The walking LED

I started to work on the SOM with Romain a few weeks ago. My objective is simple: we need to be able to test our modules while we wait for our PCBs.

It’s alive !

For this purpose, I took my favorite necromancy book and proceeded to revive CyL3D.

I used this opportunity to get familiar with the tools we use to program the FPGA. I forked the reference project from Aries and tried to communicate with the drivers using only the FPGA.

However I was not able to control the drivers properly, more debugging has to be done. In order to accomplish this debugging, I need to control the our modules using the HPS.… Read more

Tryna catch me drivin’ dirty

We decided to use the TLC5957 LED driver of Texas Instruments with Broadcom RGB LEDs: ASMB-KTF0-0A306.


Brightness control

First, we have to determine the maximum current which will be used. The 3 colours of the RGB LEDs can get a 20 mA input current max and the driver can handle 20mA sink current max. So we choose a maximum current of 20mA.

We decided to configure the driver with the maximum value for the Brightness Control (BC) (and by consequence, the maximum gain) to provide the intensity to go over 20mA. So we have to choose a value of BC equals to 7.… Read more

Going back and forth the H-Bridge

We need to be able to drive our little magnet marbles and flip them according to a magnetic field direction or the opposite one. To do so current must be able to flow both ways through our self-inductances. Moreover we’re going to need current’s intensity of a much higher value than what is able to flow out of or flow in the GPIO.

One way to do so, is to use a H-Bridge as we can see on this site that we’ve already mentionned in an earlier post.

What’s an H-Bridge

Basically an H-Bridge is a electronic circuit built with drivable switches in a way that allows us to flip the voltage on a load and thus allows us to flip current polarity.… Read more