “A”.
2. Refer to Interrupt Truth Table.
3. Timing depends on which enable signal (CE or R/W) is asserted last.
4. Timing depends on which enable signal (CE or R/W) is de-asserted first.
Truth Table III — Interrupt Flag(1,4)
Left Port
R/WL
CEL
L
L
X
X
X
X
X
L
Right Port
OEL
A17L-A0L
X
3FFFF
X
X
L
X
X
3FFFE
INTL
R/WR
CER
OER
A17R-A0R
INTR
X
X
X
X
X
L(2)
X
(3)
Function
Set Right INTR Flag
X
L
L
3FFFF
H
Reset Right INTR Flag
(3)
L
L
X
3FFFE
X
Set Left INTL Flag
(2)
X
X
X
X
X
Reset Left INTL Flag
L
H
5622 tbl 16
NOTES:
1. Assumes BUSYL = BUSYR =VIH.
2. If BUSYL = V IL, then no change.
3. If BUSYR = VIL, then no change.
4. INTL and INTR must be initialized at power-up.
17
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Truth Table IV —
Address BUSY Arbitration
Inputs
Outputs
CEL
CER
AOL-A17L
AOR-A17R
BUSYL(1)
BUSYR(1)
Function
X
X
NO MATCH
H
H
Normal
H
X
MATCH
H
H
Normal
X
H
MATCH
H
H
Normal
L
L
MATCH
(2)
(2)
Write Inhibit(3)
5622 tbl 17
NOTES:
1. Pins BUSYL and BUSYR are both outputs when the part is configured as a master. Both are inputs when configured as a slave. BUSY outputs on the IDT70V631
are push-pull, not open drain outputs. On slaves the BUSY input internally inhibits writes.
2. "L" if the inputs to the opposite port were stable prior to the address and enable inputs of this port. "H" if the inputs to the opposite port became stable after the address
and enable inputs of this port. If tAPS is not met, either BUSYL or BUSY R = LOW will result. BUSYL and BUSYR outputs can not be LOW simultaneously.
3. Writes to the left port are internally ignored when BUSYL outputs are driving LOW regardless of actual logic level on the pin. Writes to the right port are internally ignored
when BUSYR outputs are driving LOW regardless of actual logic level on the pin.
Truth Table V — Example of Semaphore Procurement Sequence(1,2,3)
Functions
D0 - D17 Left
D0 - D17 Right
Status
No Action
1
1
Semaphore free
Left Port Writes "0" to Semaphore
0
1
Left port has semaphore token
Right Port Writes "0" to Semaphore
0
1
No change. Right side has no write access to semaphore
Left Port Writes "1" to Semaphore
1
0
Right port obtains semaphore token
Left Port Writes "0" to Semaphore
1
0
No change. Left port has no write access to semaphore
Right Port Writes "1" to Semaphore
0
1
Left port obtains semaphore token
Left Port Writes "1" to Semaphore
1
1
Semaphore free
Right Port Writes "0" to Semaphore
1
0
Right port has semaphore token
Right Port Writes "1" to Semaphore
1
1
Semaphore free
Left Port Writes "0" to Semaphore
0
1
Left port has semaphore token
Left Port Writes "1" to Semaphore
1
1
Semaphore free
NOTES:
1. This table denotes a sequence of events for only one of the eight semaphores on the IDT70V631.
2. There are eight semaphore flags written to via I/O0 and read from all I/O's (I/O0-I/O17 ). These eight semaphores are addressed by A0 - A2.
3. CE = VIH, SEM = V IL to access the semaphores. Refer to the Semaphore Read/Write Control Truth Table.
Functional Description
The IDT70V631 provides two ports with separate control, address
and I/O pins that permit independent access for reads or writes to any
location in memory. The IDT70V631 has an automatic power down feature
controlled by CE. The CE0 and CE1 control the on-chip power down
circuitry that permits the respective port to go into a standby mode when
not selected (CE = HIGH). When a port is enabled, access to the entire
memory array is permitted.
