CY7C1318CV18
CY7C1320CV18
18-Mbit DDR II SRAM 2-Word
Burst Architecture
Features
Functional Description
■ 18-Mbit Density (1M x 18, 512K x 36)
■ 267 MHz Clock for high Bandwidth
The CY7C1318CV18, and CY7C1320CV18 are 1.8V
Synchronous Pipelined SRAMs equipped with DDR II archi-
tecture. The DDR II consists of an SRAM core with advanced
synchronous peripheral circuitry and a one-bit burst counter.
Addresses for read and write are latched on alternate rising
edges of the input (K) clock. Write data is registered on the rising
edges of both K and K. Read data is driven on the rising edges
of C and C if provided, or on the rising edge of K and K if C/C are
not provided. For CY7C1318CV18 and CY7C1320CV18, the
burst counter takes in the least significant bit of the external
address and bursts two 18-bit words (in the case of
CY7C1318CV18) of two 36-bit words (in the case of
CY7C1320CV18) sequentially into or out of the device.
■ 2-word Burst for reducing Address Bus Frequency
■ Double Data Rate (DDR) Interfaces
(data transferred at 534 MHz) at 267 MHz
■ Two Input Clocks (K and K) for precise DDR Timing
❐ SRAM uses rising edges only
■ Two Input Clocks for Output Data (C and C) to minimize Clock
Skew and Flight Time mismatches
■ Echo Clocks (CQ and CQ) simplify Data Capture in High Speed
Asynchronous inputs include an output impedance matching
input (ZQ). Synchronous data outputs (Q, sharing the same
physical pins as the data inputs, D) are tightly matched to the two
output echo clocks CQ/CQ, eliminating the need to capture data
separately from each individual DDR SRAM in the system
design. Output data clocks (C/C) enable maximum system
clocking and data synchronization flexibility.
Systems
■ Synchronous internally Self-timed Writes
■ DDR II operates with 1.5 Cycle Read Latency when the DLL is
enabled
■ Operates similar to a DDR I Device with one Cycle Read
Latency in DLL Off Mode
All synchronous inputs pass through input registers controlled by
the K or K input clocks. All data outputs pass through output
registers controlled by the C or C (or K or K in a single clock
domain) input clocks. Writes are conducted with on-chip
synchronous self-timed write circuitry.
■ 1.8V Core Power Supply with HSTL Inputs and Outputs
■ Variable drive HSTL Output Buffers
■ Expanded HSTL Output Voltage (1.4V–V
)
DD
■ Available in 165-Ball FBGA Package (13 x 15 x 1.4 mm)
■ Offered in both Pb-free and non Pb-free Packages
■ JTAG 1149.1 compatible Test Access Port
■ Delay Lock Loop (DLL) for accurate Data Placement
Configurations
CY7C1318CV18 – 1M x 18
CY7C1320CV18 – 512K x 36
Selection Guide
Description
267 MHz
267
250 MHz
250
200 MHz
200
167 MHz
167
Unit
MHz
mA
Maximum Operating Frequency
Maximum Operating Current
x18
x36
805
730
600
510
855
775
635
540
Cypress Semiconductor Corporation
Document Number: 001-07160 Rev. *F
•
198 Champion Court
•
San Jose, CA 95134-1709
•
408-943-2600
Revised August 24, 2009
CY7C1318CV18
CY7C1320CV18
Pin Configuration
[1]
The pin configuration for CY7C1318CV18 and CY7C1320CV18 follow.
