Building Block Solution for Embedded System FAQs

The BB91A32A Building Block Solutions (BBS) – Embedded Systems Kit is a modular demonstration platform containing several analog, mixed-signal and microcontroller devices configured in separate BBS boards. It is designed for easy evaluation and implementation in system-level applications. The modular format allows users to seamlessly integrate individual boards into existing systems or configure multiple boards together for diverse application requirements, which enables rapid prototyping, system expansion and customized solutions.

The kit includes the following 10 BBS boards:

• PIC16F17576 BBS: Features the PIC16F17576 microcontroller, which excels in low-power and robust analog applications, and it includes a new low-power voltage reference (V_REF) and comparator capable of analog thresholding at under 3 µA, plus four op amps, two 8-bit Digital-to-Analog Converters (DACs), a 12-bit differential Analog-to-Digital Converter (ADC), and an Analog Peripheral Manager—a highly integrated and power-sensitive PIC16 analog portfolio
• MCP3564R BBS (BB88G26A): Features the MCP3564R 8-channel, 24-bit, 153.6 ksps Delta-Sigma ADC with internal voltage reference, oscillator, temperature sensor and burnout sensor detection; extensive software, firmware examples, Application Programming Interfaces (APIs) and an evaluation board are available
• MCP42U83 BBS: Features the MCP42U83 10-bit dual-channel digital potentiometer; can operate with single-ended or dual power supply with no initial configuration needed; configurable as a potentiometer or rheostat, the internal resistor ladder has 1,023 resistors with 1,024 wiper connection points
• Non-Inverting Amplifier BBS: Features a SOT23-5 op-amp footprint (populated with MCP6V11) configurable by the user as a non-inverting amplifier, voltage follower, Sallen-Key filter or difference amplifier; all resistor/capacitor positions are unpopulated for user configuration
• Inverting Amplifier BBS: Features a SOT23-5 op-amp footprint (populated with MCP6V11) configurable by the user as an inverting amplifier, multiple feedback low-pass filter, or multiple feedback band-pass filter. All resistor and capacitor positions are unpopulated for user configuration.
• Potentiostat Circuit BBS: Features a potentiostat circuit design with an unpopulated footprint for the user to add an electrochemical gas sensor of their choice
• MCP9700B BBS (BB93Z17A): Features the MCP9700B analog output temperature sensor, which converts temperature to an analog voltage between 0V and V_DD; with a 12-bit ADC and 4.096V reference, it outputs 0.1°C per bit resolution
• MCP1501-18 BBS (BB17J62A): Features the MCP1501-18 high-precision 1.8V buffered voltage reference capable of sinking and sourcing 20 mA of current
• MCP16251-33 BBS: Features the MCP16251/2 compact, high-efficiency, fixed-frequency synchronous boost DC-DC converter. Suitable for applications powered by one-cell, two-cell or three-cell alkaline, NiCd, NiMH, or one-cell Li-Ion/Li-Polymer batteries
• MIC5317 BBS: Features the MIC5317 high-performance 150 mA Low-Dropout (LDO) regulator with high power supply rejection; operates from 2.5V to 6.0V input and provides output voltages from 1.0V to 3.6V for USB-port or 6V AC adaptor applications

The boards come fully populated with their key Surface-Mount Device (SMD) components. For evaluation, you will need:

• Header pins (not included) for connectivity between boards and external equipment
• An external laboratory power supply
• An oscilloscope for signal monitoring and data acquisition
• A function generator for signal generation where required

Depending on the specific application, some or all of these components may be required in combination.

The BB91A23A kit is designed for rapid prototyping of embedded system applications. Two example configurations described in the user guide are:

• Electrochemical Gas Sensing: Uses the Potentiostat Circuit BBS, MCP3564R BBS, MCP42U83 BBS, MIC5317 BBS, and MCP9700B BBS to build a complete gas-sensing front-end
• Water Flow Meter: Uses the PIC16F17576 BBS, MCP3564R BBS, non-inverting amplifier BBS, inverting Amplifier BBS, MCP1501 BBS, MIC5317 BBS and MCP9700B BBS to build a precision flow measurement system

The modular design means the boards can also be combined in many other ways to suit custom embedded system development needs.