Interrupts
If the user chooses the interrupt function, a memory location (mail
box or message center) is assigned to each port. The left port interrupt
flag (INTL) is asserted when the right port writes to memory location
18
5622 tbl 18
3FFFE (HEX), where a write is defined as CER = R/WR = VIL per the
Truth Table. The left port clears the interrupt through access of
address location 3FFFE when CEL = OEL = VIL, R/W is a "don't care".
Likewise, the right port interrupt flag (INTR) is asserted when the left
port writes to memory location 3FFFF (HEX) and to clear the interrupt
flag (INTR), the right port must read the memory location 3FFFF. The
message (18 bits) at 3FFFE or 3FFFF is user-defined since it is an
addressable SRAM location. If the interrupt function is not used,
address locations 3FFFE and 3FFFF are not used as mail boxes, but
as part of the random access memory. Refer to Truth Table III for
the interrupt operation.
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Busy Logic
address signals only. It ignores whether an access is a read or write.
In a master/slave array, both address and chip enable must be valid
long enough for a BUSY flag to be output from the master before the
actual write pulse can be initiated with the R/W signal. Failure to
observe this timing can result in a glitched internal write inhibit signal
and corrupted data in the slave.
Busy Logic provides a hardware indication that both ports of the RAM
have accessed the same location at the same time. It also allows one of the
two accesses to proceed and signals the other side that the RAM is “Busy”.
The BUSY pin can then be used to stall the access until the operation on
the other side is completed. If a write operation has been attempted from
the side that receives a BUSY indication, the write signal is gated internally
to prevent the write from proceeding.
The use of BUSY logic is not required or desirable for all applications.
In some cases it may be useful to logically OR the BUSY outputs together
and use any BUSY indication as an interrupt source to flag the event of
an illegal or illogical operation. If the write inhibit function of BUSY logic is
not desirable, the BUSY logic can be disabled by placing the part in slave
mode with the M/S pin. Once in slave mode the BUSY pin operates solely
as a write inhibit input pin. Normal operation can be programmed by tying
the BUSY pins HIGH. If desired, unintended write operations can be
prevented to a port by tying the BUSY pin for that port LOW.
The BUSY outputs on the IDT70V631 RAM in master mode, are
push-pull type outputs and do not require pull up resistors to operate.
If these RAMs are being expanded in depth, then the BUSY indication
for the resulting array requires the use of an external AND gate.
Semaphores
A18
CE0
MASTER
Dual Port RAM
BUSYL
BUSYR
CE0
SLAVE
Dual Port RAM
BUSYL
BUSYR
CE1
MASTER
Dual Port RAM
CE1
SLAVE
Dual Port RAM
BUSYL
BUSYL
BUSYR
BUSYR
5622 drw 18
Industrial and Commercial Temperature Ranges
.
Figure 3. Busy and chip enable routing for both width and depth
expansion with IDT70V631 RAMs.
Width Expansion with Busy Logic
Master/Slave Arrays
When expanding an IDT70V631 RAM array in width while using
BUSY logic, one master part is used to decide which side of the RAMs
array will receive a BUSY indication, and to output that indication. Any
number of slaves to be addressed in the same address range as the
master use the BUSY signal as a write inhibit signal. Thus on the
IDT70V631 RAM the BUSY pin is an output if the part is used as a
master (M/S pin = VIH), and the BUSY pin is an input if the part used
as a slave (M/S pin = VIL) as shown in Figure 3.
If two or more master parts were used when expanding in width, a
split decision could result with one master indicating BUSY on one side
of the array and another master indicating BUSY on one other side of
the array. This would inhibit the write operations from one port for part
of a word and inhibit the write operations from the other port for the
other part of the word.
The BUSY arbitration on a master is based on the chip enable and
The IDT70V631 is an extremely fast Dual-Port 256K x 18 CMOS
Static RAM with an additional 8 address locations dedicated to binary
semaphore flags. These flags allow either processor on the left or right
side of the Dual-Port RAM to claim a privilege over the other processor
for functions defined by the system designer’s software. As an example, the semaphore can be used by one processor to inhibit the
other from accessing a portion of the Dual-Port RAM or any other
shared resource.