165-Ball FBGA (13 x 15 x 1.4 mm) Pinout
CY7C1318CV18 (1M x 18)
1
CQ
NC
NC
NC
NC
NC
NC
DOFF
NC
NC
NC
NC
NC
NC
TDO
2
NC/72M
DQ9
NC
3
4
R/W
A
5
6
K
7
8
LD
A
9
10
NC/36M
NC
11
CQ
A
B
C
D
E
F
A
BWS
NC/144M
A
1
NC
NC/288M
A
K
BWS
A
NC
NC
NC
NC
NC
NC
DQ8
NC
0
NC
V
V
A0
V
DQ7
NC
SS
SS
SS
SS
NC
DQ10
DQ11
NC
V
V
V
V
V
V
NC
SS
SS
DD
DD
DD
DD
DD
SS
SS
SS
SS
SS
SS
SS
SS
SS
SS
SS
DD
DD
DD
DD
DD
NC
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
NC
DQ6
DQ5
NC
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DQ12
NC
V
V
V
V
V
V
V
V
V
V
NC
G
H
J
DQ13
NC
V
V
V
V
REF
ZQ
REF
DDQ
DDQ
NC
NC
NC
DQ14
NC
NC
DQ4
NC
NC
K
L
NC
NC
NC
NC
NC
A
DQ3
DQ2
NC
DQ15
NC
V
V
V
V
NC
SS
SS
SS
SS
M
N
P
R
NC
V
V
DQ1
NC
SS
SS
SS
NC
DQ16
DQ17
A
V
A
A
A
A
C
C
A
A
A
V
NC
SS
NC
A
A
A
A
NC
DQ0
TDI
TCK
TMS
CY7C1320CV18 (512K x 36)
1
CQ
NC
NC
NC
NC
NC
NC
DOFF
NC
NC
NC
NC
NC
NC
TDO
2
3
4
5
BWS
BWS
A
6
K
7
BWS
BWS
A
8
9
10
NC/72M
NC
11
A
B
C
D
E
F
NC/144M NC/36M
R/W
A
LD
A
A
CQ
2
3
1
0
DQ27
NC
DQ18
DQ28
DQ19
DQ20
DQ21
DQ22
K
NC
NC
NC
NC
NC
NC
DQ8
DQ7
DQ16
DQ6
DQ5
DQ14
ZQ
V
V
A0
V
DQ17
NC
SS
SS
SS
SS
DQ29
NC
V
V
V
V
V
V
SS
SS
DD
DD
DD
DD
DD
SS
SS
SS
SS
SS
SS
SS
SS
SS
SS
SS
DD
DD
DD
DD
DD
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
DQ15
NC
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DDQ
DQ30
DQ31
V
V
V
V
V
V
V
V
V
V
G
H
J
NC
V
V
V
V
REF
REF
DDQ
DDQ
NC
NC
DQ32
DQ23
DQ24
DQ34
DQ25
DQ26
A
NC
DQ13
DQ12
NC
DQ4
DQ3
DQ2
DQ1
DQ10
DQ0
TDI
K
L
NC
NC
NC
NC
NC
A
DQ33
NC
V
V
SS
SS
SS
SS
M
N
P
R
V
V
V
V
DQ11
NC
SS
SS
SS
DQ35
NC
V
A
A
A
A
C
C
A
A
A
V
SS
A
A
A
A
DQ9
TMS
TCK
Note
1. NC/36M, NC/72M, NC/144M, and NC/288M are not connected to the die and can be tied to any voltage level.
Document Number: 001-07160 Rev. *F
Page 3 of 26
CY7C1318CV18
CY7C1320CV18
Pin Definitions
Pin Name
I/O
Pin Description
DQ
Input Output- Data Input Output Signals. Inputs are sampled on the rising edge of K and K clocks during valid write
Synchronous operations. These pins drive out the requested data during a read operation. Valid data is driven out on
the rising edge of both the C and C clocks during read operations or K and K when in single clock mode.
[x:0]
When read access is deselected, Q
are automatically tristated.
[x:0]
CY7C1318CV18 − DQ
CY7C1320CV18 − DQ
[17:0]
[35:0]
LD
Input-
Synchronous Load. This input is brought LOW when a bus cycle sequence is defined. This definition
Synchronous includes address and read/write direction. All transactions operate on a burst of 2 data.
BWS ,
Input-
Byte Write Select 0, 1, 2, and 3 − Active LOW. Sampled on the rising edge of the K and K clocks during
0
BWS ,
Synchronous write operations. Used to select which byte is written into the device during the current portion of the Write
1
BWS ,
operations. Bytes not written remain unaltered.
2
BWS
CY7C1318CV18 − BWS controls D
and BWS controls D
[8:0] [17:9].
3
0
1
CY7C1320CV18 − BWS controls D
, BWS controls D
, BWS controls D
and BWS controls
0
[8:0]
1
[17:9]
2
[26:18]
3
D
.
[35:27]
All the Byte Write Selects are sampled on the same edge as the data. Deselecting a Byte Write Select
ignores the corresponding byte of data and it is not written into the device.
A, A0
Input-
Address Inputs. These address inputs are multiplexed for both read and write operations. Internally, the
Synchronous device is organized as 1M x 18 (2 arrays each of 512K x 18) for CY7C1318CV18, and 512K x 36 (2 arrays
each of 256K x 36) for CY7C1320CV18.
CY7C1318CV18 – A0 is the input to the burst counter. These are incremented internally in a linear fashion.
20 address inputs are needed to access the entire memory array.
CY7C1320CV18 – A0 is the input to the burst counter. These are incremented internally in a linear fashion.
19 address inputs are needed to access the entire memory array. All the address inputs are ignored when
the appropriate port is deselected.
R/W
C
Input-
Synchronous Read/Write Input. When LD is LOW, this input designates the access type (read when
Synchronous R/W is HIGH, write when R/W is LOW) for the loaded address. R/W must meet the setup and hold times
around the edge of K.
