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| caraboot unreliable with USB hub https://www.8devices.com/community/viewtopic.php?f=13&t=917 |
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| Author: | karlp [ 09 Oct 2015, 17:16 ] |
| Post subject: | caraboot unreliable with USB hub |
| Author: | karlp [ 12 Oct 2015, 13:08 ] |
| Post subject: | Re: caraboot unreliable with USB hub |
Somewhat related, what's internal on the Carambola2 module for the JumpStart pin? Turns out we have a 10k pullup on the button, rather than 4k7, and on a few boards this seems to result in the bootloader always thinking the button is pressed. When the board is unpowered, it's a clear working button shorting to ground when pressed/not pressed, but when powered, I'm seeing 1.5V on the JS pin, which is clearly going to be "exciting" with thresholds |
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| Author: | karlp [ 12 Oct 2015, 14:10 ] |
| Post subject: | Re: caraboot unreliable with USB hub |
On that jumpstart pullup, switching the button pullups from 10k to 3k9 fixed issues with the button being detected reliably. (4k7 in the dev board schematics, but didn't have that available for some reason) There's no mention on what's behind that pin on the module, and I'm a little surprised that the pullup needed to be that much stronger to work! |
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