Question 1

MAX7000 series overview (technology, scale, supply) Which statement best summarizes key characteristics available across the Altera MAX 7000 series?

Accepted Answer

Introduction / Context: The MAX7000 family (including S/A/AE variants) is a widely used CPLD line known for in-system programmability and EEPROM configuration. Recognizing its process technology, scaling across densities, and voltage options helps in selecting the right device for legacy and mixed-voltage designs. Given Data / Assumptions: MAX7000 devices use EEPROM (E2PROM) technology for nonvolatile configuration. The family spans multiple densities, reflected in a range of LAB counts. Different sub-families support various supply voltages, commonly from 5 V down to 3.3 V and 2.5 V offerings. Concept / Approach: Option (a) identifies the nonvolatile E2PROM configuration process. Option (b) summarizes the scalable architecture with a practical range of LAB counts used across members of the family. Option (c) reflects that the series includes variants supporting core/IO voltages across typical legacy (5 V) and modern (3.3/2.5 V) systems. Collectively, these statements are accurate for the broader MAX7000 line, making “all of the above” correct. Step-by-Step Solution: Check configuration tech: EEPROM/E2PROM → nonvolatile.Review density range: small to moderate devices → a few to many LABs (for example, single-digit to mid-teens).Confirm voltage variants: parts exist for 5 V, 3.3 V, and 2.5 V systems depending on subfamily.Therefore, select “all of the above.” Verification / Alternative check: Family summaries in vendor catalogs list E2PROM configuration, multiple density options (LAB counts), and supply options spanning 2.5–5 V across MAX7000 sub-lines. Why Other Options Are Wrong: Each single statement captures only part of the story; the comprehensive answer is “all of the above.” Common Pitfalls: Assuming every individual part in the family supports all voltages; voltage options vary by sub-family, so check the exact part number when designing power rails. Final Answer: all of the above

Question 2

JTAG-based test methods Which of the following test procedures specifically uses the IEEE 1149.1 JTAG standard?

Accepted Answer

Introduction / Context: JTAG (IEEE 1149.1) defines a standard interface and architecture for testing and debugging integrated circuits. Understanding which board-level test techniques rely on JTAG helps engineers plan for design-for-test (DFT), select connectors, and script automated tests in manufacturing. Given Data / Assumptions: Boundary-scan architecture inserts scan cells at I/O pins of compliant devices. The JTAG TAP (Test Access Port) provides standardized pins: TCK, TMS, TDI, TDO (and optionally TRST). EXTEST is a JTAG instruction used within the boundary-scan procedure. Concept / Approach: Among the options, “Boundary scan” is the board-level test methodology explicitly defined by IEEE 1149.1. It enables interconnect testing without physical probes by shifting test data into boundary cells and capturing responses. “EXTEST” is an instruction within boundary scan (not a procedure by itself). Bed-of-nails and flying-probe are physical probing methods, independent of JTAG, although they may be used in combination with JTAG on some lines. Step-by-Step Solution: Identify which option names a standardized JTAG method: Boundary scan.Recognize EXTEST as a JTAG instruction, not the overarching procedure.Exclude physical probing methods (bed-of-nails, flying probe) as non-JTAG by definition.Select “Boundary scan.” Verification / Alternative check: IEEE 1149.1 documentation describes boundary-scan test logic, instruction register, and opcodes (including EXTEST), confirming that boundary scan is the JTAG-based test methodology. Why Other Options Are Wrong: Bed-of-nails / Flying probe: Mechanical probing fixtures; not defined by the JTAG standard. EXTEST: A single JTAG instruction used during boundary-scan tests, not the procedure name. Common Pitfalls: Conflating a specific JTAG opcode (EXTEST) with the overall standardized method (boundary scan). Also, assuming physical ICT/FP testing equals JTAG testing—many boards use both but they are distinct techniques. Final Answer: Boundary scan

Question 3

Microprocessors and DSPs vs. general digital systems What is the defining difference that sets microprocessor/DSP-based systems apart from other digital systems?