Input Clock Positive Input Clock for Output Data. C is used in conjunction with C to clock out the read data from
the device. C and C can be used together to deskew the flight times of various devices on the board back
C
Input Clock Negative Input Clock for Output Data. C is used in conjunction with C to clock out the read data from
the device. C and C can be used together to deskew the flight times of various devices on the board back
K
Input Clock Positive Input Clock Input. The rising edge of K is used to capture synchronous inputs to the device
and to drive out data through Q
edge of K.
when in single clock mode. All accesses are initiated on the rising
[x:0]
K
Input Clock Negative Input Clock Input. K is used to capture synchronous data being presented to the device and
to drive out data through Q when in single clock mode.
[x:0]
CQ
Output Clock CQ Referenced with Respect to C. This is a free running clock and is synchronized to the input clock
for output data (C) of the DDR II. In single clock mode, CQ is generated with respect to K. The timing for
CQ
ZQ
Output Clock CQ Referenced with Respect to C. This is a free running clock and is synchronized to the input clock
for output data (C) of the DDR II. In single clock mode, CQ is generated with respect to K. The timing for
Input
Output Impedance Matching Input. This input is used to tune the device outputs to the system data bus
impedance. CQ, CQ, and Q output impedance are set to 0.2 x RQ, where RQ is a resistor connected
[x:0]
between ZQ and ground. Alternatively, this pin can be connected directly to V
, which enables the
DDQ
minimum impedance mode. This pin cannot be connected directly to GND or left unconnected.
Document Number: 001-07160 Rev. *F
Page 4 of 26
CY7C1318CV18
CY7C1320CV18
Pin Definitions (continued)
Pin Name
I/O
Pin Description
DOFF
Input
DLL Turn Off − Active LOW. Connecting this pin to ground turns off the DLL inside the device. The timing
in the DLL turned off operation is different from that listed in this data sheet. For normal operation, this
pin can be connected to a pull up through a 10 KΩ or less pull up resistor. The device behaves in DDR I
mode when the DLL is turned off. In this mode, the device can be operated at a frequency of up to 167
MHz with DDR I timing.
TDO
Output
Input
Input
Input
N/A
TDO for JTAG.
TCK
TCK Pin for JTAG.
TDI
TDI Pin for JTAG.
TMS
TMS Pin for JTAG.
NC
Not Connected to the Die. Can be tied to any voltage level.
Not Connected to the Die. Can be tied to any voltage level.
Not Connected to the Die. Can be tied to any voltage level.
Not Connected to the Die. Can be tied to any voltage level.
Not Connected to the Die. Can be tied to any voltage level.
Reference Voltage Input. Static input used to set the reference level for HSTL inputs, outputs, and AC
NC/36M
NC/72M
NC/144M
NC/288M
N/A
N/A
N/A
N/A
V
Input-
REF
Reference measurement points.
V
V
V
Power Supply Power Supply Inputs to the Core of the Device.
DD
Ground
Ground for the Device.
SS
Power Supply Power Supply Inputs for the Outputs of the Device.
DDQ
Document Number: 001-07160 Rev. *F
Page 5 of 26
CY7C1318CV18
CY7C1320CV18
subsequent rising edge of the negative input clock (K) the infor-
Functional Overview
mation presented to D
register, provided BWS
is also stored into the write data
are both asserted active. The 36 bits
[17:0]
The CY7C1318CV18, and CY7C1320CV18 are synchronous
pipelined Burst SRAMs equipped with a DDR interface, which
operates with a read latency of one and half cycles when DOFF
pin is tied HIGH. When DOFF pin is set LOW or connected to
[1:0]
of data are then written into the memory array at the specified
location. Write accesses can be initiated on every rising edge of
the positive input clock (K). This pipelines the data flow such that
18 bits of data can be transferred into the device on every rising
edge of the input clocks (K and K).
V
the device behaves in DDR I mode with a read latency of
SS
one clock cycle.
When Write access is deselected, the device ignores all inputs
after the pending write operations are completed.
Accesses are initiated on the rising edge of the positive input
clock (K). All synchronous input timing is referenced from the
rising edge of the input clocks (K and K) and all output timing is
referenced to the rising edge of the output clocks (C/C, or K/K
when in single clock mode).
Byte Write Operations
Byte write operations are supported by the CY7C1318CV18. A
write operation is initiated as described in the Write Operations
All synchronous data inputs (D
) pass through input registers
[x:0]
section. The bytes that are written are determined by BWS and
controlled by the rising edge of the input clocks (K and K). All
synchronous data outputs (Q ) pass through output registers
0
BWS , which are sampled with each set of 18-bit data words.
