Use of BeagleBone GPIO for SWD programming

Recently I killed on of SigFox Td1208 device by misprogramming it, destroying the bootloader. In a such situation serial port is not anymore accessible for programming. The use of JTAG port is a necessity. On the TD1208, jtag has been repaced by SWD which is a 2 wires port doing the same thing.

To use this port, you generally need a specific interface. These interfaces like Jlink are expensive (> 300€), some are less like BusPirate (30€). By the way, if you do not have it, you will have to order and wait for it. That’s why I’ve taken the choice of using my BeagleBone black device GPIO to pilot these signal. This code can easily be port to RaspberryPI…

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BeagleBone Black temperature sensor

Here is a quick hack to interface a temperature sensor to a BeagleBone Black unit.

I choose to use a Microship TCN75AVOA component. This SMS component is not really easy to use for prototyping but feasible. This component have a unit cost < 1€ and operate at 5V or 3.3V (as for BeagleBone). A Dip8 version exists. The communication with the CPU is numerical based on a two wire connection type I2C. It measures from -40°C to +125°C on 8b + 4b decimal with +/- 1°C precision.

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BeagleBone Black – configure NTP client

The BeagleBone black do not have Real Time Clock and as a consequence each time you reboot, you’re back at time 0. To get it updated to the local hour, you can configure NTP client (if connected to network) using the following commands:

root@beaglebone:~# opkg update
root@beaglebone:~# opkg install ntp ntpdate
root@beaglebone:~# mv /etc/localtime /etc/localtime.old
root@beaglebone:~# ln -s /usr/share/zoneinfo/Europe/Paris /etc/localtime
root@beaglebone:~# killall -KILL ntpd
root@beaglebone:~# ntpdate
root@beaglebone:~# /etc/init.d/ntpd start
root@beaglebone:~# date
Sun Jun  2 17:41:10 CEST 2013

BeagleBone Black – General Overview

I just got my BeagleBone black device, this is really looking like a Raspberry PI, but personally I found multiple advantage for this card compare to RPI, the first one is related to the embedded 2GB of flash memory that do not require to add external storage. Thank to that, for the first start, you just need to connect the device to your network and a screen and it run ! After about 30s you are connected to a graphical interface and able to surf the web.

The first issue I got with this device is the micro-hdmi connector located really close to the USB connector, due to the current use of an micro-hdmi 2 hdmi adaptor, i’m not able to connect correctly a USB device.I highly recommend to use a micro-hdmi cable instead of a monoblock micro-hdmi to hdmi adaptor for this reason.

By the way, the device is accessible using ssh (root/rootme) and display can be exported easily.

The next part of the article will be about different comparison between BeagleBone and other systems like Raspberry Pi.

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