April 30, 2007
In a survey I conducted of several firmware engineers, lack of good documentation of hardware was the number one complaint. It is because firmware engineers so heavily rely on the hardware documentation to correctly do their job. Some of the engineers said that wrong documentation is worse than no documentation […]
March 31, 2007
One of the rules of the Extreme Programming design philosophy for software is Never Add Functionality Early. This means that when coding for one product, do not add features or functionality needed for a future product. While this rule does have some merit for software development, it should be applied […]
February 28, 2007
After a presentation I gave at a conference, one of the attendees came up and told me about his ASIC design team that consisted of young engineers. They had completed their design and told him that they were done. He then asked the question, “Six months from now when you […]
January 31, 2007
Late in the development of a new printer, a third-party print engine that interfaced with a block on the ASIC changed its interface behavior. The print engine would quit sending pulses before the block was done with its job, causing the block to hang waiting for more pulses. This behavior […]
December 30, 2006
On an ASIC, my ISR had to write a 1 in one place and a 0 in another place to acknowledge (ack) the interrupt. The hardware engineer I talked to tried to explain how one was an interrupt bit so that is why it needed a 1, but the other […]
November 30, 2006
A common question engineers often wrestle with is how long hardware will take to do a requested task so firmware can take the next step. Engineers implement different designs (both in hardware and firmware) depending on the length of time, and these designs have varying impacts on hardware and firmware […]
October 31, 2006
Several years ago I came across a register that, at first glance, seemed to be a typical register with several read/write bits. Upon closer inspection, I saw that one bit behaved differently, depending on its state and whether I was writing a 1 or a 0 to it. Since firmware […]
September 30, 2006
A few years ago, I was invited to a high-level design review of a new SoC. The proposed design contained an I/O block that needed features added. I successfully convinced them to replace that block instead with an existing block that had the needed features, had seen silicon, and had […]