The Dual-Port RAM features a fast access time, with both ports
being completely independent of each other. This means that the
activity on the left port in no way slows the access time of the right port.
Both ports are identical in function to standard CMOS Static RAM and
can be read from or written to at the same time with the only possible
conflict arising from the simultaneous writing of, or a simultaneous
READ/WRITE of, a non-semaphore location. Semaphores are protected against such ambiguous situations and may be used by the
system program to avoid any conflicts in the non-semaphore portion
of the Dual-Port RAM. These devices have an automatic power-down
feature controlled by CE, the Dual-Port RAM enable, and SEM, the
semaphore enable. The CE and SEM pins control on-chip power
down circuitry that permits the respective port to go into standby mode
when not selected.
Systems which can best use the IDT70V631 contain multiple
processors or controllers and are typically very high-speed systems
which are software controlled or software intensive. These systems
can benefit from a performance increase offered by the IDT70V631s
hardware semaphores, which provide a lockout mechanism without
requiring complex programming.
Software handshaking between processors offers the maximum in
system flexibility by permitting shared resources to be allocated in
varying configurations. The IDT70V631 does not use its semaphore
flags to control any resources through hardware, thus allowing the
system designer total flexibility in system architecture.
An advantage of using semaphores rather than the more common
methods of hardware arbitration is that wait states are never incurred
in either processor. This can prove to be a major advantage in very
high-speed systems.
How the Semaphore Flags Work
The semaphore logic is a set of eight latches which are independent of the Dual-Port RAM. These latches can be used to pass a flag,
or token, from one port to the other to indicate that a shared resource
is in use. The semaphores provide a hardware assist for a use
assignment method called “Token Passing Allocation.” In this method,
the state of a semaphore latch is used as a token indicating that a
shared resource is in use. If the left processor wants to use this
resource, it requests the token by setting the latch. This processor then
19
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
question. Meanwhile, if a processor on the right side attempts to write
a zero to the same semaphore flag it will fail, as will be verified by the
fact that a one will be read from that semaphore on the right side
during subsequent read. Had a sequence of READ/WRITE been
used instead, system contention problems could have occurred during
the gap between the read and write cycles.
It is important to note that a failed semaphore request must be
followed by either repeated reads or by writing a one into the same
location. The reason for this is easily understood by looking at the
simple logic diagram of the semaphore flag in Figure 4. Two semaphore request latches feed into a semaphore flag. Whichever latch is
first to present a zero to the semaphore flag will force its side of the
semaphore flag LOW and the other side HIGH. This condition will
verifies its success in setting the latch by reading it. If it was successful, it
proceeds to assume control over the shared resource. If it was not
successful in setting the latch, it determines that the right side processor
has set the latch first, has the token and is using the shared resource.
The left processor can then either repeatedly request that
semaphore’s status or remove its request for that semaphore to
perform another task and occasionally attempt again to gain control of
the token via the set and test sequence. Once the right side has
relinquished the token, the left side should succeed in gaining control.
The semaphore flags are active LOW. A token is requested by
writing a zero into a semaphore latch and is released when the same
side writes a one to that latch.
The eight semaphore flags reside within the IDT70V631 in a
separate memory space from the Dual-Port RAM. This address space
is accessed by placing a low input on the SEM pin (which acts as a chip
select for the semaphore flags) and using the other control pins
(Address, CE, R/W and LB/UB) as they would be used in accessing a
standard Static RAM. Each of the flags has a unique address which
can be accessed by either side through address pins A0 – A2. When
accessing the semaphores, none of the other address pins has
any effect.
When writing to a semaphore, only data pin D0 is used. If a low level
is written into an unused semaphore location, that flag will be set to
a zero on that side and a one on the other side (see Truth Table V).
That semaphore can now only be modified by the side showing the zero.
When a one is written into the same location from the same side, the
flag will be set to a one for both sides (unless a semaphore request
from the other side is pending) and then can be written to by both sides.
