Motor-control functions shape 8-bit microcontroller feature set

August 02, 2013 // By Graham Prophet
F85x/6x MCUs from Silicon Labs offer analogue integration in small packages, supported by a new free-of-charge suite of Keil tools for 8-bit design

These highly integrated, 8-bit microcontrollers (MCUs) are optimised for cost-sensitive motor control applications. The new C8051F85x/6x MCUs combine analogue and communications peripherals, flash sizes ranging from 2 kB to 8 kB, high performance, small-footprint packaging and cost-effective pricing, making them suitable for brushless dc motor control applications used in toys, PC and electric fans, electric tools and small appliances. The F85/6x MCUs are a good fit for other consumer and industrial applications such as power supplies, battery chargers, set-top boxes, projectors, lighting equipment and optical transceiver modules. These AEC-Q100-qualified MCUs can also be used in automotive body electronics applications such as window lifts and power seats.

For developers seeking economical mixed-signal MCU solutions that provide high levels of integration and processing performance for analogue-intensive and computationally demanding applications such as motor control. The F85x/6x MCUs feature a high-speed 8051 core that is 50% faster than the closest competitors. This performance enables finer pulse-width modulation (PWM), enhanced motor control efficiency and the ability to execute more complex algorithms for a broad range of motor speeds. The F85x/6x MCUs also support three independent high-resolution PWM channels with a built-in overcurrent protection/fault detection capability specifically targeting motor control and power supply applications.

The F85x/6x MCUs integrate advanced analogue and digital peripherals into a small package. The MCUs include a 12-bit multi-channel analogue-to-digital converter (ADC), two analogue comparators with programmable hysteresis and response time, and a precise internal voltage reference. The MCUs also feature an integrated precision 24.5 MHz low-power oscillator and a low-frequency 80 kHz oscillator, eliminating the need for an external clock or crystal. An on-chip temperature sensor simplifies system calibration without having to add a discrete sensor. Multiple communications peripherals (I2C, SPI and UART) also give developers the flexibility to choose their peripherals based on application requirements. The combination of all these on-chip features enables developers to minimise external components, resulting in lower system cost compared to competing MCUs.

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