Cypress CY7C1382C, CY7C1380C Bypass Register, Boundary Scan Register, Identification ID Register

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CY7C1380C

CY7C1382C

TDI and TDO balls as shown in the Tap Controller Block Diagram. 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.

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 data path.

Bypass Register

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 the TDI and TDO balls. This allows data to be shifted through the SRAM with minimal delay. The bypass register is set LOW (VSS) when the BYPASS instruction is executed.

Boundary Scan Register

The boundary scan register is connected to all the input and bidirectional balls on the SRAM. The SRAM has a 75-bit-long register.

The boundary scan register is loaded with the contents of the RAM I/O ring when the TAP controller is in the Capture-DR state and is then placed between the TDI and TDO balls 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 I/O ring.

The Boundary Scan Order tables show the order in which 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

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 information described in the Identification Register Definitions table.

TAP Instruction Set

Overview

Eight different instructions are possible with the three bit instruction register. All combinations are listed in the Instruction Codes table. Three of these instructions are listed as RESERVED and should not be used. The other five instruc- tions are described in detail below.

The TAP controller used in this SRAM is not fully compliant to the 1149.1 convention because some of the mandatory 1149.1 instructions are not fully implemented.

The TAP controller cannot be used to load address data or control signals into the SRAM and cannot preload the I/O buffers. The SRAM does not implement the 1149.1 commands EXTEST or INTEST or the PRELOAD portion of SAMPLE/PRELOAD; rather, it performs a capture of the I/O ring when these instructions are executed.

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 balls.

To execute the instruction once it is shifted in, the TAP controller needs to be moved into the Update-IR state.

EXTEST

EXTEST is a mandatory 1149.1 instruction which is to be executed whenever the instruction register is loaded with all 0s. EXTEST is not implemented in this SRAM TAP controller, and therefore this device is not compliant to 1149.1. The TAP controller does recognize an all-0 instruction.

When an EXTEST instruction is loaded into the instruction register, the SRAM responds as if a SAMPLE/PRELOAD instruction has been loaded. There is one difference between the two instructions. Unlike the SAMPLE/PRELOAD instruction, EXTEST places the SRAM outputs in a High-Z state.

IDCODE

The IDCODE instruction causes a vendor-specific, 32-bit code to be loaded into the instruction register. It also places the instruction register between the TDI and TDO balls and allows the IDCODE to be shifted out of the device when the TAP controller enters the Shift-DR state.

The IDCODE instruction 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 balls when the TAP controller is in a Shift-DR state. It also places all SRAM outputs into a High-Z state.

SAMPLE/PRELOAD

SAMPLE/PRELOAD is a 1149.1 mandatory instruction. The PRELOAD portion of this instruction is not implemented, so the device TAP controller is not fully 1149.1 compliant.

When the SAMPLE/PRELOAD instruction is loaded into the instruction register and the TAP controller is in the Capture-DR state, a snapshot of data on the inputs and bidirectional balls 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 setup plus hold time (tCS plus 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 CLK 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 balls.

Document #: 38-05237 Rev. *D

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Contents Features Functional Description1Selection Guide 250 MHz 225 MHz 200 MHz 167 MHz 133 MHz UnitLogic Block Diagram CY7C1380C 512K x Logic Block Diagram CY7C1382C 1M xCY7C1380C 512K X Pin ConfigurationsCY7C1382C 1M x NC / 72M NC / 36M CY7C1382C 512K xNC / 288M NC / 72MCY7C1380C-Pin Definitions Tqfp BGAPower supply inputs to the core of the de Address Strobe from Processor, sampledOn the rising edge of CLK, active LOW. When Address Strobe from Controller, sampled onPower supply for the I/O circuitry Selects Burst Order . When tied to GNDGround for the I/O circuitry Serial data-out to the Jtag circuit . DeliversCY7C1382CPin Definitions Rising edge of CLK, active LOW . When asserted ZZ sleep Input, active High . When assertedPower supply inputs to the core of the device Address Strobe from Processor, sampled onSerial data-out to the Jtag circuit . Delivers data Single Read Accesses Functional OverviewInterleaved Burst Address Table Mode = Floating or VDD ZZ Mode Electrical CharacteristicsAddress CE2 Adsp Adsc ADV Write CLKTruth Table for Read/Write5 CLK Adsp Adsc ADV WriteFunction CY7C1380C BWETAP Controller Block Diagram TAP Controller State Diagram Ieee 1149.1 Serial Boundary Scan JtagBypass Register Boundary Scan RegisterIdentification ID Register TAP Instruction SetTAP AC Switching Characteristics Over the operating Range9 TAP Timing5V TAP AC Output Load Equivalent 3V TAP AC Test ConditionsParameter Description Test Conditions MIN MAX Units Scan Register Sizes Identification Register DefinitionsIdentification Codes Ball BGA Boundary Scan Order CY7C1380C 512K x Ball BGA Boundary Scan Order CY7C1382C 1M x Ball fBGA Boundary Scan Order CY7C1380C 512K x A10F10 G10 J10Ball fBGA Boundary Scan Order CY7C1382C 1M x Electrical Characteristics Over the Operating Range12 Maximum RatingsOperating Range Ambient RangeThermal Resistance14 CapacitanceParameter Description Test Conditions FBGA Unit3V I/O Test Load AC Test Loads and Waveforms5V I/O Test Load Switching Characteristics Over the Operating Range19 Min Max UnitSwitching Waveforms Read Cycle Timing21Write Cycle Timing21 Read/Write Cycle Timing21, 23 CLZZZ Mode Timing 25 CY7C1382C-250AC CY7C1380C-250BGC Ordering InformationCY7C1382C-167AI CY7C1380C-167BGI Package Diagrams Pin Thin Plastic Quad Flatpack 14 x 20 x 1.4 mm A101Lead Pbga 14 x 22 x 2.4 mm BG119 Package Diagrams Document History Issue Date Orig. Description of ChangeREV ECN no
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