Cypress CY7C1302DV25 manual Sample Z

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CY7C1302DV25

is loaded into the instruction register upon power-up or whenever the TAP controller is given a test logic reset state.

SAMPLE Z

The SAMPLE Z instruction causes the boundary scan register to be connected 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 given during the “Update IR” 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 inputs and output pins is captured in the boundary scan register.

The user must be aware that the TAP controller clock can only operate at a frequency up to 10 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 will undergo a transition. The TAP may then try to capture a signal while in transition (metastable state). This will not harm the device, but there is no guarantee as to the value that will be captured. Repeatable results may not be possible.

To guarantee that the boundary scan register will capture the correct value of a signal, the SRAM signal must be stabilized long enough to meet the TAP controller's capture set-up plus hold times (tCS and tCH). 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.

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.

PRELOAD allows an initial data pattern to be placed at the latched parallel outputs of the boundary scan register cells prior to the selection of another boundary scan test operation.

The shifting of data for the SAMPLE and PRELOAD phases can occur concurrently when required—that is, while 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.

EXTEST

The EXTEST instruction enables the preloaded data to be driven out through the system output pins. This instruction also selects the boundary scan register to be connected for serial access between the TDI and TDO in the shift-DR controller state.

EXTEST Output Bus Three-state

IEEE Standard 1149.1 mandates that the TAP controller be able to put the output bus into a three-state mode.

The boundary scan register has a special bit located at bit #47. When this scan cell, called the “extest output bus three-state”, is latched into the preload register during the “Update-DR” state in the TAP controller, it will directly control the state of the output (Q-bus) pins, when the EXTEST is entered as the current instruction. When HIGH, it will enable the output buffers to drive the output bus. When LOW, this bit will place the output bus into a High-Z condition.

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 will latch into the preload register. When the EXTEST instruction is entered, this bit will directly control 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.

Reserved

These instructions are not implemented but are reserved for future use. Do not use these instructions.

Document #: 38-05625 Rev. *A

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Contents Functional Description FeaturesConfigurations Logic Block Diagram CY7C1302DV25Selection Guide Pin Configuration Ball Fbga 13 x 15 x 1.4 mm PinoutPin Definitions Introduction Application Example1 Operation Write Cycle Descriptions 2,8Comments Ieee 1149.1 Serial Boundary Scan Jtag Sample Z EXIT2-IR UPDATE-DR UPDATE-IR TAP Controller State Diagram9Set-up Times TAP Controller Block DiagramParameter Description Test Conditions Min Max Unit Parameter Description Min Max UnitIdentification Register Definitions TAP Timing and Test Conditions12Instruction Code Description Scan Register SizesInstruction Codes Register Name Bit SizeBit # Bump ID Boundary Scan OrderParameter Description Test Conditions Min Typ Max Unit Range Ambient Temperature TMaximum Ratings Operating RangeAC Test Loads and Waveforms Switching Characteristics Over the Operating RangeThermal Resistance20 Capacitance20Rise to High-Z Active to High-Z 23 Switching Characteristics Over the Operating RangeClock Rise or K/K in single clock mode to Data Valid Clock Rise Active to ActiveWrite Read NOP Switching Waveforms25, 26CY7C1302DV25-167BZXI Package DiagramOrdering Information CY7C1302DV25-167BZXCDocument History Issue Date Orig. Description of Change

CY7C1302DV25 specifications

The Cypress CY7C1302DV25 is a high-performance static random-access memory (SRAM) device designed to meet the demanding requirements of modern electronic systems. It operates with a supply voltage of 2.5V, making it ideal for battery-powered applications, while offering up to 1 Mbit of memory storage. This device is widely used in various applications, including telecommunications, networking, and industrial automation, due to its speed, reliability, and efficiency.

One of the main features of the CY7C1302DV25 is its fast access time, which reaches as low as 10 nanoseconds. This rapid access allows for quicker data retrieval and processing, enhancing overall system performance. The device supports asynchronous read and write operations, providing flexibility in how data is managed and utilized within a system.

The CY7C1302DV25 has a rich set of functionalities that include word and byte write modes, allowing for efficient data manipulation. Its dual-port architecture enables simultaneous read and write operations, making it suitable for applications requiring high data throughput. This feature is particularly beneficial in systems where multiple devices need to access or update memory concurrently.

From a technological standpoint, the CY7C1302DV25 utilizes advanced CMOS technology, which not only contributes to its low power consumption but also enhances its durability and reliability. Lower power consumption is a crucial aspect for many applications, especially in portable devices, where battery life is a significant concern. The CY7C1302DV25 also incorporates built-in write protection, ensuring data integrity and security against unintentional writes during operation.

In terms of physical characteristics, the device comes in a compact 44-pin Thin Quad Flat No-lead (TQFN) package, making it suitable for space-constrained designs. Its small footprint allows for integration into densely packed circuit boards, providing manufacturers with flexibility in design.

Overall, the Cypress CY7C1302DV25 is a versatile and efficient SRAM solution that combines speed, low power consumption, and robust features, making it an excellent choice for a wide range of applications in the ever-evolving landscape of electronics. Its reliability and advanced specifications position it as a dependable memory solution for both current and future technologies.
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