Closed charlespax closed 8 years ago
Without any modification these are typical SW_A keypresses:
I tossed a 0.1 uF cap between SW_A and GND. All presses look like this:
Put a 0.1 uF cap on each switch.
There is a problem during power on. There is a quick spike in power, probably transferring from bootloader to firmware. This is triggering the record function such that the device is already recording when the screen comes on.
In the screenshot below a 0.1 uF installed SW_B. The red area shows the device powering down. The green area is the device powering on. There's also a few button presses to the right.
Here is the same process with a 0.47 uF cap installed. There is still a small spike, but it is not triggering the record function.
I think a good approach here is to try to fix this int he bootloader. Maybe that pin is being brought high or left floating.
It's only causing a problems when connected to the Oscope.
Okay. I have to add caps to between each switch and GND. Populate the 10 pullup resistors. Otherwise the two bootloader delay buttons are close to ground and the device will delay.
I have put the latest revision on the scope and have not seen this issue. I think maybe there was either a software problem of the issue was due to the soft power logic circuit, which has been changed. Closing issue.
The switches seem to bounce. See https://github.com/PaxInstruments/t400-firmware/issues/189 for background. Let's figure this out.