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Circuit Sword Bluetooth
Posted: Wed Jun 27, 2018 2:27 pm
by dasfool
Has anyone been able to get Bluetooth working with Kite's Circuit Sword?
Is this still the most up to date information?
Kite wrote:Hardware wise it does [have bluetooth] but I haven't enabled/tested it as I don't think it's as simple as just 'turning it on' so if someone wants to give it a go then please let me know how it goes (this might be a starting place
https://github.com/lwfinger/rtl8723bs_bt) as it is connected to the hardware serial port of the Pi
Re: Circuit Sword Bluetooth
Posted: Thu Jun 28, 2018 2:21 am
by kite
I've not made any attempt to work on bluetooth, but if you want to give it a go, the GPIO pins used and wired up already to the module are:
GPIO32 - TXD -- > RX on module
GPIO33 - RXD --> TX on module
CTS and RST have not been connected at all, hopefully that's not a problem.
It's the same module used on the CHIP so this may also help:
https://github.com/NextThingCo/rtl8723ds_bt
This looks interesting too:
https://github.com/Miouyouyou/MyyQi/issues/7
There appears to be a guide (altho for the PIN64) here:
https://nanite.co/tag/rtl8723bs/
Re: Circuit Sword Bluetooth
Posted: Mon Oct 01, 2018 12:06 pm
by AntFJ
kite - you mentioned in another thread pins on the board for an extra usb... can you point these out? I want to add an internal bluetooth dongle via usb. I'm not entirely sure if it will work but I want to give it a try.
Re: Circuit Sword Bluetooth
Posted: Mon Oct 01, 2018 2:49 pm
by kite
AntFJ wrote: ↑Mon Oct 01, 2018 12:06 pm
kite - you mentioned in another thread pins on the board for an extra usb... can you point these out? I want to add an internal bluetooth dongle via usb. I'm not entirely sure if it will work but I want to give it a try.
Yeah, it's slightly different depending on which version you have.. but both are right next to the USB C charging port:
- 1.1E: There are some solder pads (DP, DM, GND) in that area, where it looks like a chip is meant to go.
- 1.2A: There is a 4pin JST header in this place with DP, DM, GND, POWER
Re: Circuit Sword Bluetooth
Posted: Mon Oct 01, 2018 3:15 pm
by AntFJ
Perfect I'll take a look when the board arrives in a couple weeks
kite wrote: ↑Mon Oct 01, 2018 2:49 pm
AntFJ wrote: ↑Mon Oct 01, 2018 12:06 pm
kite - you mentioned in another thread pins on the board for an extra usb... can you point these out? I want to add an internal bluetooth dongle via usb. I'm not entirely sure if it will work but I want to give it a try.
Yeah, it's slightly different depending on which version you have.. but both are right next to the USB C charging port:
- 1.1E: There are some solder pads (DP, DM, GND) in that area, where it looks like a chip is meant to go.
- 1.2A: There is a 4pin JST header in this place with DP, DM, GND, POWER
Re: Circuit Sword Bluetooth
Posted: Mon Oct 01, 2018 3:48 pm
by kite
Ah in that case yours will be version 1.3A, which is the same (in this regard) as 1.2A
you can use the included JST cable for it, and they're easy to buy online (JST SH 4 pin)
Re: Circuit Sword Bluetooth
Posted: Sat Oct 06, 2018 5:21 pm
by ThompsonTinkers
I've actually managed to get this working! No guarantees that I've got it working the right way, though.
First, add this to /boot/config.txt:
Code: Select all
force_turbo=1
enable_uart=1
dtoverlay=uart0,txd0_pin=32,rxd0_pin=33,pin_func=7
Next, go into raspi-config -> Interfacing Options -> Serial and disable the login shell on serial, but enable the serial port hardware.
And reboot.
When you come back, it's a good time to checkout and compile
https://github.com/lwfinger/rtl8723bs_bt
I found that the included start_bt.sh script didn't do a good job of guessing the serial port device on my Circuit Sword. Here's a hardcoded version:
Code: Select all
#!/bin/bash
TTY="/dev/ttyAMA0"
echo "Using device $TTY for Bluetooth"
if [ ! -f /lib/firmware/rtl_bt/rtlbt_config ];
then
mkdir -p /lib/firmware/rtl_bt/
cp rtlbt_* /lib/firmware/rtl_bt/.
fi
./rtk_hciattach -n -s 115200 $TTY rtk_h5 > hciattach.txt 2>&1 &
Now run that, and check dmesg. You should see something like:
Code: Select all
...