The fact that the side which is able to write a zero into a semaphore
subsequently locks out writes from the other side is what makes
semaphore flags useful in interprocessor communications. (A thorough discussion on the use of this feature follows shortly.) A zero
written into the same location from the other side will be stored in the
semaphore request latch for that side until the semaphore is freed by
the first side.
When a semaphore flag is read, its value is spread into all data
bits so that a flag that is a one reads as a one in all data bits and a flag
containing a zero reads as all zeros. The read value is latched into one
side’s output register when that side's semaphore, byte select (SEM,
LB/UB) and output enable (OE) signals go active. This serves to disallow
the semaphore from changing state in the middle of a read cycle due to a
write cycle from the other side. Because of this latch, a repeated read
of a semaphore in a test loop must cause either signal (SEM or OE) to
go inactive or the output will never change. However, during reads LB
and UB function only as an output for semaphore. They do not have any
iinfluence on the semaphore control logic.
A sequence WRITE/READ must be used by the semaphore in
order to guarantee that no system level contention will occur. A
processor requests access to shared resources by attempting to write
a zero into a semaphore location. If the semaphore is already in use,
the semaphore request latch will contain a zero, yet the semaphore
flag will appear as one, a fact which the processor will verify by the
subsequent read (see Table V). As an example, assume a processor
writes a zero to the left port at a free semaphore location. On a
subsequent read, the processor will verify that it has written successfully to that location and will assume control over the resource in
L PORT
R PORT
SEMAPHORE
REQUEST FLIP FLOP
D0
WRITE
D
Q
SEMAPHORE
REQUEST FLIP FLOP
Q
D
SEMAPHORE
READ
D0
WRITE
SEMAPHORE
READ
Figure 4. IDT70V631 Semaphore Logic
5622 drw 19
continue until a one is written to the same semaphore request latch.
Should the other side’s semaphore request latch have been written to
a zero in the meantime, the semaphore flag will flip over to the other
side as soon as a one is written into the first side’s request latch. The
second side’s flag will now stay LOW until its semaphore request latch
is written to a one. From this it is easy to understand that, if a
semaphore is requested and the processor which requested it no
longer needs the resource, the entire system can hang up until a one
is written into that semaphore request latch.
The critical case of semaphore timing is when both sides request
a single token by attempting to write a zero into it at the same time. The
semaphore logic is specially designed to resolve this problem. If
simultaneous requests are made, the logic guarantees that only one
side receives the token. If one side is earlier than the other in making
the request, the first side to make the request will receive the token. If
both requests arrive at the same time, the assignment will be arbitrarily
made to one port or the other.
One caution that should be noted when using semaphores is that
semaphores alone do not guarantee that access to a resource is
secure. As with any powerful programming technique, if semaphores
are misused or misinterpreted, a software error can easily happen.
Initialization of the semaphores is not automatic and must be
handled via the initialization program at power-up. Since any semaphore request flag which contains a zero must be reset to a one,
all semaphores on both sides should have a one written into them
at initialization from both sides to assure that they will be free
when needed.
20
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
JTAG Timing Specifications
tJF
tJCL
tJCYC
tJR
tJCH
TCK
Device Inputs(1)/
TDI/TMS
tJS
Device Outputs(2)/
TDO
tJDC
tJH
tJRSR
tJCD
TRST
x
5622 drw 20
tJRST
NOTES:
1. Device inputs = All device inputs except TDI, TMS, and TRST.
2. Device outputs = All device outputs except TDO.
JTAG AC Electrical
Characteristics(1,2,3,4)
Symbol
Parameter
Min.
Max.
Units
tJCYC
JTAG Clock Input Period
100
____
ns
tJCH
JTAG Clock HIGH
40
____
ns
tJCL
JTAG Clock Low
40
____
ns
tJR
JTAG Clock Rise Time
____
(1)
3
ns
tJF
JTAG Clock Fall Time
____
3(1)
ns
tJRST
JTAG Reset
50
____
ns
tJRSR
JTAG Reset Recovery
50
____
ns
tJCD
JTAG Data Output
____
25
ns
tJDC
JTAG Data Output Hold
0
____
ns
tJS
JTAG Setup
15
____
ns
tJH
JTAG Hold
15
____
ns
5622 tbl 19
NOTES:
1. Guaranteed by design.
2. 30pF loading on external output signals.
