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Showing posts from July, 2015

RX TX of a USART is easy (right?)

Today I figured it out.
What did you figure out, I hear you say...

I finally resolved a problem with a USART on a STM32F407 board, that was easy to spot if I had just looked closely. I just lost a day in trying to find the fault.

I am working with this board made by Olimex (https://www.olimex.com/Products/ARM/ST/STM32-E407/open-source-hardware)



And connected it using ST-Link interface to my PC.



I connected the SWD pins to the JTAG connector of the Olimex

SWD-pin-1 ------ JTAG-pin-1 (VCC)
SWD-pin-2 ------ JTAG-pin-9 (TCK)
SWD-pin-3 ------ JTAG-pin-4,6,8 (GND) SWD-pin-4 ------ JTAG-pin-7 (TMS) SWD-pin-5 ------ JTAG-pin-15 (TRST) SWD-pin-6 ------ JTAG-pin-13 (TDO)

I connected the serial port (USART6 is pins 3 and 4 of UEXT) of the Olimex to the TX/RX lines of the ST-link (see the green circle)

Then I wrote a program and tested it.
I made sure the PLL of the STM32F407 was running, configured all the needed files.

defined the target cpu in stm32f4xx.h (STM32F40_41xxx)defined the real crysta…

A new generator of PWM controller for AutoJet

Currently I am working on an alternative controller for AutoJet Technologies Spray controller made by Spray systems Inc.
http://www.spray.com/spray_nozzles/pulsajet_nozzles.aspx

I have been working on a more advanced and microprocessor controlled controller, it is intended to be used where the Model 1008 (AutoJet PWM driver modules, aka CP-PMDCT1008-XX) are not advanced enough or easy enough to install and set up.

The 1008-AutoJet device is a pure analog box, it needs to be programmed with potentionmeter/trimmer inside the device and can be controlled externally using industry standard 0..20mA current loop to control frequency of pulses.

The typical application I am looking at is the airless deposition of oils or emulsions used in the production of concrete products.

The oils or emulsions are used as releasing agents with high viscosity, mould release agents designed for the production of expanded concrete blocks. 
Deposition with air-driven nozzles leads to inaccurate placements of d…

Failed to load session "gnome" and how to fix it on Ubuntu

It has been far too long since I wrote something on my blog.
I have been writing on another site : http://blog.wisclub.nl/#home about my CNC machine, and about the mcHF transceiver I am building.

Today I ran into a little problem after updating some packages on my Ubuntu 12.10 VM. (I know this is very old, but I have no choice since a vendor supplied a gcc/uclib toolchain for a specific product exactly on this version of Linux)

However, my X did not start anymore, I got "Failed to load session gnome".

After some digging I realized what had happened, the default X session was set to gnome (which is not really installed) instead of my normal XFCE4 session.

If you know what the problem is, the fix is easy :

$ sudo update-alternatives --config x-session-manager

Then select the correct session manager.


I hope this helps someone from having to search a long time.
Until next time.