1
[x:0]
Asserting the appropriate Byte Write Select input during the data
portion of a write latches the data being presented and writes it
into the device. Deasserting the Byte Write Select input during
the data portion of a write enables the data stored in the device
for that byte to remain unaltered. This feature can be used to
simplify read/modify/write operations to a byte write operation.
controlled by the rising edge of the output clocks (C/C, or K/K
when in single-clock mode).
All synchronous control (R/W, LD, BWS
) inputs pass through
[0:X]
input registers controlled by the rising edge of the input clock (K).
CY7C1318CV18 is described in the following sections. The
same basic descriptions apply to CY7C1320CV18.
Single Clock Mode
Read Operations
The CY7C1318CV18 can be used with a single clock that
controls both the input and output registers. In this mode the
device recognizes only a single pair of input clocks (K and K) that
control both the input and output registers. This operation is
identical to the operation if the device had zero skew between
the K/K and C/C clocks. All timing parameters remain the same
in this mode. To use this mode of operation, tie C and C HIGH at
power on. This function is a strap option and not alterable during
device operation.
The CY7C1318CV18 is organized internally as two arrays of
512K x 18. Accesses are completed in a burst of two sequential
18-bit data words. Read operations are initiated by asserting
R/W HIGH and LD LOW at the rising edge of the positive input
clock (K). The address presented to address inputs is stored in
the read address register and the least significant bit of the
address is presented to the burst counter. The burst counter
increments the address in a linear fashion. Following the next K
clock rise, the corresponding 18-bit word of data from this
DDR Operation
address location is driven onto Q
, using C as the output
[17:0]
timing reference. On the subsequent rising edge of C the next
18-bit data word from the address location generated by the
The CY7C1318CV18 enables high-performance operation
through high clock frequencies (achieved through pipelining) and
double data rate mode of operation. The CY7C1318CV18
requires a single No Operation (NOP) cycle when transitioning
from a read to a write cycle. At higher frequencies, some appli-
cations may require a second NOP cycle to avoid contention.
burst counter is driven onto Q
. The requested data is valid
[17:0]
0.45 ns from the rising edge of the output clock (C or C, or K and
K when in single clock mode, 200 MHz and 250 MHz device). To
maintain the internal logic, each read access must be allowed to
complete. Read accesses can be initiated on every rising edge
of the positive input clock (K).
If a read occurs after a write cycle, address and data for the write
are stored in registers. The write information must be stored
because the SRAM cannot perform the last word write to the
array without conflicting with the read. The data stays in this
register until the next write cycle occurs. On the first write cycle
after the read(s), the stored data from the earlier write is written
into the SRAM array. This is called a posted write.
The CY7C1318CV18 first completes the pending read transac-
tions, when read access is deselected. Synchronous internal
circuitry automatically tristates the output following the next rising
edge of the positive output clock (C). This enables a seamless
transition between devices without the insertion of wait states in
a depth expanded memory.
If a read is performed on the same address on which a write is
performed in the previous cycle, the SRAM reads out the most
current data. The SRAM does this by bypassing the memory
array and reading the data from the registers.
Write Operations
Write operations are initiated by asserting R/W LOW and LD
LOW at the rising edge of the positive input clock (K). The
address presented to address inputs is stored in the write
address register and the least significant bit of the address is
presented to the burst counter. The burst counter increments the
address in a linear fashion. On the following K clock rise the data
Depth Expansion
Depth expansion requires replicating the LD control signal for
each bank. All other control signals can be common between
banks as appropriate.
presented to D
is latched and stored into the 18-bit write
[17:0]
data register, provided BWS
are both asserted active. On the
[1:0]
Document Number: 001-07160 Rev. *F
Page 6 of 26
CY7C1318CV18
CY7C1320CV18
Programmable Impedance
DLL
An external resistor, RQ, must be connected between the ZQ pin
These chips use a Delay Lock Loop (DLL) that is designed to
function between 120 MHz and the specified maximum clock
frequency. During power up, when the DOFF is tied HIGH, the
DLL is locked after 1024 cycles of stable clock. The DLL can also
be reset by slowing or stopping the input clocks K and K for a
minimum of 30 ns. However, it is not necessary to reset the DLL
to lock it to the desired frequency. The DLL automatically locks
1024 clock cycles after a stable clock is presented. The DLL may
be disabled by applying ground to the DOFF pin. When the DLL
is turned off, the device behaves in DDR I mode (with one cycle
latency and a longer access time). For information refer to the
application note DLL Considerations in QDRII™/DDRII.
on the SRAM and V to enable the SRAM to adjust its output
SS
driver impedance. The value of RQ must be 5x the value of the
intended line impedance driven by the SRAM. The allowable
range of RQ to guarantee impedance matching with a tolerance
of ±15% is between 175Ω and 350Ω, with V
= 1.5V. The
DDQ
output impedance is adjusted every 1024 cycles at power up to
account for drifts in supply voltage and temperature.