Accepted Answer

Introduction / Context: Digital electronics spans a spectrum from fixed-function combinational/sequential logic to fully programmable computing cores. The key distinction for microprocessor and digital signal processor (DSP) systems is not merely speed or technology node, but the presence of a stored program that dictates behavior cycle by cycle. Given Data / Assumptions: A “microprocessor/DSP system” executes instructions fetched from memory. “Other digital systems” may be hardwired logic with no instruction stream. Performance (speed) is not the primary defining characteristic in this question. Concept / Approach: Microprocessors and DSPs are general-purpose or domain-focused compute engines. They read instructions (opcodes) and data from memory, execute them in sequence (possibly with branching), and thus their function can be changed by altering the program. By contrast, fixed digital logic implements behavior directly in gates and flip-flops; altering behavior requires modifying the hardware or configuration bits (in PLDs/FPGAs), not an instruction stream. Step-by-Step Solution: Identify the hallmark of a CPU/DSP: stored-program execution.Note that speed is incidental; many non-CPU digital ASICs can be faster.Therefore, the defining difference is the programmed sequence of instructions executed by the microprocessor/DSP.Map to options: the statement explicitly mentioning the microprocessor and a programmed sequence is correct. Verification / Alternative check: Consider reprogrammability: swapping firmware changes system behavior without changing hardware, which is unique to microprocessor/DSP architectures compared to fixed logic. Why Other Options Are Wrong: A: Many digital systems do not execute instructions; they are hardwired. C and D: Speed does not define the category; some fixed-function logic outruns general-purpose processors. Common Pitfalls: Equating “digital” with “programmable”; many digital devices are not instruction-driven. Final Answer: The microprocessor follows a programmed sequence of instructions that the designer specified.

Question 4

PAL architecture — path of product terms in combinational mode In a typical programmable array logic (PAL), each gate product term is ORed, and for combinational logic the resulting sum is then:

Accepted Answer

Introduction / Context: PAL devices use a programmable AND array followed by a fixed OR array. Understanding the signal path in combinational mode clarifies how polarity and buffering are handled before a logic signal reaches the output pin. Given Data / Assumptions: PAL: programmable AND array + fixed OR array. Combinational mode (no register stage). Output polarity and buffering are typically provided by an output inverter/buffer. Concept / Approach: Product terms are generated in the AND array. These terms are summed by the OR array to form the desired logic function. In standard PALs, the summed signal passes through an output buffer/inverter whose polarity may be programmable (via a “polarity fuse”). Thus, in combinational mode, the ORed signal does not go raw to the pin; it is routed through an inverter/buffer stage first. Step-by-Step Solution: Generate product terms in the AND plane.Sum selected products in the OR plane.Route sum to the output inverter/buffer for proper polarity and drive.Deliver final signal to the output pin. Verification / Alternative check: Check canonical PAL block diagrams: after the OR array, an inversion/polarity option is shown before the pad. Why Other Options Are Wrong: C: Skips the essential output buffer/inverter stage. D: Signal does not return to the AND plane after ORing. A: “Polarity fuse is restored” is not an operation step; polarity is configured, not dynamically restored. Common Pitfalls: Confusing PAL with PLA or GAL variants; while implementations differ, the output buffer/inverter remains standard in combinational mode. Final Answer: sent to an inverter for output

Question 5

CPLD composition — internal building blocks Within a complex programmable logic device (CPLD), the PAL-like simple PLD structures are organized into units commonly called:

