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Learn how to get more signal chain from the MCU in factory automation applications

As factories become increasingly smarter, so does we have useful to produce the sensors, automation and equipment that controls and monitors these installations. Microcontrollers (MCUs) will need to efficiently accommodate various kinds of sensing and measurement applications, in particular those between sensing of, humidity, temperature, power current, lethal, many other conditions or parameters. One fashion to address the demand for adaptability is by integrated flexible analog signal-chain configurations throughout the MCU that may be adjusted to meet specific application needs.

This integrated signal-chain approach can be a key element in the new MSP430FR23xx MCU family, with multiple configurable smart analog combo peripherals. The smart analog combo comprises several analog signal-chain elements including an operational amplifier (op amp) with programmable gain amplifier (PGA) capability plus a 12-bit digital-to-analog converter (DAC). These peripherals offer many configuration options, making it possible to configure the inner signal path depending on the job. Figure 1 is actually a high-level block diagram of a smart analog combo module.

Figure 1: Smart analog combo module in the MSP430FR2355 MCU

The MSP430FR2355 device includes four smart analog combo modules, where you can configure each independently through the next decide on combinations of DACs, PGAs and op amps as required for the application. There’s also some options allowing the interior routing of a smart analog combo towards a paired module, which minimizes the need for external signal-chain connections. The MCU includes a 200KSPS 12-bit successive approximation (SAR) analog-to-digital converter (ADC) and 2 enhanced comparators to present more signal chain elements inside MCU.

One application to your smart analog combo additionally, the MSP430FR2355 MCU’s -40 to 105C operating climate is a temperature transmitter present in sensing applications in factories. The 4mA to 20mA loop-powered resistance temperature detector (RTD) temperature transmitter reference design featuring the MSP430FR2355 MCU offers a low-component count, low-cost solution. The reference design uses the on-chip smart analog combo modules from the MSP430FR2355 MCU to manage the loop current so a stand-alone DAC is no longer required, as shown in Figure 2.

Figure 2: 4mA to 20mA current-loop temperature transmitter reference design block diagram

This design achieves a 12-bit output resolution along with an output current resolution of 6A. The form also incorporates reverse-polarity protection, as well as International Electrotechnical Commission (IEC) 61000-4-2 and IEC61000-4-4 protection about the loop-power input. Figure 3 shows a hardware useful for testing this design.

Figure 3: Temperature transmitter reference design while using the MSP430FR2355 MCU

The increase of sensing applications within factory automation is driving the need for more analog and peripheral integration within MCUs. Adding configuration to integrated analog elements provides flexibility to developers to deal with the varying needs of factory automation systems.