The BB91A32A kit speeds up prototyping because it provides a pre-configured set of highly diverse building blocks—a microcontroller, precision ADC, digital potentiometer, configurable op-amp stages, power management, voltage reference and temperature sensing—that can be tested, combined and integrated immediately without requiring custom Printed Circuit Board (PCB) design or component assembly.

Select boards based on the signal chain and power requirements of your target application:

• For microcontroller processing and low-power analog control, use the PIC16F17576 BBS
• For high-resolution (24-bit) data acquisition from sensors, use the MCP3564R BBS
• For programmable resistance or variable gain control,  use the MCP42U83 digital potentiometer BBS
• For signal conditioning with fixed gain, use the non-inverting or inverting amplifier BBS
• For electrochemical sensor interfacing, use the potentiostat circuit BBS
• For ambient temperature measurement, use the MCP9700B BBS
• For a stable 1.8V precision reference (e.g. ADC AVDD supply), use the MCP1501-18 BBS
• For boosting a low battery voltage to a regulated supply rail, use the MCP16251-33 BBS
• For a clean regulated LDO supply from USB or adaptor, use the MIC5317 BBS

The power-up procedure for the BB91A32A Building Block Solutions – Embedded Systems kit is:

• Install header pins (not included) into the 4-pin connectors on each BBS board you plan to use
• Connect the power supply to the VDD and GND pins of the boards you are using—supply voltage requirements depend on the specific sub-modules selected (for example, MCP16251 boost accepts 0.35V–1.65V input; MIC5317 LDO accepts 2.5V–6.0V input)
• Connect signal sources, loads or inter-board connections as required by your configuration
• Turn on the supply and monitor outputs with a voltmeter or oscilloscope

Refer to the individual product data sheets for the correct supply voltage range and startup sequencing requirements for each sub-module.

The Non-Inverting Amplifier BBS board ships with an MCP6V11 op amp and a bypass capacitor populated. All resistor and capacitor positions are left unpopulated for the user to configure. By adding the appropriate external components, the board can be set up as:

• A non-inverting amplifier (gain set by two resistors)
• A voltage follower/unity gain buffer (no gain resistors needed)
• A Sallen-Key low-pass or high-pass filter (two resistors and two capacitors)
• A difference amplifier (four resistors)

Refer to the MCP6V11 data sheet and standard op amp application circuit references for component value selection.

The Inverting Amplifier BBS board ships with an MCP6V11 op-amp and a bypass capacitor populated. All other component positions are left unpopulated for the user to configure. By adding external components, the board can be set up as:

• An inverting amplifier (gain set by two resistors)
• A Multiple Feedback (MFB) low-pass filter (two resistors and two capacitors)
• A Multiple Feedback (MFB) band-pass filter (three resistors and two capacitors)

Refer to the MCP6V11 datasheet and standard active filter design references for component value selection.

The MCP9700B is an analog output temperature sensor that converts temperature to a proportional analog voltage between 0V and VDD. The output voltage relationship is:

• Temperature (°C) = (VOUT – 500 mV) / 10 mV/°C

When paired with a 12-bit ADC and a 4.096V reference (such as the MCP1501-40 or the MCP3564R's internal reference), the sensor delivers 0.1°C per bit of resolution. The operating temperature range of the MCP9700B is –40°C to +150°C.

