The Coming Crisis in Board Bring-Up

I was reflecting on how much processor speeds, memory, and data transmission rates have increased over the last few decades. And yet the same old tools and techniques are often used to bring up new designs. When do you think we fall off the cliff?

In the early 1980s, I bought my first home computer, an Apple II, and shortly thereafter equipped it with a Hayes 300 baud modem. I was in “geek-heaven” with the computing power that I had at my disposal; after all, who else had a system with a Motorola 6502 processor running at 1MHz, 48kB of RAM, and a whopping 140kB of floppy disk space? But, compare that with what’s common on a desktop today:

 

1981

2011

Gain

Processor

1MHz

3GHz

3,000 X

Memory (RAM)

48kB

6GB

125,000 X

Data bandwidth

300bps

15Mbps

50,000 X

Memory (non-volatile)

140kB

1TB

7,000 X

 

Isn’t it incredible how far we have come? It should be interesting to fill in this table another thirty years from now.

But what really jumped out at me is that, over the last thirty years, the technologies that engineers use to bring designs up and get them working has not essentially changed. Steve Wozniak used visual inspection, multi-meters, low-end oscilloscopes, and other such instruments to bring the initial Apple I to life (and then the Apple II and the II+ and the IIe and so on). The same tools are used today. Even though some aspects of designs have increased tens and hundreds of thousands fold.

I believe that the coming generations of higher-density, higher-speed, and smaller form-factor boards pose a great challenge to the velocity with which designers can get their systems to market. This is based upon the loss of external access to circuit board devices and buses. It will no longer be possible to use traditional, intrusive probe-based technologies to get reasonable levels of coverage for validation, test and debug needs. New tools which are software-based, both external to board designs (host-based) and within them (target-based), will become the norm. Such tools will typically leverage off of powerful instruments that reside within the devices on the board. Examples of these instruments are boundary scan, a processor’s debug port (for processor-controlled test), High-Speed I/O bus BERT and margining instruments, on-board FPGA-based instruments, and many others.

 

Alan Sguigna