The folks from Microchip have just announced a new suite of MCUs -- the PIC24F "GC" family -- which offers the highest analog integration of any PIC MCU thus far.
Featuring Microchip's eXtreme Low Power (XLP) technology, PIC24F GC devices consume only 18 nA in Sleep mode and 180 µA/MHz when running. These devices also boast integrated USB, LCD driving, and touch sensing capabilities. All of these attributes mean that PIC24F GC devices are ideal for portable medical and industrial applications.
Key analog features of the PIC24F GC family are a 16-bit sigma-delta analog-to-digital converter (ADC), a 12-bit 10 Msps pipeline ADC, a 10-bit 1 Msps digital-to-analog converter (DAC), dual op-amps, comparators, voltage references, and an analog interconnect switch.
Consider a blood meter application for example. Some designers may prefer to use the 16-bit ADC for high accuracy with reduced throughput, while others may choose to use the 12-bit ADC for higher throughput at a lower resolution. Much of this depends on the chemistries being measured. In some cases designers may use both ADCs, sampling quickly at a lower resolution until the area of interest is reached, and then swapping to a lower sample rate at a higher resolution.
The reason the folks at Microchip refer to all of this as "intelligent analog" is that all of the analog design was performed by Microchip -- they debugged the noise and communication so that designers obtain consistent analog performance across applications.
The benefits of integrating the analog on the MCU include faster data paths, reduced noise, and the ability to change the analog parameters in software, all of which help to simplify board designs and reduce cost and board space. For example, consider the following board design without and with PIC24 GC intelligent analog:
Without Microchip PIC24 GC intelligent analog.
With Microchip PIC24 GC intelligent analog.
PIC24F GC MCUs boast a wide variety of flexible user interface peripherals, including a segmented LCD driver capable of handling 472 segments offering scrolling character displays and highly descriptive icons. As an example application, consider a glucose meter as illustrated below:
The integrated analog -- fast 12-bit ADC and high-resolution 16-bit ADC coupled with a complete signal chain comprising op-amps and the 10-bit DAC -- reduces costs and simplifies the design. The rich information display (which offers both Western and Asian characters) can be used to provide textual and graphical guidance to the user, including adjustable text size for seniors. The USB interface can be used to send data to a physician or upload it to the Internet. And the use of eXtreme Low Power technology means the device can run for as long as 10 years on a coin cell (longer with an AAA lithium battery).
In order to get designers "up and running," Microchip also offers a PIC24F Starter Kit for Intelligent Analog (cost = $89.99; part number = DM240015; availability = now) as illustrated below:
This little rascal offers an analog header, with "clean" analog signals, that plugs into breadboards. It boasts on-board sensors and a built-in programmer/debugger. And it comes equipped with pre-loaded software for scrolling text, touch sensing, level indicators, menuing, ADC measurement, and USB data streaming.
Click here for more information on the PIC24F GC MCU family; and click here to see a video.