The MCP3564R is an 8-channel, 24-bit, 153.6 ksps Delta-Sigma ADC with an internal voltage reference, oscillator, temperature sensor and burnout sensor detection. Key features that make it suitable for precision embedded measurement include:

• 24-bit resolution for high-accuracy measurement of small signals
• 8 differential or single-ended input channels
• Internal voltage reference, oscillator and temperature sensor, reducing the need for external components
• Burnout sensor detection for open-circuit fault detection on sensor inputs
• Extensive software and firmware examples, APIs, evaluation board support and a weight-scale reference design available on the product page

The MCP42U83 is a 10-bit dual-channel digital potentiometer that can operate with either a single-ended or dual power supply without requiring initial configuration. It is used in this kit to provide programmable resistance values in analog signal chains. Key characteristics include:

• 1,023 resistors with 1,024 wiper positions from zero to full scale
• Configurable as a potentiometer (voltage divider) or as a rheostat (variable resistor) via a dedicated register
• No initial configuration required for power supply selection

In the Electrochemical Gas Sensing application example, the MCP42U83 is used to set bias and gain conditions in the signal conditioning chain.

The Potentiostat Circuit BBS board is designed for electrochemical sensor interfacing. A potentiostat is a control circuit used to maintain a fixed potential difference between a working electrode and a reference electrode in an electrochemical cell, which is the standard way to drive and measure electrochemical gas sensors. The board ships with an unpopulated footprint so the user can solder on an electrochemical gas sensor of their own choice. It is a key component of the Electrochemical Gas Sensing application example in the user guide.

The MCP16251-33 BBS board features the MCP16251/2, a compact, high-efficiency, fixed-frequency synchronous step-up (boost) DC-DC converter. It steps up a low input voltage — from a battery, for example — to a higher regulated output. The MCP16251 is designed for applications powered by:

• One-cell, two-cell or three-cell alkaline batteries
• NiCd or NiMH battery packs
• One-cell Li-Ion or Li-Polymer batteries

The board in this kit is configured for a 3.3V output (-33 suffix). This makes it useful for powering 3.3V digital logic or sensors from a low-voltage battery source.

These two boards serve complementary power management roles:

• MCP16251-33 (Boost Regulator): Steps a low input voltage UP to a higher output voltage; used when the supply (for example, a single-cell battery) is below the required system rail voltage; input voltage range is typically 0.35V–1.65V for single-cell operation
• MIC5317 (LDO Regulator): Steps a higher input voltage down to a lower, cleaner regulated output; input voltage is 2.5V–6.0V; output voltage is 1.0V–3.6V; provides high power supply rejection, making it well suited for noise-sensitive analog circuits

In a typical system, the boost regulator might generate the main supply rail from a battery, while the LDO provides a clean, low-noise regulated supply to sensitive analog components downstream.

Appendix A of the user guide contains the full board schematics and PCB layer views for the BB91A23A kit, including individual schematics for all 10 sub-module boards:

• PIC16F17576
• MCP3564R
• MCP42U83
• Non-Inverting Amplifier
• Inverting Amplifier
• Potentiostat
• MCP9700B
• MCP1501-18
• MCP16251-3.3
• MIC5317

PCB layer views include: Top Silk, Top Copper and Silk, Top Copper, Bottom Copper, Bottom Copper and Silk, and Bottom Silk.

Appendix B of the user guide contains the complete Bill of Materials (BoM) (Table B-1). Key Microchip ICs populated across the kit include:

• MCP42U83T-104E/ST: 10-bit dual digital potentiometer, TSSOP-14
• MCP6V11T-E/OT: Single-channel 80 kHz op amp, SOT-23-5 (used in amplifier BBS boards)
• MCP6V14-E/ST: Quad-channel 80 kHz op amp, TSSOP-14
• MCP9700BT-H/TT: Analog temperature sensor, –40°C to +150°C, SOT-23-3
• MCP1501T-18E/CHY: 1.8V precision voltage reference, SOT-23-6
• MCP16251: Synchronous boost regulator, SOT-23-6
• MIC5317-3.3YD5: 150 mA LDO regulator 3.3V, TSOT23-5
• PIC16F17576-I/MP: 8-bit MCU, 32 MHz, 28 KB Flash, 2 KB RAM, QFN-40
• MCP3564RT-E/NC: 24-bit Delta-Sigma ADC, UQFN-20

Each sub-module has its own product page on the Microchip website with data sheets, application notes, software and collateral:

• PIC16F17576
• MCP3564R
• MCP42U83
• MCP9700B
• MCP1501
• MCP16251
• MIC5317