Echo Clocks
Echo clocks are provided on the DDR II to simplify data capture
on high speed systems. Two echo clocks are generated by the
DDR II. CQ is referenced with respect to C and CQ is referenced
with respect to C. These are free running clocks and are synchro-
nized to the output clock of the DDR II. In the single clock mode,
CQ is generated with respect to K and CQ is generated with
Application Example
Figure 1 shows two DDR II used in an application.
Figure 1. Application Example
R = 250ohms
R = 250ohms
SRAM#2
SRAM#1
ZQ
ZQ
DQ
A
DQ
A
CQ/CQ#
LD# R/W# C C# K K#
CQ/CQ#
LD# R/W# C C#
K
K#
DQ
Addresses
Cycle Start#
R/W#
Return CLK
Source CLK
Return CLK#
Source CLK#
BUS
MASTER
(CPU
or
Vterm = 0.75V
R = 50ohms
Vterm = 0.75V
ASIC)
Echo Clock1/Echo Clock#1
Echo Clock2/Echo Clock#2
Document Number: 001-07160 Rev. *F
Page 7 of 26
CY7C1318CV18
CY7C1320CV18
Truth Table
The truth table for the CY7C1318CV18, and CY7C1320CV18 follows.
Operation
K
LD
R/W
DQ
DQ
Write Cycle:
Load address; wait one cycle;
L-H
L
L
D(A1) at K(t + 1) ↑ D(A2) at K(t + 1) ↑
input write data on consecutive K and K rising edges.
Read Cycle:
Load address; wait one and a half cycle;
read data on consecutive C and C rising edges.
L-H
L
H
Q(A1) at C(t + 1)↑ Q(A2) at C(t + 2) ↑
NOP: No Operation
L-H
H
X
X
X
High-Z
High-Z
Standby: Clock Stopped
Stopped
Previous State
Previous State
Burst Address Table
(CY7C1318CV18, CY7C1320CV18)
First Address (External)
Second Address (Internal)
X..X0
X..X1
X..X1
X..X0
Write Cycle Descriptions
The write cycle description table for CY7C1318CV18 follows.
BWS
BWS
K
Comments
During the data portion of a write sequence :
Both bytes (D ) are written into the device.
K
0
1
L
L
L–H
–
[17:0]
L
L
L
H
H
L
–
L–H
–
L-H During the data portion of a write sequence :
Both bytes (D ) are written into the device.
[17:0]
–
During the data portion of a write sequence :
Only the lower byte (D ) is written into the device, D
remains unaltered.
remains unaltered.
remains unaltered.
remains unaltered.
[8:0]
[17:9]
L
L–H During the data portion of a write sequence :
Only the lower byte (D ) is written into the device, D
[8:0]
[17:9]
H
H
L–H
–
–
During the data portion of a write sequence :
Only the upper byte (D ) is written into the device, D
[17:9]
[8:0]
L
L–H During the data portion of a write sequence :
Only the upper byte (D ) is written into the device, D
[17:9]
[8:0]
H
H
H
H
L–H
–
–
No data is written into the devices during this portion of a write operation.
L–H No data is written into the devices during this portion of a write operation.
Notes
2. X = “Don’t Care,” H = Logic HIGH, L = Logic LOW, ↑ represents rising edge.
3. Device powers up deselected with the outputs in a tristate condition.
4. On CY7C1318CV18 and CY7C1320CV18, “A1” represents address location latched by the devices when transaction was initiated and “A2” represents the addresses
sequence in the burst.
5. “t” represents the cycle at which a read/write operation is started. t + 1 and t + 2 are the first and second clock cycles succeeding the “t” clock cycle.
6. Data inputs are registered at K and K rising edges. Data outputs are delivered on C and C rising edges, except when in single clock mode.
7. It is recommended that K = K and C = C = HIGH when clock is stopped. This is not essential, but permits most rapid restart by overcoming transmission line charging
symmetrically.
8. Is based on a write cycle that was initiated in accordance with the Write Cycle Descriptions table. BWS , BWS , BWS , and BWS can be altered on different portions
0
1
2
3
of a write cycle, as long as the setup and hold requirements are achieved.
Document Number: 001-07160 Rev. *F
Page 8 of 26
CY7C1318CV18
CY7C1320CV18
Write Cycle Descriptions
The write cycle description table for CY7C1320CV18 follows.
BWS
BWS
BWS
BWS
3
K
K
Comments
0
1
2
L
L
L
L
L–H
–
During the data portion of a write sequence, all four bytes (D
the device.
) are written into
) are written into
[35:0]
L
L
L
H
H
L
L
H
H
H
H
L
L
H
H
H
H
H
H
L
–
L–H
–
L–H During the data portion of a write sequence, all four bytes (D
the device.
