Jumping back on board the digital train - part III

Apart from an architecture which is attractive to program in, I also have several other demands on the checklist for the digital toys I'm going to pin my colours to. Ease of entry into the game and low cost development tools are a must.

Arduino is a phenomenon I did a little research into. Its become jolly popular over the past six years or so since its inception and I wanted to understand some of the reasons for its acceptance. One of the reasons has to be its open source nature. Another is the well written materials to get you going - they've put quite a lot of thought into the practical issues, even inventing their own vocabulary for elements in the process - 'sketches' springs to mind. If there's a weakness in what they're doing its this - its tied to Atmel as they're the vendors of the chips used. There are no second sources of the parts to my knowledge. This vendor-specific approach doesn't sit at all well with the open-source side - Atmel's architecture is unique to them.

A more recent upstart is XMOS - at first I was really taken with their totally fresh approach to processor design. What appealed at first is the inherent scalability of the multicore architecture and the promise of getting really close to the hardware with their extensions to C (called XC). Over two years ago I bought their evaluation board in a bout of sudden enthusiasm. One year later they released a USB 2.0 high speed audio interface and I felt they were making all the right choices to hook me into their ecosystem. Another tasty morsel was their implementation of an SPDIF receiver entirely in software - well impressive! I bought the USB eval board too, but both have remained on my shelf, unopened. The potential really seems awesome yet something must be missing or I'd have started playing with those two boards by now - I'll talk a little later about my misgivings over XMOS.

Microchip is the 'Intel'-style player to Atmel's 'Motorola' in embedded micros. I've admired Atmel's AVRs from a distance and read articles explaining the architecture. Where Atmel's architectures are clean and elegant, Microchip's are clunky and idiosyncratic. But for my money Microchip (rather like Intel) has the best marketing and manufacturing. Stories abound about not being able to get hold of Atmel parts, but Microchip is solidly reliable. So pick your poison between these two vendors

What I've begun to notice is the way I get swayed in the making of my decisions is by examples - real applications demonstrated. I have a QA550 wav file player - this uses a dsPIC33 processor. I went over to the Microchip website and downloaded the datasheet for the part they use - really hard to get a feel for what its capable of reading that. I also checked out the roadmaps. I did not get the impression that Microchip was really going anywhere with that line of chips - it seems not part of a consistent development path. I'm a bit of a power freak (that's an aspect of what drew me to XMOS, that's a 400MHz device) and they topped out at 40MHz. Seems like rather a dead-end and its only 16bits to boot.

Another interesting example is an MP4 player I bought several years ago. Its an ADI Blackfin based device. Very impressive on paper and there's plenty of activity on their roadmap. But being ADI they're targeting industrial users so there's a complete zilch on available and affordable development kits. I have one myself, from attending an ADI seminar years ago, but its never been powered up. Its also only 16bits and targeted more at video than audio it seems.

OK, enough of all the 'also rans' - in the next part I'll start talking about the chips that have impressed me...