Posts

Showing posts from January, 2010

Moving code from ESP8266 to ESP32

Image
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…

VMware did it again!

Image
I've upgraded my main desktop machine to Ubuntu 9.10 and one of things I need to get going is VMware's VM Player. I've been pleasantly surprised to discover that the new 3.0.0 version of wmplayer does include a new feature to create new virtual machines. While I had no complaint using easyVMX site I am extremely happy of having this new feature, previously only available on VMware Workstation product.

So, thanks a lot VMware.

University Talk

Image
Next week, Richard Stallman will give a talk at UPV campus (Conference Hall at building 1H) on Thursday February 4th, at 5:00pm.

Richard has already visited UPV before and can speak Spanish, so I guess that is what he'll use. His views about the software development and ethics are all but conventional. But now that the free sofware concepts have spread open wide many people share many of his points of view.

Not sure, however, if Richard still thinks the Copyright Levy (canon digital) we have in Spain now is fare.

Temperature logger needed

Image
Heating and air conditioning are the cause of much trouble on campus. Yesterday I was asked to make a decission as it was believed one of our buildings was too hot because of the sun. But, as I'd like to make my decissions based on facts I decided to setup a temperature logger. As heating is off on Sunday (but Sun is only off at night) I'll be able to compare the temperature profile of Sunday against all the other days when the heating is on.

Unfortunately no data logger was available so I set up my own one using three simple elements: An arduino board (actually it was an iDuino I had lying around) a Dallas Semiconductor (actually now part of Maxim IC) DS18B20 digital temperature sensor and a PC.

I adapted some code I borrowed from Nuelectronics to read the temperature and I transimted to the PC over the serial port. On the PC side (my office PC is running Windows) I had to program it using VisualStudio, so I created a simple VisualBasic program, whose only purpose is to add the…

New year new toys

Image
During the last holidays I've been playing with a new Linux board that I've found quite interesting. It is an open project developed by a Spanish company which in turn enriched the Beagle Board idea with a lot of cool hardware: wifi, Ethernet, Bluetooh, RS-485, LCD controller, etc. They both share many other interesting peripherals as 3D accelerated graphics board featuring HDMI output, microSD memory socket, audio I/O and DSP,USB port, JTAG port etc.

The so called IGEPv2 (not sure it is a good name as I find it quite difficult to remember, maybe I'm aging) is a cool piece of hardware that comes with a Linux distribution name Poky and it based on an ARM Cortex-M8 processor running at 720Mhz that needs less than 3 watts for the whole system. It can run Ubuntu and many other ARM-based Linux distros. And it costs 140 Euros, which I reckon it is a sweet price.

Put it together with a large HD display and you have a point of information for the public. You may even hide the card i…

International version of Kindle DX

Image
It seems you can pre-order an International version of Kindle DX from Amazon. Same price as US version.
In another front there seems to be more players to the "larger" ebook format, the Skiff and the QUE showing off. But, while some demo new ideas, it seems Apple is about to surprise us (ok, maybe not) with a real device by the end of the month.