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This page contains informatton about bugs found and the various revisions, with their changes. It also offers new revisions but the user is fully responsible for uploading a new revision.

Revision 2.6

Released April 26, 2015. Full release: tested.
Gertbot upload image rev 2.6    Gertbot manual 2.6
Gerbot GUI windows 2.6    Gerbot GUI Linux 2.6
C-drivers 2.6 (zip)    C-drivers 2.6 (tgz)     Python-drivers 2.6 (zip)    Python-drivers 2.6 (tgz)   


DCC programming
In DCC mode it was not possible to program some DCC controllers. This was due to the fact that there were idle packets between the commands. Even when setting the ‘no idles’ control bit there would still be at least one idle packet. In revision 2.6 idle packets are complete suppressed when the ‘no idles’ control bit is set. Also there is now at least a 20ms gap after a reset packet.

Quadrature go-to & sync
In revision 2.5 the "sync" command could not be used with the quadrature “go-to” command, This is now implemented

Quadrature limits and normal run
Previously a normal “Start Brushed motor” command would start the motor even if the position was beyond the quadrature limits. The motor would be stopped soon but that takes a short time. Thus each time the “Start Brushed motor” is given the motor would move a bit further past the limit. Now if a motor is at or past the quadrature limits, a “Start Brushed motor” command will be ignored.

Revision 2.5

Released March 2015 to manufacturer


Open collector settings
When setting the output levels, the open collector pins would revert to input mode. The fix in 2.4 was not working. This is now fixed (and tested).

Reverting from DCC mode
When switching to Brushed mode from DCC mode the PWM of the brushed motors would no longer work. This is now fixed.


Support for Quadrature encoders
The support for quadrature encoders is the biggest change to the rev 2.5 software. For details read chapter 9 of the Gertbot manual 2.6.

Revision 2.4 (pre-release)

Released February 2015. Code and manual only. Pre-release to allow user benefit of bug fixes.
Retracted 26 April with release 2.6 as release 2.4 was untested. The fixes listed below are still valid for release 2.5 and 2.6.


Linear-stop command
Start/stop Brushed Motor (0xA0 0x06 0x50)
The ‘stop’ version of this command is supposed to also stop stepper motors. This was not working in release 2.3. (It was working at first, but I broke it when I implemented ramping) Fixed in release 2.4.

Stepper motor take steps (0xA0 0x08 0x50)
The channel-2 stepper motor was taking the first step in the previous direction. Thus a command
        [left 4 steps]
followed by
        [right 4 steps]

Would execute as :
        step left 4 times
followed by
        step left 1 time
        step right 3 times
Fixed in release 2.4.

Open drain and outputs
When setting the output pins the open drain status would always go back to ‘off’.
Fixed in release 2.4.


Filtered end-stops.
For brushed mode, the end-stops were implemented in an interrupt service routine making them extremely fast. Practice has shown that the end-stop signals where likely to have glitches on them especially with long wires and noisy motors. The glitches would still pass through heavy R-C filtering. Therefore the revision 2.4 now supports end-stop glitch filtering in software. The filtering is done using an integrator with a 1-millisecond sampler. The user can set an integrator limit between 1 and 255. For details see revision 2.6 of the Gertbot manual.

Set short/hot.
The short/hot settings where combined with the end-stop settings. The new end- stop command no longer has information about short/hot, thus a new command to set the short/hot mode has been added. See manual for more information

Baud rate.
Some user wanted a higher data transfer rate. The version 2.4 supports five baud-rates. NOTE for a (yet) unknown reason only 3 of the five baudrates work between the PI and the Gertbot. All five baud rates work with a USB converter and the Gertbot. All See manual for more information

Revision 2.3

Revision 2.3 was the first production revision.