I'd like to buy a µ

The net number of microprocessor offerings available to embedded developers continues to grow every year. Each update of the microprocessor directory is our attempt to help you improve your chances of being aware of and considering the best processor options for your design in this constantly changing landscape. Consider the sheer size of this year’s microprocessor directory. The device table alone is 172 pages – in a 6 point font – and the table mostly lists product families under a single entry rather than every possible device available as a separate entry. The company overview and product family detail pages approach 100,000 words in content.

One thing to note is that the number of ISAs (instruction set architectures) has not been consolidating. However, this does not seem to be a problem – I think in part because contemporary processors have good enough compilation support that effectively abstract the underlying architecture. As a test to see if ISAs were no longer a primary search criteria, we decided to quietly omit the device table listings that sorted the devices by instruction set architecture. The information is still in the tables, there just has not been a specially sorted listing that focused on common ISA. I was a little nervous about removing the listed tables because even as recent as a few years ago, I received emails from people commenting on the ISA-sorted listing – especially with regards to the 8051 offerings. I’m relieved to report that I am unaware of any comments or inquiries about the missing listings since last year. I’m explicitly identifying the omitted ISA-sorted listing now to provide an explicit feedback path in case I misinterpreted the current trend that suggests ISAs are not a primary differentiator for processor choices anymore.

I took this thesis a step further and structured a hands-on project around it. In the project, I worked with four different application engineers to port an open source audio codec to four different processors. As expected, the compilers and development tools were up to the task in each case. The majority of the porting effort was in working with the differentiation in peripheral, memory, and bus architectures in each device – resources that are adequately captured in standard C code for the compiler to compensate for. On the other hand, none of these ports targeted an RTOS; if they did, there might have been less effort necessary for each port as the device drivers are abstracted by the operating system calls.

I’d like to remind you that the continually growing size of the directory has been a major concern of mine for years. A more complete collection of information is good, but it loses value if you cannot find what you are looking for. That is why, over the years, we have experimented with how to organize the data and make it easier for you to find the information most important to you without having to wade through all of the material. Unfortunately, building the directory is a manual effort. The data is collected, edited and marketing material purged, organized, and ultimately loaded into the web database you see by hand.

It has been my goal for years to support dynamic search and filtering capabilities, but business constraints have prevented that. I receive emails every year asking for a sortable version of the device table. Unfortunately, I cannot make that type of file directly available for download. We experimented with an online sorting capability a few years ago, but it did not work as well as it needed, so we discontinued using that technology. We are currently exploring how to add cross-linking between devices in the product detail pages so that when you find one device that approaches what you are looking for, you can more easily find similar devices that compete with or complement it.

I would like to encourage you to post here what one or two capabilities or changes would best improve the utility of the directory for you. I hope to be able to use your responses to build a business case. The directory is a living project; please help to make it better with each iteration.

You can always reach the most current directory by visiting www.edn.com/microdirectory, but that link also has a listing to previous editions of the directory. Each year we receive several requests for past information. Also, the archives make it possible for you to find information on older architectures that are no longer available or help you track down where those architectures may have transferred to.