app notes and competence

designing development boards which the rest of the world would have looked at for inspiration and guidance. I was 31 and trust me, the world has desig ned better Altera based PCBs as a result of not using my designs as referen ce material.

was terrible and made me wonder yet again who writes this stuff. It has be en replaced in September 2019 with the way that Howard Johnson recommended many, many years ago, ie plonk down the biggest capacitance in the smallest package.

t know probably.

First you complain about your own work being crap, then you appear to be co mplaining about Xilinx work. I'm not sure if you are saying Howard Johnson 's work is good or bad.

What are you trying to say with all this?

My work wasn't crap, but at the time I had only ever put one FPGA onto a PC B (lots of DSPs and Processors though) and as an industry we look to the de signs of the manufacturers as the best way to do things. Clearly if I had p assed at the third interview the world would have used the output of an ine xperienced FPGA guy as the way to design with them.

Howard Johnson was hired (in some manner) by Xilinx to help them as Signal and Power integrity became an issue and I have met him and have enormous re spect for him. Xilinx UG583 was first issued in 2013 and it has taken them six years to change their capacitor recommendations from something which I thought was a bit silly and which I slightly ignored to exactly what Dr Joh nson worked out with them many years ago.

I'm in the middle of having a very expensive board laid out and I just want ed to rant about the quality of the advice that we all have to work with.

Rob

designing development boards which the rest of the world would have looked at for inspiration and guidance. I was 31 and trust me, the world has desig ned better Altera based PCBs as a result of not using my designs as referen ce material.

was terrible and made me wonder yet again who writes this stuff. It has be en replaced in September 2019 with the way that Howard Johnson recommended many, many years ago, ie plonk down the biggest capacitance in the smallest package.

t know probably.

I am using a very nice part at the moment from Linear Tech. I am finding t hat they have a feature that they go to great lengths to explain. What the y do not explain is how to disable/not use this feature. I have had to spe nd days convincing myself that I can disable this feature (go against some of the wording in the data sheet).

PCB (lots of DSPs and Processors though) and as an industry we look to the designs of the manufacturers as the best way to do things. Clearly if I had passed at the third interview the world would have used the output of an i nexperienced FPGA guy as the way to design with them.

l and Power integrity became an issue and I have met him and have enormous respect for him. Xilinx UG583 was first issued in 2013 and it has taken the m six years to change their capacitor recommendations from something which I thought was a bit silly and which I slightly ignored to exactly what Dr J ohnson worked out with them many years ago.

nted to rant about the quality of the advice that we all have to work with.

Howard Johnson seems to know the basic facts of high speed circuit design, but he's a rotten teacher. I bought his "Black Magic" Book on Win Hill's re commendation here, and found it unhelpful - I was reminded of E.C. Snelling 's book on soft ferrites, which eventually presents pretty much all the inf ormation you'd ever need, but in a way that makes it very difficult to extr act the specific bits of information you need to solve any specific problem - another pedagogic disaster.

Even John Larkin has been rude about Howard Johnson - if you think his advi ce is good, you must have rather low standards.

HoJos books are half OK and half nonsense. If you can tell which part is which, you don't need the book. The current UG583 is a similar mix.

HoJo has brain-damaged a generation of engineers. One of my customers recently reviewed one of our PC boards and started spouting about "return currents" and insane bypassing. It was embarassing.

Most big chips now have a lot of on-silicon bypassing [1]. Nobody specifies or mentions the on-chip stuff, so I measure it. I must average a tenth of the caps than appnotes recommend. And I've never used too few caps.

The PCB planes are the best capacitors around, and they are free. The discrete caps don't matter much.

See, you didn't have to buy a book.

We don't generally put caps on the bottom of the board, and we keep topside caps a distance away from the BGAs so we can slide our BGA inspection microscope head between. Always works.

IC data sheets are, in general, a disgrace. They often skip obvious issues and sometimes outright hide hazards.

Support requests now mostly go to a forum, where users can share their discoveries. I think it's hard to get decent support people (the good ones get hired away fast) and they want to insulate the chip designers from rabble like us.

I was thinking of starting a web site icbugs.com or something. That would be fun.

Wow, I got a few of them! But, not sure any of these chips are really relevant anymore.

Jon

He should have stuck to making grilled cheese sandwiches!

Howard D. Johnson's design prototype Canton, MA restaurant location sadly closed sometime in the early 2000s, there's a Dunkin' Donuts coffee shop and some "upscale" bar & grill in the building, now.

I wish we had DD out here in the West. Their Boston Cremes are the best.

And the nearest Chick Fil A is 40 miles away.

Engineering makes a boy hungry.

DD is one of those coffee shop chains where most things on the menu are good, except for the coffee. It seems traditional in NE to drink it with a lot of cream and sugar which makes it palatable but might as well have a milkshake at that point.

there's one right down the street I don't buy that company's stuff, though, never had it and guess I never will.

looks like they interrupted the President's lunch to have a press conference lol:

there were bowls of extra sauce

the point here is that many semi-pro athletes grew up poor and this is their one shot in life to rise above their former station, people who grew up poor and then "make it" in my experience tend to not have a lot of nostalgia for the only cheap fast foods they could afford when poor

Sort of like how a proper first date with a woman who grew up working class is a fine restaurant and the art museum while a proper first date with a woman who is from a very wealthy family is McDonalds and a monster truck rally.

Serving fast food to Congress regularly and making them take the bus everywhere would be a policy I could get behind, though.