Low-cost 8-bit PICs gain analogue blocks for capacitive touch

September 23, 2014 // By Graham Prophet
The PIC16LF1554/9 combines low power and dual ADCs with a hardware capacitive voltage divider (CVD) for capacitive-touch sensing, to reduce software overhead for advanced touch-sensing and general-purpose sensor applications.

Microchip's 8-bit microcontroller (MCU) family has been augmented with with the PIC16LF1554 and PIC16LF1559 (PIC16LF1554/9) devices. The PIC16LF1554/9 includes two independent 10-bit 100 ksamples per second ADCs with hardware capacitive voltage divider (CVD) support for capacitive-touch sensing. This ADC configuration enables more efficient sensor acquisition and assists with advanced touch-sensing techniques for extremely noisy environments, low-power applications, matrix keypads and water-resistant designs.

The 14- and 20-pin PIC16LF1554/9 MCUs combine up to 17 ADC channels with automated hardware CVD modules to implement capacitive sensing and other front-end sampling applications with minimal software overhead. In particular, the hardware CVD reduces the code for implementing capacitive touch-sensing by more than 40%. The devices also include up to 14 kB Flash/512 Bytes RAM, a 32 MHz internal oscillator and two PWM modules, as well as I²C, SPI and EUSART for communications. Additionally, they are eXtreme Low Power (XLP) compliant with active and sleep currents of 35 µA/MHz and 30 nA, respectively. These features, combined with the low cost and small footprint of the PIC16LF1554/9, make them suitable for a wide range of applications in consumer electronics, such as remote controls, audio players, cell phone accessories, small appliances, wearable devices including headphones, watches and fitness wristbands; in medical applications such as blood-pressure monitors and wearable heart-rate monitors; in the automotive market for automotive interior controls and control panels; and in industrial markets such as RFID and sensors.

Support for the PIC16LF1554/9 MCUs comes in the MPLAB X Integrated Development Environment (IDE); PICkit 3 (PG164130) priced at $44.95; MPLAB XC8 Compiler for 8-bit PIC MCUs and MPLAB Code Configurator. The devices come in 14-pin PDIP, TSSOP, SOIC and 16-pin QFN (4 x 4 x .9 mm) packages (PIC16LF1554) and 20-pin PDIP, SSOP and QFN (4 x 4 x .9 mm) for the PIC16LF1559.

Microchip; www.microchip.com/get/08KC