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Showing posts from February, 2010

Moving code from ESP8266 to ESP32

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A while ago I made a mashup of Dan Royer's code CNC 2 Axis Demo with my own code for trapezoidal motion stepper and servo control for ESP8266.

I assumed porting the code to the ESP32 would be trivial, and that was true for the most part: changes like library name being Wifi.h instead of Wifi8266.h were not a problem. UDP now does not like multicharacter writes but you can use print instead. So far so good.

However, when it came to the interrupt code I was stuck with the stepper interrupt causing an exception sometimes. And to make things weirder, the servo interrupt worked flawlessly (both of them had the IRAM_ATTR directive if you ask me).

Going little by little, I could narrow down the culprit to a floating point operation during the interrupt, that would cause problems sometimes but not always. Browsing around I found this post. Where the solution was simple: do not use floats within the interrupt routines but doubles. The reason was the float calculation would be performed by…

Trouble on Googleland

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Just as Google seems to be facing some trouble with EU regulators, my (till now) trusty Gmail account started to give me trouble too.

I started a thread on Gmail help forums a week ago complaining of a sudden and weird problem. It turns out that many people are reporting a similar problem.

A cool feature of Gmail is that you can fetch emails from other accounts supporting POP3 access. It has been working great for a long time, with the added benefit of using Gmail's spam filtering on that other account's emails.

Unfortunately, starting two weeks ago, Gmail stops fetching emails from these other accounts for no good reason. While a fix has been posted: save the affected account settings again, this fix does not last long and problem eventually reappears.

While it might look like certain ISP is to blame, given the different and varied error reports it looks much more likely that trouble is in Gmail systems.

Wake on lan

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Recognizing the big amount of energy being wasted at my university, a system for waking up a computer has been set up. In the past many people, including myself, had no other choice but to leave the computer on if you might want access it remotely (as directed-broadcast is not allowed on campus' network, there was no way to send a Wake-On-Lan magic packet from outside of campus).

The new system put in place allows users to wake up their computer from the university intranet, which is a big plus. Alternative systems were available but only worked on certain subnets and you need to know you computer's MAC address (something I have to tell you I've never been able to memorize).

However, and there is always a catch, I realized my computer (an ASUS P5G33) did not seem to accept the wake-on-lan feature. I am quite doubtful about following the advice I read on a forum, even more if it requires reflashing my motherboard BIOS with a firmware many tools refuse to accept. However, I d…

What a disappointment

As I mentioned a few days ago a talk by Richard Stallman was held on campus and I decided to go. The talk was along the lines of the four freedoms (kind of Stallman's version of Asimov's three laws of robotics). But almost at the end of the talk and before the questions he invited to another unannounced speaker who had some rants about the university.
Everyone is entitled to her own opinion but this was not the reason why I was there so I left. I cannot comment on that other speaker merits but it felt like a commercial in the middle of the talk (and keeping you there from leaving if you wanted to listen the question).
Should that individual have announce his speech people might have decided whether they wanted to attend or not, but the way it was done it felt like a trap. What it may be relevant here is that the university was providing a conference hall for free based on the idea Stallman's speech was of interest for our student and faculty.
As expectation was building up…