[ 54.528820] uart-pl011 3f201000.serial: no DMA platform data
[ 55.427986] Bluetooth: Core ver 2.22
[ 55.428234] NET: Registered protocol family 31
[ 55.428242] Bluetooth: HCI device and connection manager initialized
[ 55.428291] Bluetooth: HCI socket layer initialized
[ 55.428309] Bluetooth: L2CAP socket layer initialized
[ 55.428365] Bluetooth: SCO socket layer initialized
[ 55.438117] Bluetooth: HCI UART driver ver 2.3
[ 55.438145] Bluetooth: HCI UART protocol H4 registered
Caveats so far:
- This doesn’t run at boot, so you have to start_bt.sh each time you want to use it.
- The RTL8723 module doesn’t seem to reboot at the same time as the CM3. If it can’t sync (check hciattach.txt) try power cycling the circuit sword.
- I’ve installed a few different bluetooth utilities, and I have not yet tried this set of instructions from a stock install. I might have missed something.
I’ll leave configuring bluetooth peripherals as an exercise to the reader (for now). I’ve managed to get a bluetooth keyboard paired through bluetoothctl, but I have not tried any other type of hardware.
Re: Circuit Sword Bluetooth
Posted: Sun Oct 07, 2018 12:33 am
by kite
NICE! I got something similar but it seems i missed out the console over serial thing. I'll have an experiment too and see if there's anything to make it more reliable.. i can then include those fixes as default in the image (providing it works enough!)
Re: Circuit Sword Bluetooth
Posted: Mon Oct 08, 2018 3:10 am
by kite
Just wanted to reply saying that I've tried it out and works
You can omit the 'force_turbo=1' because UART0 is the hardware one, not the CPU controlled software one (which would require that line).
Ok so the following statement is true with regards to bluetooth:
If you issue a 'reboot' command, when the system comes back up the bluetooth radio will not work. You must do a full power cycle (main power switch == OFF!).
The reason is that the 'reset' pin for the radio is pulled up to 3.3v, meaning that it doesn't get 'reset on reboot'. I'm working on a slight hardware mod to fix this which will involve soldering a wire to a pin so that on a reboot the radio is reset properly
I haven't found the best pin to use yet (basically need a pin that on boot pulls to GND and then goes floating/high). It's important that this happens RIGHT at power on because it also resets the wifi side of the chip, which we really shouldn't do after all drivers have loaded etc
I will look to add this to the Circuit Sword image by default, and when I have the hardware mod I'll post it and also update the design files so that future versions 'just work'
Re: Circuit Sword Bluetooth
Posted: Mon Oct 08, 2018 7:50 pm
by ThompsonTinkers
It looks like rtk_hciattach connects at 115200 bps. Then as part of configuring the module, it raises the bitrate. On mine, it sets it to 4928002 bps [1]. I haven’t tried writing it, but I suspect it might be possible to reconnect at the higher rate on a warm boot.
I wrote a systemd file to get this up and running at boot.
Code: Select all
[Unit]
Description=RTL8723 Bluetooth Support
[Service]
ExecStart=/root/rtl8723bs_bt/start_bt.sh
[Install]
WantedBy=multi-user.target
Alias=rtk-attach.service
And updated start_bt.sh to be a little less tied to running from a specific directory.
Code: Select all
#!/bin/bash
TTY="/dev/ttyAMA0"
LOGFILE="/var/log/hciattach.log"
BASE="/root/rtl8723bs_bt"
echo "Using device $TTY for Bluetooth"
if [ ! -f /lib/firmware/rtl_bt/rtlbt_config ]; then
mkdir -p /lib/firmware/rtl_bt/
cp ${BASE}/rtlbt_* /lib/firmware/rtl_bt/.
fi
"${BASE}/rtk_hciattach" -n -s 115200 "$TTY" rtk_h5 > "$LOGFILE" 2>&1
I’m not a big fan of how it copies the firmware in each time. Do you know if there’s a specific reason to check for that on each boot?
[1]: I think the 2 on the end places a lot of trust in the precision of the system clock.
