G
[email protected]
- Jan 1, 1970
- 0
I have a circuit that acts stangely enough when I connect a ground
connection of a scope probe to it.
The circuit has a TI DSP 280x Series Processor, an Isolated Switching
Power Supply All the AD inputs and GPIO are isolated to the AC Line. In
my evaluation of the performance of the circuit I found that the
systems is able to perform accordingly when the scope probe ground is
connected to the circuit. I don't even need to have the probe connected
to the circuit, just the ground. The probe must be connected to the
scope in order for this to happen. If the this connection is not made
the device sometimes delays to react to the input accordingly. I'm
using a portable scope (THS720 Tektronix with isolated ground
connections). The behavior also happens with benchtop scopes that are
not isolated.
I have all my unsuded GPIO set as inputs and with internal pullups
enabled to avoid any parasitic effects.
This is a multi-layered board with Separated Power Planes (3.3V and
1.8V) and a single ground plane.
Any suggestions on where to start?
Thanks for all your help on this in advance.
gt5513e
connection of a scope probe to it.
The circuit has a TI DSP 280x Series Processor, an Isolated Switching
Power Supply All the AD inputs and GPIO are isolated to the AC Line. In
my evaluation of the performance of the circuit I found that the
systems is able to perform accordingly when the scope probe ground is
connected to the circuit. I don't even need to have the probe connected
to the circuit, just the ground. The probe must be connected to the
scope in order for this to happen. If the this connection is not made
the device sometimes delays to react to the input accordingly. I'm
using a portable scope (THS720 Tektronix with isolated ground
connections). The behavior also happens with benchtop scopes that are
not isolated.
I have all my unsuded GPIO set as inputs and with internal pullups
enabled to avoid any parasitic effects.
This is a multi-layered board with Separated Power Planes (3.3V and
1.8V) and a single ground plane.
Any suggestions on where to start?
Thanks for all your help on this in advance.
gt5513e