[35:0]
–
During the data portion of a write sequence, only the lower byte (D
) is written
) is written
[8:0]
[8:0]
into the device. D
remains unaltered.
[35:9]
L
L–H During the data portion of a write sequence, only the lower byte (D
into the device. D remains unaltered.
[35:9]
H
H
H
H
H
H
L–H
–
–
During the data portion of a write sequence, only the byte (D
) is written into
) is written into
[17:9]
the device. D
and D
remains unaltered.
[8:0]
[35:18]
L
L–H During the data portion of a write sequence, only the byte (D
the device. D and D remains unaltered.
[17:9]
[8:0]
[35:18]
H
H
H
H
L–H
–
–
During the data portion of a write sequence, only the byte (D
) is written into
) is written into
) is written into
) is written into
[26:18]
[26:18]
[35:27]
[35:27]
the device. D
and D
remains unaltered.
[17:0]
[35:27]
L
L–H During the data portion of a write sequence, only the byte (D
the device. D and D remains unaltered.
[17:0]
[35:27]
H
H
L–H
–
–
During the data portion of a write sequence, only the byte (D
the device. D remains unaltered.
[26:0]
L
L–H During the data portion of a write sequence, only the byte (D
the device. D remains unaltered.
[26:0]
H
H
H
H
H
H
H
H
L–H
–
–
No data is written into the device during this portion of a write operation.
L–H No data is written into the device during this portion of a write operation.
Document Number: 001-07160 Rev. *F
Page 9 of 26
CY7C1318CV18
CY7C1320CV18
Instruction Register
IEEE 1149.1 Serial Boundary Scan (JTAG)
Three-bit instructions can be serially loaded into the instruction
register. This register is loaded when it is placed between the TDI
page 13. Upon power up, the instruction register is loaded with
the IDCODE instruction. It is also loaded with the IDCODE
instruction if the controller is placed in a reset state, as described
in the previous section.
These SRAMs incorporate a serial boundary scan Test Access
Port (TAP) in the FBGA package. This part is fully compliant with
IEEE Standard #1149.1-2001. The TAP operates using JEDEC
standard 1.8V I/O logic levels.
Disabling the JTAG Feature
It is possible to operate the SRAM without using the JTAG
feature. To disable the TAP controller, TCK must be tied LOW
When the TAP controller is in the Capture-IR state, the two least
significant bits are loaded with a binary “01” pattern to allow for
fault isolation of the board level serial test path.
(V ) to prevent clocking of the device. TDI and TMS are inter-
SS
nally pulled up and may be unconnected. They may alternatively
be connected to V through a pull up resistor. TDO must be left
unconnected. Upon power up, the device comes up in a reset
state, which does not interfere with the operation of the device.
Bypass Register
DD
To save time when serially shifting data through registers, it is
sometimes advantageous to skip certain chips. The bypass
register is a single-bit register that can be placed between TDI
and TDO pins. This enables shifting of data through the SRAM
with minimal delay. The bypass register is set LOW (V ) when
the BYPASS instruction is executed.
Test Access Port—Test Clock
The test clock is used only with the TAP controller. All inputs are
captured on the rising edge of TCK. All outputs are driven from
the falling edge of TCK.
SS
Boundary Scan Register
Test Mode Select (TMS)
The boundary scan register is connected to all of the input and
output pins on the SRAM. Several No Connect (NC) pins are also
included in the scan register to reserve pins for higher density
devices.
The TMS input is used to give commands to the TAP controller
and is sampled on the rising edge of TCK. This pin may be left
unconnected if the TAP is not used. The pin is pulled up inter-
nally, resulting in a logic HIGH level.
The boundary scan register is loaded with the contents of the
RAM input and output ring when the TAP controller is in the
Capture-DR state and is then placed between the TDI and TDO
pins when the controller is moved to the Shift-DR state. The
EXTEST, SAMPLE/PRELOAD, and SAMPLE Z instructions can
be used to capture the contents of the input and output ring.
Test Data-In (TDI)
The TDI pin is used to serially input information into the registers
and can be connected to the input of any of the registers. The
register between TDI and TDO is chosen by the instruction that
is loaded into the TAP instruction register. For information on
loading the instruction register, see the TAP Controller State
unconnected if the TAP is unused in an application. TDI is
connected to the most significant bit (MSB) on any register.
the bits are connected. Each bit corresponds to one of the bumps
on the SRAM package. The MSB of the register is connected to
TDI, and the LSB is connected to TDO.
Identification (ID) Register
Test Data-Out (TDO)
The ID register is loaded with a vendor-specific, 32-bit code
during the Capture-DR state when the IDCODE command is
loaded in the instruction register. The IDCODE is hardwired into
the SRAM and can be shifted out when the TAP controller is in
the Shift-DR state. The ID register has a vendor code and other
The TDO output pin is used to serially clock data out from the
registers. The output is active, depending upon the current state
The output changes on the falling edge of TCK. TDO is
connected to the least significant bit (LSB) of any register.
