Add safety-critical features to control applications with 8-bit PICs
Low pin-count PIC16(L)F161X devices add to Microchip’s Core Independent Peripherals (CIP), which off-load timing-critical and core-intensive tasks from the CPU. These devices integrate fault-detecting hardware features for safety-critical applications. The Windowed Watchdog Timer (WWDT) monitors proper software operation within predefined limits. The Cyclic Redundancy Check with Memory Scan (CRC/SCAN) detects and scans memory for corrupted data. This family 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 & class B, or fail-safe operation.
In addition to the HLT, the PIC16(L)F161X features the 24-bit Signal Measurement Timer (SMT). The SMT performs high-resolution measurements of any digital signal, in hardware, resulting in more precise and accurate measurements. This is suited to 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. These are also the first PIC MCUs to offer hardware Zero Cross Detect (ZCD), 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, to enable design flexibility and overall cost reduction. The CWG can generate complementary waveforms with fine control of key parameters, such as polarity, dead-band and emergency-shutdown states. It provides a cost-effective solution for half-bridge and full-bridge drive control, which saves both board space and component cost when driving FETs in motor-control and power-conversion applications. All of these features are provided in small-form-factor packages, ranging from 8 to 14 pins.
Microchip asserts that coding and additional hardware associated with implementing safety and control in an embedded system can be reduced by exploiting these integrated hardware features. PIC12(L)F1612 MCUs come in 8-pin PDIP, SOIC, and 3 x 3 mm DFN and UDFN packages. The PIC16(L)F1613 MCUscome in 14-pin PDIP, SOIC, TSSOP, and 4 x 4 mm UQFN and QFN packages. More at; www.microchip.com/get/VDLM
next; 8bits with hi-res PWM
Also added by Microchip, and relevant to control and automation designs, are 8-bit PICs with three high-resolution 16-bit PWMs, in 8-pin packages. PIC12(L)F157X family chips have multiple 16-bit PWMs with an assortment of analogue peripherals and serial communications in an 8-pin package. These MCUs deliver three full-featured 16-bit PWMs with independent timers, for applications where high resolution is needed, such as LED lighting, stepper motors, battery charging and other general-purpose applications. In addition to standard and centre-aligned PWM output modes, the peripheral also has four compare modes and can serve as an additional 16-bit timer. A Complementary Waveform Generator (CWG), in combination with the 16-bit PWMs, can be used to create half-bridge and full-bridge drive control. The CWG and 16-bit PWMs are Core Independent Peripherals (CIP) which are coupled with the 10-bit ADCs, comparator and 5-bit DAC Analogue Peripherals to enable closed-loop feedback and control. The PIC12F157X MCUs are suited for a wide range of applications, such as indoor/outdoor LED lighting, and RGB LED colour mixing; consumer applications such as electric razors and radio-control toys; and automotive interior LED lighting.
The PIC12F1572 enables communication with an EUSART, enabling general-purpose serial communication and LIN for automotive and industrial control. The integrated 10-bit ADCs enable human-interface/touch applications using Microchip’s capacitive mTouch sensing solution. Additionally, the chips offers non-volatile data storage via High Endurance Flash (HEF) memory. The “LF” versions feature low-power technology, for active currents of less than 35 µA/MHz and sleep currents down to 20 nA, which is ideal for battery-powered applications.
Microchip; www.microchip.com/get/G6RB
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