8-bit PICs for safety critical systems

DSP, Micros & Memory

4 June 2014 DSP, Micros & Memory

Microchip announced an expansion of its 8-bit PIC microcontroller (MCU) portfolio, with the peripheral-rich, low pin-count PIC16(L)F161X family.

These new MCUs expand the offering of Microchip’s Core Independent Peripherals (CIP), which off-load timing-critical and core-intensive tasks from the CPU, allowing it to focus on other application tasks. In addition, this family integrates fault detecting hardware features to assist engineers in developing safety critical applications.

The PIC16(L)F161X family offers a variety of key features, including the windowed watchdog timer (WWDT), which monitors proper software operation within predefined limits to improve reliability. The cyclic redundancy check with memory scan (CRC/SCAN) detects and scans memory for corrupted data.

This range also includes a hardware limit timer (HLT), which detects hardware fault conditions, including stall and stop, to simplify closed-loop control applications. These peripherals make it easier for designers to implement safety standards such as UL and class B, or fail-safe operation.

In addition to the HLT, the PIC16(L)F161X features the unique, 24-bit signal measurement timer (SMT), which performs high-resolution measurements of any digital signal, in hardware, resulting in more precise and accurate measurements. This is ideal for speed control, range finding and RPM indicators. Both timers are designed to reduce design complexity by eliminating the need for additional code and external components.

This high level of integration makes these MCUs appealing to a broad range of applications, such as monitoring and fail-safe systems including industrial machinery and power supplies, as well as products with variable-speed motor control such as fans and home appliances.

These are also the first PIC MCUs to offer hardware zero cross detect (ZCD), which is essential for designers looking to simplify TRIAC control and increase system robustness by minimising the EMI caused by switching transients.

A complementary waveform generator (CWG), comparators, 10-bit ADC, 8-bit DAC and capture/compare PWM are also integrated. The CWG can generate complementary waveforms with fine control of key parameters, such as polarity, deadband and emergency shutdown states. It provides a cost-effective solution for half-bridge and full-bridge drive control.

All of these features are provided in small-form-factor packages, ranging from 8 to 14 pins.

For more information contact Shane Padayachee, Avnet Kopp, +27 (0)11 319 8600, shane.padayachee@avnet.eu, www.avnet.co.za

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8-bit PICs for safety critical systems

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