skilbjo
Posts: 15
Joined: Fri Mar 04, 2016 9:13 am

RPI 3 + Adafruit Serial Console...

Sun Apr 03, 2016 11:46 pm

Hardware: Raspberry Pi 3, Adafruit 954 USB-to-TTL Serial Cable
Driver: PL-2303 Mac OS X driver v1.6.0
Software: Raspian install from Noobs 1.9 (downloaded today + installed)
Host OS: OS X 10.11.4 (El Capitan)

I installed the driver, but doing an:

>$ ls -l /dev/cu.*
cu.usbserial

>$ screen /dev/cu.usbserial 115200
*blank screen, nothing*

Has anyone able to use the serial cable correctly? How can I tell if the device is correctly listed under /dev ? (I was expecting some vendor numbers but don't see that)

Additionally seems like from some searches that bluetooth is interfering with the pins to connect this? Is there a tutorial to try to understand what this stuff means (UART, pins 10, etc... I'm so lost).

Lastly, is there a workaround to get this running now?

asandford
Posts: 1998
Joined: Mon Dec 31, 2012 12:54 pm
Location: Waterlooville

Re: RPI 3 + Adafruit Serial Console...

Sun Apr 03, 2016 11:55 pm

skilbjo wrote:Hardware: Raspberry Pi 3, Adafruit 954 USB-to-TTL Serial Cable
Driver: PL-2303 Mac OS X driver v1.6.0
Software: Raspian install from Noobs 1.9 (downloaded today + installed)
Host OS: OS X 10.11.4 (El Capitan)

I installed the driver, but doing an:

>$ ls -l /dev/cu.*
cu.usbserial

>$ screen /dev/cu.usbserial 115200
*blank screen, nothing*

Has anyone able to use the serial cable correctly? How can I tell if the device is correctly listed under /dev ? (I was expecting some vendor numbers but don't see that)

Additionally seems like from some searches that bluetooth is interfering with the pins to connect this? Is there a tutorial to try to understand what this stuff means (UART, pins 10, etc... I'm so lost).

Lastly, is there a workaround to get this running now?
If you're asking why your Mac can't talk to the Pi, I suspect you'll get more replies in an Apple forum.

skilbjo
Posts: 15
Joined: Fri Mar 04, 2016 9:13 am

Re: RPI 3 + Adafruit Serial Console...

Mon Apr 04, 2016 1:02 am

Yes, exactly. Although are you suggesting the issue is squarely on the Apple side?

This post would suggest it's a bug/flaw in RPI3, but this stuff is really over my head: http://www.briandorey.com/post/Raspberr ... Workaround

GeoffreyF
Posts: 7
Joined: Sat Jan 09, 2016 4:28 pm

Re: RPI 3 + Adafruit Serial Console...

Mon Apr 04, 2016 1:11 am

The console cable need not even be connected to the PI (any Pi) for it to be visible on the Max as a serial device. If you were to connect the rx to the tx wire (white to green in the adafruit unit) then you should be able to send characters from the Mac and get them back. If this does not work your problem is a Mac problem. Adafruit may have a driver suggested on their site. I'm not a mac expert but I've used the Adafruit product on windows.

If you can see the device on the Mac and the loopback works, you are correct, there are problems with the serial interface and bluetooth. here is how to disable Bluetooth and gain normal pi performance for the serial interface. Add this to the end of config.txt on the PI. (It also seems to speed up Ethernet performance )

1. add "dtoverlay=pi3-disable-bt" to /boot/config.txt
2." systemctl disable hciuart" following the prior line, also in config.txt

If you follow the connection instructions on the Adafruit site, DO NOT connect the 5V red wire. It may not be able to provide sufficient current to boot the Pi3. Instead, provide pi3 power through its microUSB connector as is otherwise indicated.

asandford
Posts: 1998
Joined: Mon Dec 31, 2012 12:54 pm
Location: Waterlooville

Re: RPI 3 + Adafruit Serial Console...

Mon Apr 04, 2016 1:14 am

skilbjo wrote:Yes, exactly. Although are you suggesting the issue is squarely on the Apple side?

This post would suggest it's a bug/flaw in RPI3, but this stuff is really over my head: http://www.briandorey.com/post/Raspberr ... Workaround
Did you have anything running on the Pi that was using the port so that you could talk to it from the Mac?

GeoffreyF
Posts: 7
Joined: Sat Jan 09, 2016 4:28 pm

Re: RPI 3 + Adafruit Serial Console...

Mon Apr 04, 2016 1:15 am

PS "Force Turbo" as your link suggests is probably not the best solution. You are overclocking the PI when you do. There is another solution that sets core speed to 250, also not the best solution, you are then slowing down the PI3 which seems a bit pointless given what the Pi3 is best at.

Try it my way. All three work but with the indicated side effects.

skilbjo
Posts: 15
Joined: Fri Mar 04, 2016 9:13 am

Re: RPI 3 + Adafruit Serial Console...

Mon Apr 04, 2016 7:25 am

Thank you GeoffreyF !!! I am ecstatic. I disabled bluetooth

A bit of google searching... see here: http://www.0xc0de.net/2015/09/getting-a ... -work.html

Trick was... after screen loads up, it is empty. You should just hit "enter" or enter the username "pi". There is no "Login:" prompt.

So in summary:

1. add the two lines in /boot/config.txt (dtoverlay=pi3-disable-bt, systemctl disable hciuart) to disable bluetooth
2. in OS X, screen /dev/cu.usbserial 115200
3. type "pi" and hit enter, even though it's a blank screen

skilbjo
Posts: 15
Joined: Fri Mar 04, 2016 9:13 am

Re: RPI 3 + Adafruit Serial Console...

Mon Apr 04, 2016 8:11 am

Additionally, some resources/troubleshooting tips that will help a fellow noob like me understand a little bit more about what's going on under the hood...

- serial vs parallel, & UART: https://learn.sparkfun.com/tutorials/se ... munication
- TTY: https://en.wikipedia.org/wiki/Computer_ ... _terminals
- seems to be no difference between cu.* and tty*... so screen /dev/tty.usbserial should work.
- TTY are login shells... except for ttyAMA0 with is the UART bus, so no need touching that (I think?).
- no worries if the vendor name doesn't come up (/dev/cu.PL2303-blah); /dev/cu.usbserial works just find.
- if you can get the cable to work just try unplugging and plugging it back in.. there's a microcontroller in the cable and maybe it failed and just needs a restart!

Philmod
Posts: 1
Joined: Fri Jun 03, 2016 6:03 pm

Re: RPI 3 + Adafruit Serial Console...

Fri Jun 03, 2016 6:06 pm

skilbjo wrote: 1. add the two lines in /boot/config.txt (dtoverlay=pi3-disable-bt, systemctl disable hciuart) to disable bluetooth
How can I make this modification if I don't have a keyboard/monitor? I rely on the Console Cable.

Thanks,
Philmod

wulvyrn
Posts: 1
Joined: Sat Jun 18, 2016 4:51 pm

Re: RPI 3 + Adafruit Serial Console...

Sat Jun 18, 2016 4:53 pm

you'll have to mount the sd card in a computer, make the changes and unmount it and put the sd card in the pi and boot.

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