3. Refer to AC Electrical Test Conditions stated earlier in this document.
4. JTAG operations occur at one speed (10MHz). The base device may run at
any speed specified in this datasheet.
21
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Identification Register Definitions
Instruction Field
Value
Revision Number (31:28)
Description
0x0
Reserved for version number
IDT Device ID (27:12)
0x304
Defines IDT part number
IDT JEDEC ID (11:1)
0x33
Allows unique identification of device vendor as IDT
ID Register Indicator Bit (Bit 0)
1
Indicates the presence of an ID register
5622 tbl 20
Scan Register Sizes
Register Name
Bit Size
Instruction (IR)
4
Bypass (BYR)
1
Identification (IDR)
Boundary Scan (BSR)
32
Note (3)
5622 tbl 21
System Interface Parameters
Instruction
Code
Description
EXTEST
0000
Forces contents of the bound ary scan cells onto the device outputs(1).
Places the boundary scan register (BSR) between TDI and TDO.
BYPASS
1111
Places the bypass registe r (BYR) between TDI and TDO.
IDCODE
0010
Loads the ID register (IDR) with the vendor ID code and places the
register between TDI and TDO.
0100
Places the bypass register (BYR) between TDI and TDO. Forces all
device output drivers to a High-Z state.
HIGHZ
Uses BYR. Forces contents of the boundary scan cells onto the device
outputs. Places the bypass registe r (BYR) between TDI and TDO.
CLAMP
0011
SAMPLE/PRELOAD
0001
Places the boundary scan register (BSR) between TDI and TDO.
SAMPLE allows data from device inputs (2) and outputs(1) to be captured
in the boundary scan cells and shifted serially through TDO. PRELOAD
allows data to be input serially into the boundary scan cells via the TDI.
All other codes
Several combinations are reserved. Do not use codes other than those
identified above.
RESERVED
NOTES:
1. Device outputs = All device outputs except TDO.
2. Device inputs = All device inputs except TDI, TMS, and TRST.
3. The Boundary Scan Descriptive Language (BSDL) file for this device is available on the IDT website (www.idt.com), or by contacting your local
IDT sales representative.
22
5622 tbl 22
IDT70V631S
High-Speed 3.3V 256K x 18 Asynchronous Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Ordering Information
IDT XXXXX
Device
Type
A
999
A
A
Power
Speed
Package
Process/
Temperature
Range
Blank
I(1)
Commercial (0°C to +70°C)
Industrial (-40°C to +85°C)
BF
PRF
BC
208-ball fpBGA (BF-208)
128-pin TQFP (PK-128)
256-ball BGA (BC-256)
10
12
15
Commercial Only
Commercial & Industrial
Commercial Only
S
Standard Power
Speed in nanoseconds
70V631 4608K (256K x 18) 3.3V
Asynchronous Dual-Port RAM
5622 drw 21
NOTE:
1. Contact your local sales office for industrial temp range for other speeds, packages and powers.
Datasheet Document History:
06/01/00:
08/07/00:
06/20/01:
08/08/01:
10/01/03:
Initial Public Offering
Page 6, 13 & 20 Inserted additional LB and UB information
Page 1 Added JTAG information for TQFP package
Page 14 Increased BUSY TIMING parameters tBDA, tBAC, tBDC and tBDD for all speeds
Page 21 Changed maximum value for JTAG AC Electrical Characteristics for tJCD from 20ns to 25ns
Page 3 Corrected pin 4 designation error from A17R to A17L on PK-128 pinout
Removed Preliminary status
Page 2, 3 & 4 Added date revision for pin configurations
Page 8, 10, 14 & 16 Removed I-temp 15ns speed from DC & AC Electrical Characteristics Tables
Page 23 Removed I-temp 15ns speed from ordering information
Added I-temp footnote to ordering information
Page 1 & 23 Replaced TM logo with ® logo
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23
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