Built-in self-test (BIST) has been applied to test an analog to digital converter (ADC) and a digital to analog converter (DAC) embedded in a DSP-core ASIC. The performance characteristics of the ADC and the DAC designed in according with the CCITT recommendations are measured using BIST. Three characteristics have been evaluated and the measured results have shown good agreement with measured results by conventional tests. In the BIST operation, the DSP-core generates input stimulus and analyzes output response. Therefore, test-time is reduced, analog or mixed-signal test equipment is not needed, and finally, test-cost is reduced compared with conventional test methods. This paper describes the BIST design and evaluational results.>

A single-chip data-driven microprocessor with special functions for distributed parallel processing is described. The implemented functions necessary for parallel processing are: relative addressing mode for program memory; efficient test and set operation of arbitrary data in data memory; transparent access of distributed shared memory; and dynamic load distribution among multiprocessors. With this microprocessor, practical parallel processing systems which exploit a wide area of scientific applications can be constructed.>

The authors describe a built-in self-test (BIST) method implemented in a 24-b floating-point digital signal processor (DSP) using pseudorandom patterns. By use of only one pair- of LFSRs (linear feedback shift registers) and 253 words of normal instruction, 95% of the functional blocks are self-tested. The number of the test vectors is 35 million. However, the entire BIST takes only 2.6 s for the test, owing to the fast machine cycle time of 75 ns. The overhead of the test hardware is only 2.0% of the die size. The evaluation results show that a BIST is very useful for computationally intensive VLSI processors, such as a DSP.>

An effective layout design method for VLSI processors, called the 'macrocell approach' is presented. The approach bridges the gap between full manual layout and polycell/standard cell layout with respect to the design productivity and the performance. After precise floorplanning, functional blocks are designed into macrocells using a flexible symbolic layout method, and a VLSI chip is laid out by an automatic layout program. A 16-bit digital signal processor (DSP) was designed using 2- mu m CMOS technology. Both high packing density of 1150 transistors/mm/sup 2/ and high productivity of 6.5 transistors/day for symbolic layout were attained in the design. After fabrication, the chip operated with the first silicon, realizing high-speed operation in an application program for a 32-kb/s ADPCM CODEC (adaptive differential pulse-code modulated coder-decoder).>

A custom VLSI design technique, using an integrated CAD system is described. The design system features on the hierarchical design process and layout design capability by system designers (customers). As for application, high-performance LSI's for 16-bit CPU were developed. The LSI design was accomplished in a short period (three months with three designers) due to the hierarchical standard cell approach. The LSI chip contains about 20 K transistors in an 8.84 mm X 8.88 mm die area. High-speed operation (machine cycle = 200 ns) and a high density of 291 transistors/mm2 were obtained with low power consumption (1.2 W) owing to the mixed-MOS type standard cell library and this approach.

The propagation delay time of the ED MOS logic gate is precisely analyzed considering input waveform and loading conditions. According to theoretical consideration and circuit analysis, the rise mode delay time tpLH is approximated as a function of the output capacitance of only the gate concerned. The fall mode delay time t.pHL is determined by the input capacitance and output capacitance of the gate concerned. These results allow the easy implementation of the delay model into a logic simulator. A precise delay simulation is attained by considering the delay components, corresponding to each input node, at the output side of the logic element. The propagation delay times of the transmission gate are precisely analyzed. The operations of the transmission gate are divided into two modes; synchronous mode and asynchronous mode. Corresponding to each mode, the transmission gate, the preceding gate, and the succeeding gate have two kinds of delay times. To simulate delay times of each gate precisely, models which treat these three logic elements as one primitive element in a logic simulator have been proposed. The new timing verification method using the delay model is evaluated with respect to delay-time accuracy and execusion time in a logic LSI. Through this method, circuit simulator accuracy is obtained in the short computer run time of a logic simulator.