Performing a TAP Reset
A Reset is performed by forcing TMS HIGH (V ) for five rising
TAP Instruction Set
DD
edges of TCK. This Reset does not affect the operation of the
SRAM and can be performed while the SRAM is operating. At
power up, the TAP is reset internally to ensure that TDO comes
up in a high-Z state.
Eight different instructions are possible with the three-bit
instruction register. All combinations are listed in Instruction
RESERVED and must not be used. The other five instructions
are described in detail below.
TAP Registers
Instructions are loaded into the TAP controller during the Shift-IR
state when the instruction register is placed between TDI and
TDO. During this state, instructions are shifted through the
instruction register through the TDI and TDO pins. To execute
the instruction once it is shifted in, the TAP controller must be
moved into the Update-IR state.
Registers are connected between the TDI and TDO pins to scan
the data in and out of the SRAM test circuitry. Only one register
can be selected at a time through the instruction registers. Data
is serially loaded into the TDI pin on the rising edge of TCK. Data
is output on the TDO pin on the falling edge of TCK.
Document Number: 001-07160 Rev. *F
Page 10 of 26
CY7C1318CV18
CY7C1320CV18
IDCODE
PRELOAD places an initial data pattern at the latched parallel
outputs of the boundary scan register cells before the selection
of another boundary scan test operation.
The IDCODE instruction loads a vendor-specific, 32-bit code into
the instruction register. It also places the instruction register
between the TDI and TDO pins and shifts the IDCODE out of the
device when the TAP controller enters the Shift-DR state. The
IDCODE instruction is loaded into the instruction register at
power up or whenever the TAP controller is supplied a
Test-Logic-Reset state.
The shifting of data for the SAMPLE and PRELOAD phases can
occur concurrently when required, that is, while the data
captured is shifted out, the preloaded data can be shifted in.
BYPASS
When the BYPASS instruction is loaded in the instruction register
and the TAP is placed in a Shift-DR state, the bypass register is
placed between the TDI and TDO pins. The advantage of the
BYPASS instruction is that it shortens the boundary scan path
when multiple devices are connected together on a board.
SAMPLE Z
The SAMPLE Z instruction connects the boundary scan register
between the TDI and TDO pins when the TAP controller is in a
Shift-DR state. The SAMPLE Z command puts the output bus
into a High-Z state until the next command is supplied during the
Update IR state.
EXTEST
The EXTEST instruction drives the preloaded data out through
the system output pins. This instruction also connects the
boundary scan register for serial access between the TDI and
TDO in the Shift-DR controller state.
SAMPLE/PRELOAD
SAMPLE/PRELOAD is a 1149.1 mandatory instruction. When
the SAMPLE/PRELOAD instructions are loaded into the
instruction register and the TAP controller is in the Capture-DR
state, a snapshot of data on the input and output pins is captured
in the boundary scan register.
EXTEST OUTPUT BUS TRISTATE
IEEE Standard 1149.1 mandates that the TAP controller be able
to put the output bus into a tristate mode.
The user must be aware that the TAP controller clock can only
operate at a frequency up to 20 MHz, while the SRAM clock
operates more than an order of magnitude faster. Because there
is a large difference in the clock frequencies, it is possible that
during the Capture-DR state, an input or output undergoes a
transition. The TAP may then try to capture a signal while in
transition (metastable state). This does not harm the device, but
there is no guarantee as to the value that is captured.
Repeatable results may not be possible.
The boundary scan register has a special bit located at bit #47.
When this scan cell, called the “extest output bus tristate,” is
latched into the preload register during the Update-DR state in
the TAP controller, it directly controls the state of the output
(Q-bus) pins, when the EXTEST is entered as the current
instruction. When HIGH, it enables the output buffers to drive the
output bus. When LOW, this bit places the output bus into a
High-Z condition.
To guarantee that the boundary scan register captures the
correct value of a signal, the SRAM signal must be stabilized
long enough to meet the TAP controller's capture setup plus hold
times (t and t ). The SRAM clock input might not be captured
correctly if there is no way in a design to stop (or slow) the clock
during a SAMPLE/PRELOAD instruction. If this is an issue, it is
still possible to capture all other signals and simply ignore the
value of the CK and CK captured in the boundary scan register.
This bit can be set by entering the SAMPLE/PRELOAD or
EXTEST command, and then shifting the desired bit into that cell,
during the Shift-DR state. During Update-DR, the value loaded
into that shift-register cell latches into the preload register. When
the EXTEST instruction is entered, this bit directly controls the
output Q-bus pins. Note that this bit is pre-set HIGH to enable
the output when the device is powered up, and also when the
TAP controller is in the Test-Logic-Reset state.
