CY7C1316BV18, CY7C1916BV18 CY7C1318BV18, CY7C1320BV18

IDCODE

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.

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.

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.

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.

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 (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.

After 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 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 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.

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.

EXTEST OUTPUT BUS TRI-STATE

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

The boundary scan register has a special bit located at bit #47. When this scan cell, called the “extest output bus tri-state,” 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.

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.

Reserved

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

Document Number: 38-05621 Rev. *D

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Cypress CY7C1320BV18, CY7C1318BV18, CY7C1316BV18, CY7C1916BV18 manual Idcode
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CY7C1316BV18, CY7C1916BV18, CY7C1320BV18, CY7C1318BV18 specifications

The Cypress CY7C1318BV18, CY7C1320BV18, CY7C1916BV18, and CY7C1316BV18 are advanced synchronous static RAM (SRAM) devices designed to meet the high-performance requirements of modern computing systems. Offering a blend of high speed, low power consumption, and large storage capacities, these chips are widely utilized in applications such as networking equipment, telecommunications, and high-speed data processing.

The CY7C1318BV18 is a 2 Megabit SRAM that operates at a 2.5V supply voltage. It features a fast access time of 10ns, making it an excellent choice for systems that require rapid data retrieval. Its asynchronous interface simplifies integration into a wide range of devices. In terms of power efficiency, the CY7C1318BV18 has a low operating current, ensuring that it can be utilized in battery-powered applications without significantly draining power.

Similarly, the CY7C1320BV18 offers a larger 256 Kbit capacity while maintaining the same low-voltage operation and performance characteristics. This chip also features a synchronous interface, supporting high-speed data transfer rates that are ideal for networking and communication devices. The CY7C1320BV18's features include deep-write operation capabilities, enhancing its performance in write-intensive applications.

The CY7C1916BV18 takes performance a step further with its 32 Megabit capacity, suitable for applications requiring extensive memory resources. This device also supports advanced functions such as burst read modes, allowing for faster sequential data access. With its low-latency performance, the CY7C1916BV18 is an excellent choice for applications like digital signal processing and real-time data analysis.

Lastly, the CY7C1316BV18 is another variant offering 1 Megabit of storage. It combines high-speed functionality with low power usage, supporting a wide range of applications including consumer electronics and automotive systems. Its robust design ensures reliability under varying environmental conditions.

All of these SRAM devices incorporate Cypress’s advanced semiconductor technology, providing a combination of speed, efficiency, and reliability. They are available in various package options, which facilitate easy integration into diverse system designs. Overall, the Cypress CY7C1318BV18, CY7C1320BV18, CY7C1916BV18, and CY7C1316BV18 exemplify the company’s commitment to delivering high-quality memory solutions that cater to the evolving needs of the electronic industry.
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