I have a robot that is no longer working.
I have been downloading to the AXE401 shield base (28X2 picaxe chip) on and off about 30 to 40 times since the board was new last October. see http://www.picaxe.com/docs/axe401.pdf page 4
The motor drivers etc, are provided by an instant robot board: AXE408 - see http://www.picaxe.com/docs/axe408.pdf
Today it stopped working.
On inspection the following commands were not seeing the voltage change (measured with a voltmeter = 5volts / 0volts)
on Shield pin S.0 also known as C.7
when handling the circuit board to see if there was an obvious short circuit, and to measure the actual voltage on S.0, my finger brushed against the "VR" pin, which is also pin A.3 according to the PDF document.
This touch caused the robot to start.
using a simple debug loop,
I saw that b2 was not responding to the pushbutton, but was responding to the "Vref" pin,
and b3 was responding to the a.3 pin on the left of the circuit board 3rd one down in the analogue inputs. (see AXE401 pdf page 4)
my question is this?
**** Has anyone else seen this kind of failure mode?. ****
I will replace the 28X2 chip as soon as I can, and post my findings.
This input-swapping is the only fault I have found with the robot.
It reads its other inputs, and controls its motors quite happily once it has seen its start pushbutton signal.
(I now touch the Vref pin to get it started!)
I have been programming PICAXE chips for many years, and apart from the loss of downloaded program during a period of high solar activity about 3 years ago, I've never seen anything like this.
Regards
John Fisher
I have been downloading to the AXE401 shield base (28X2 picaxe chip) on and off about 30 to 40 times since the board was new last October. see http://www.picaxe.com/docs/axe401.pdf page 4
The motor drivers etc, are provided by an instant robot board: AXE408 - see http://www.picaxe.com/docs/axe408.pdf
Today it stopped working.
On inspection the following commands were not seeing the voltage change (measured with a voltmeter = 5volts / 0volts)
on Shield pin S.0 also known as C.7
Code:
WaitPushbutton:
do : loop until pins.0 =1 ' wait till pushbutton pressed
do : loop until pins.0 =0 ' wait till released
return
This touch caused the robot to start.
using a simple debug loop,
Code:
do
b2 = pinc.7
b3 = pina.3
debug
loop
and b3 was responding to the a.3 pin on the left of the circuit board 3rd one down in the analogue inputs. (see AXE401 pdf page 4)
my question is this?
**** Has anyone else seen this kind of failure mode?. ****
I will replace the 28X2 chip as soon as I can, and post my findings.
This input-swapping is the only fault I have found with the robot.
It reads its other inputs, and controls its motors quite happily once it has seen its start pushbutton signal.
(I now touch the Vref pin to get it started!)
I have been programming PICAXE chips for many years, and apart from the loss of downloaded program during a period of high solar activity about 3 years ago, I've never seen anything like this.
Regards
John Fisher