CS
CH
Once the data is captured, it is possible to shift out the data by
putting the TAP into the Shift-DR state. This places the boundary
scan register between the TDI and TDO pins.
Reserved
These instructions are not implemented but are reserved for
future use. Do not use these instructions.
Document Number: 001-07160 Rev. *F
Page 11 of 26
CY7C1318CV18
CY7C1320CV18
TAP Controller State Diagram
The state diagram for the TAP controller follows.
TEST-LOGIC
1
RESET
0
1
1
1
SELECT
TEST-LOGIC/
SELECT
0
IR-SCAN
IDLE
DR-SCAN
0
0
1
1
CAPTURE-DR
0
CAPTURE-IR
0
0
0
SHIFT-DR
1
SHIFT-IR
1
1
0
1
EXIT1-DR
0
EXIT1-IR
0
0
PAUSE-DR
1
PAUSE-IR
1
0
0
EXIT2-DR
1
EXIT2-IR
1
UPDATE-IR
0
UPDATE-DR
1
1
0
Note
9. The 0/1 next to each state represents the value at TMS at the rising edge of TCK.
Document Number: 001-07160 Rev. *F
Page 12 of 26
CY7C1318CV18
CY7C1320CV18
TAP Controller Block Diagram
0
Bypass Register
2
1
1
1
0
0
0
Selection
TDI
Selection
TDO
Instruction Register
Circuitry
Circuitry
31 30
29
.
.
2
Identification Register
.
106
.
.
.
2
Boundary Scan Register
TCK
TMS
TAP Controller
TAP Electrical Characteristics
Over the Operating Range
Parameter
Description
Output HIGH Voltage
Test Conditions
= −2.0 mA
Min
1.4
1.6
Max
Unit
V
V
V
V
V
V
I
I
I
I
I
V
V
OH1
OH2
OL1
OL2
IH
OH
OH
OL
OL
Output HIGH Voltage
Output LOW Voltage
Output LOW Voltage
Input HIGH Voltage
= −100 μA
= 2.0 mA
0.4
0.2
V
= 100 μA
V
0.65V
V
+ 0.3
V
DD
DD
Input LOW Voltage
–0.3
–5
0.35V
5
V
IL
DD
Input and Output Load Current
GND ≤ V ≤ V
DD
μA
X
I
Notes
10. These characteristics pertain to the TAP inputs (TMS, TCK, TDI and TDO). Parallel load levels are specified in the Electrical Characteristics Table.
11. Overshoot: V (AC) < V + 0.85V (Pulse width less than t /2).
/2), Undershoot: V (AC) > −1.5V (Pulse width less than t
IH
DDQ
CYC
IL
CYC
12. All Voltage referenced to Ground.
Document Number: 001-07160 Rev. *F
Page 13 of 26
CY7C1318CV18
CY7C1320CV18
TAP AC Switching Characteristics
Over the Operating Range
Parameter
Description
Min
Max
Unit
ns
t
t
t
t
TCK Clock Cycle Time
TCK Clock Frequency
TCK Clock HIGH
50
TCYC
TF
20
MHz
ns
20
20
TH
TCK Clock LOW
ns
TL
Setup Times
t
t
t
TMS Setup to TCK Clock Rise
TDI Setup to TCK Clock Rise
Capture Setup to TCK Rise
5
5
5
ns
ns
ns
TMSS
TDIS
CS
Hold Times
t
t
t
TMS Hold after TCK Clock Rise
TDI Hold after Clock Rise
5
5
5
ns
ns
ns
TMSH
TDIH
CH
Capture Hold after Clock Rise
Output Times
t
t
TCK Clock LOW to TDO Valid
TCK Clock LOW to TDO Invalid
10
ns
ns
TDOV
TDOX
0
TAP Timing and Test Conditions
Figure 2 shows the TAP timing and test conditions.
Figure 2. TAP Timing and Test Conditions
0.9V
ALL INPUT PULSES
1.8V
50Ω
0.9V
TDO
0V
Z = 50
Ω
0
C = 20 pF
L
t
TL
t
TH
GND
(a)
Test Clock
TCK
t
TCYC
t
TMSH
t
TMSS
Test Mode Select
TMS
t
TDIS
t
TDIH
Test Data In
TDI
Test Data Out
TDO
t
TDOV
t
TDOX
Notes
13. t and t refer to the setup and hold time requirements of latching data from the boundary scan register.
CS
CH
14. Test conditions are specified using the load in TAP AC Test Conditions. t /t = 1 ns.
R
F
Document Number: 001-07160 Rev. *F
Page 14 of 26
|