Accepted Answer

Introduction / Context: CPLDs scale up the PAL/SPLD concept by combining multiple logic blocks with extensive interconnect. The terminology for these building blocks is essential when reading datasheets and fitting logic during synthesis. Given Data / Assumptions: CPLD = multiple logic blocks inside a single chip. Each block houses logic resources and registers. Vendors may vary names slightly, but “macrocell” is industry-standard. Concept / Approach: A macrocell typically contains the OR-summed product terms, an optional register (flip-flop), output enable control, and programmable polarity. Many macrocells aggregate into logic array blocks (LABs), which are then interconnected via a programmable routing matrix to form the full CPLD. Step-by-Step Solution: Recognize SPLD-like elements packaged into larger units.Identify industry term: “macrocell.”Recall that groups of macrocells form LABs or function blocks in vendor diagrams.Map to option list: macrocells is the correct designation. Verification / Alternative check: Vendor documentation (e.g., Altera/Intel MAX7000, Xilinx XC9500) consistently uses the term macrocell for the basic logic/register element. Why Other Options Are Wrong: Microcells: not standard nomenclature for CPLDs. AND/OR arrays and fuse-link arrays: these are structural components, not the encapsulated functional unit name. Common Pitfalls: Confusing macrocell vs. LAB naming; macrocells are the per-output logic units, LABs are groups of macrocells. Final Answer: macrocells

Question 6

GAL16V8 device modes — identifying supported operating modes Which of the following are valid operating modes for a GAL16V8 programmable logic device?

Accepted Answer

Introduction / Context: GAL (Generic Array Logic) devices, such as the GAL16V8, are pin-compatible, fuse-map compatible successors to classic PALs with reprogrammability. They offer multiple operating modes to trade off I/O usage, product term resources, and sequential capability. Given Data / Assumptions: GAL16V8 supports multiple personality modes. “Simple,” “Complex,” and “Registered” are common vendor-stated modes. Mode selection is determined by the design and fitter software. Concept / Approach: In Simple mode, outputs behave as straightforward combinational functions with abundant product term sharing. In Complex mode, macrocells offer richer control including output enable and more flexible product-term allocation. Registered mode dedicates macrocells to include flip-flops for synchronous designs, enabling counters and state machines directly in the device. Step-by-Step Solution: List vendor-documented modes: Simple, Complex, Registered.Recognize that each mode corresponds to a pin/function mapping template.Therefore, all listed modes are valid for a GAL16V8.Select “All of the above.” Verification / Alternative check: Reference a GAL16V8 datasheet or fitter options; the three modes appear explicitly. Why Other Options Are Wrong: Each single-mode choice is incomplete; the device supports more than one mode. Common Pitfalls: Assuming PAL-like fixed personalities; GALs add flexibility via reprogrammable logic and multiple modes. Final Answer: All of the above

Question 7

Expanders make it possible to increase the number of terms in a programmable SOP operation.

Accepted Answer

True

Question 8

All inputs to the MAX7000S device and all macrocell outputs feed the PIA.

Accepted Answer

True

Question 9

Using a hardware solution for your digital system design is always faster than a software solution.

Accepted Answer

True

Question 10

Most complex digital designs include a mix of different hardware categories.

Accepted Answer

True

Question 11

With microcomputer/DSP systems, devices can be electronically controlled and data can be manipulated by executing a program of instructions that has been written for the application.

Accepted Answer

True

Question 12

The SRAM technology is volatile.

Accepted Answer

True

Question 13

PLDs cannot meet all the possible requirements of complex digital circuitry.

Accepted Answer

False

Question 14

The GAL chip uses an EEPROM array that is erasable and reprogrammable at least 1000 times.

Accepted Answer

False

Question 15

In a PLD, a blown fuse at an OR gate is a LOW and a blown fuse at an AND gate is a HIGH.

Accepted Answer

True

Question 16

The schematic editor allows you to connect with predefined logic symbols.

Accepted Answer

True

Question 17

Gate arrays are ULSI circuits that offer hundreds of thousands of gates.

Accepted Answer

True

Question 18

The MAX+PLUS II compiler will automatically program a macrocell to borrow up to six product terms from each of three adjacent macrocells in the same LAB.

Accepted Answer

False

Question 19

VHDL code is divided into three sections: library declaration, entity declaration, and architecture body.

Accepted Answer

True

Question 20

The JTAG signals are named TDI, TDO, TMS, and TCK.

Accepted Answer

True

Programmable Logic Device Questions