**8. Built-In-Self-Test**

The Built-In-Self-Test (BIST) can interface with the sensors and other circuits under consideration. It can be built upon modifications of circuits and ideas available in the literature, such as the use of oscillations for mixed signal testing including the production line technique of using standard ring oscillator properties. The BIST is needed due to the fact that there are many interacting subsystems, and an error in one can perhaps drastically affect the operation of others.

BIST circuitry consists of a controller, a pattern generator and a multiple input signature analyzer. The Built-in Self-Test method allows core testing to be realized by commanding the core BIST controller to initiate self test and by knowing what the correct result should be. On-chip testing of embedded memories can be realized by either multiplexing their address and data lines to external SOC I/O pads or by using the core processor to apply enough read/write patterns of various types to ensure the integrity of the memory. This technique

An array of FPPD is made of many individual FPPD that have different cavity thickness and therefore different range of pass band frequencies. The thickness of these oxide cavities is changed gradually in order to cover some desired range of the light spectrum. The array of FPPD can be formed in one or several columns, all entirely under the microchannel. Any light source that is transmitted through the micro channels will eventually reach these FPPD array under the channel. Each individual FPPD will react only to a small spectrum band of the light that is passed through its Fabry-Perot. Each individual FPPD is connected to the electronic circuit on the chip that will perform the signal conditioning and final post data

A block diagram of this circuitry is depicted in Fig. 7. All photodetector p-n diodes in the array of FPPD under the channel produce a current whose magnitude contains information related to light intensity. Furthermore this light intensity, which is absorbed by the photodiodes, depends on the content of the chemicals present in the micro-channel fluid. The main purpose of this electronic circuitry is to collect, condition, and interface these current signals to the post processing circuit. Since the information signals are in the form of

Interface

Micro Processor

Circuitry

diode currents, it is preferred to work with current mode (CM) electronic circuits.

Fig. 7. Companion Electronic circuit connects array of FPPD to the microprocessor

The Built-In-Self-Test (BIST) can interface with the sensors and other circuits under consideration. It can be built upon modifications of circuits and ideas available in the literature, such as the use of oscillations for mixed signal testing including the production line technique of using standard ring oscillator properties. The BIST is needed due to the fact that there are many interacting subsystems, and an error in one can perhaps drastically

BIST circuitry consists of a controller, a pattern generator and a multiple input signature analyzer. The Built-in Self-Test method allows core testing to be realized by commanding the core BIST controller to initiate self test and by knowing what the correct result should be. On-chip testing of embedded memories can be realized by either multiplexing their address and data lines to external SOC I/O pads or by using the core processor to apply enough read/write patterns of various types to ensure the integrity of the memory. This technique

Sensors,

Amplifiers,

And

ADC

processing.

**7. Companion electronic circuitry** 

Array of FPPD

**8. Built-In-Self-Test** 

affect the operation of others.

works best for small embedded memories. Some recommend providing embedded memories with their own BIST circuitry.

For BIST to be effective, there must be a means for on-chip test response measurement, onchip test control for digital and analog test, and I/O isolation. There are three categories of measurements that can be distinguished: DC static measurements, AC dynamic measurements, and time domain measurements. The first of these, DC static measurements, includes the determination of the DC operating points, bias and DC offset voltages and DC gain. DC faults can be detected by a single set of steady state inputs. AC dynamic measurements measure the frequency response of the system under test. The input stimulus is usually a sine-wave form with variable frequency. Digital signal processing (DSP) techniques can be employed to perform harmonic spectral analysis. Time domain measurements derive slew rate, rise and delay times using pulse signals, ramps or triangular waveforms as the input stimuli of the circuit.
