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by Renate
Mon Apr 08, 2019 12:10 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Soldering the USB port - does not work
Replies: 16
Views: 1039

Re: Soldering the USB port - does not work

Just a question out of left field...

Are you sure that your short little cable isn't an OTG cable?
(That would have the ID grounded at the plug going into your red board.)
by Renate
Mon Apr 08, 2019 12:04 am
Forum: Raspbian
Topic: Very slow shutdown or reboot on Pi 3
Replies: 6
Views: 1805

Re: Very slow shutdown or reboot on Pi 3

I know this is an old post, but here's the answer anyway. A 90 second delay should tell you that some daemon has been asked nicely with SIGTERM to stop. It has ignored it and after 90 seconds it got SIGKILL. One way to catch this is with a camera on the shutdown screen. Maybe it's YOUR daemon that i...
by Renate
Thu Apr 04, 2019 11:39 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C multiple messages broken on i2c_bcm6835?
Replies: 0
Views: 194

I2C multiple messages broken on i2c_bcm6835?

Linux zero 4.14.98+ #1200 Tue Feb 12 20:11:02 GMT 2019 armv6l GNU/Linux I'm using C & ioctl & struct i2c_rdwr_ioctl_data to send transactions. A write/read (2 messages) doesn't seem to work correctly (110 timeout); I have to do it as two separate ioctls when using the default i2c_bcm2835 driver. Thi...
by Renate
Thu Apr 04, 2019 11:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: software i2c & 5v slaves
Replies: 4
Views: 389

Re: software i2c & 5v slaves

I never lose any sleep mixing 3.3V and 5.0V I2C devices. Of course you have to make sure that your pullups (including internal pin pullups) only go to the lower voltage. If you don't do that, the pullups will pull up a lower voltage input past its supply voltage, backfeeding it. If you see Vcc on yo...
by Renate
Wed May 16, 2018 10:31 pm
Forum: Advanced users
Topic: Trouble getting modbus over RS485 connecting to GPIO
Replies: 5
Views: 1684

Re: Trouble getting modbus over RS485 connecting to GPIO

You'd really need to write a driver to have this work. For one, you usually only care in serial transmission if you have room in your buffer to stick another char. In the case of switching direction for RS-485 you have to watch when the last bit is shifted out. I looked into this whole thing and dec...
by Renate
Sun Mar 22, 2015 9:08 pm
Forum: Advanced users
Topic: USB back-powering
Replies: 0
Views: 405

USB back-powering

I've seen a few things here and there discussing power switching and using back-powering USB hubs to power the Pi instead of using the power input on the micro USB connector. Depending on your viewpoint, this is pointless, dangerous, stupid or useful. I'm not fond of micro USB connectors as a power ...

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