From 2c1bba5a518a0907fe7d23f00501284d4e1bb356 Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Tue, 30 Jun 2026 18:00:28 +0000
Subject: [PATCH 01/16] discussion on the IMU

---
 imu.md | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 imu.md

diff --git a/imu.md b/imu.md
new file mode 100644
index 0000000..74efd54
--- /dev/null
+++ b/imu.md
@@ -0,0 +1,13 @@
+# The Intertial Measurement Unit
+
+As of 2025, we started using an AliExpress version of https://wolles-elektronikkiste.de/en/icm-20948-9-axis-sensor-part-i
+
+This has an unmarked jumper on the back.  Joe believes that it shorts the VDDIO and VDD pins in order to allow it to be used with 1.8V devices.
+
+Marcel has tested that the pads connect to both of those pins.
+
+The IMU runs on 1.8V, but our Pi has GPIO voltages of 3.3V.  Marcel reports that students in 2025 had no problem using it as long as AD0 and NCS were connected to VDD.
+According to the specification, the maximum pin voltage is VDDIO+0.5, which would put it at 2.3, a whole volt below 3.3.  On his board, he connected the pins to 3.3V though a 10K resistor to protect it from overcurrent.
+
+For I2C at least, it appears that we are saved by the fact that it is open-drain.  Each device communicates to the master by pulling lines low, which should work with both voltages.
+

From 3ef2ca02a62ab715b6e262c4b29cb27f14d6ee66 Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Thu, 2 Jul 2026 10:29:54 +0000
Subject: [PATCH 02/16] test if MyGadget already exists

---
 Scripts/gadget.sh | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/Scripts/gadget.sh b/Scripts/gadget.sh
index 52e1ca3..86514d4 100755
--- a/Scripts/gadget.sh
+++ b/Scripts/gadget.sh
@@ -4,17 +4,22 @@
 # https://pip-assets.raspberrypi.com/categories/685-app-notes-guides-whitepapers/documents/RP-009276-WP/Using-OTG-mode-on-Raspberry-Pi-SBCs
 
 # Is the dwc2 overlay installed?  Nothing will work if it isn't.
-LOGGER="systemd-cat -t gadget.sh"
 if lsmod | grep -q "dwc2"; then
-    $LOGGER -p info "DWC2 module loaded, setting up OTG gadget serial and ethernet"
+    systemd-cat -t gadget.sh -p info echo "DWC2 module loaded, setting up OTG gadget serial and ethernet"
 else
-    $LOGGER -p warning "DWC2 module missing.  Aborting OTG setup"
+    systemd-cat -t gadget.sh -p warning echo "DWC2 module missing.  Aborting OTG setup."
     exit 1
 fi
 
 
 sudo modprobe libcomposite
 cd /sys/kernel/config/usb_gadget
+# Was the script already run?
+if [ -d "MyGadget" ]; then
+    systemd-cat -t gadget.sh -p warning echo "MyGadget already exists.  Aborting OTG setup."
+    exit 1
+fi
+
 # Create our new gadget
 sudo mkdir MyGadget
 cd MyGadget

From 01b3a189ed83facac3fac11be6dd87ffb5eaa6eb Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Thu, 2 Jul 2026 10:34:26 +0000
Subject: [PATCH 03/16] enable/disable gettys as needed

---
 Scripts/gadget.sh | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Scripts/gadget.sh b/Scripts/gadget.sh
index 86514d4..fde27f2 100755
--- a/Scripts/gadget.sh
+++ b/Scripts/gadget.sh
@@ -8,20 +8,19 @@ if lsmod | grep -q "dwc2"; then
     systemd-cat -t gadget.sh -p info echo "DWC2 module loaded, setting up OTG gadget serial and ethernet"
 else
     systemd-cat -t gadget.sh -p warning echo "DWC2 module missing.  Aborting OTG setup."
+    systemctl disable serial-getty@ttyGS0.service
     exit 1
 fi
 
-
 sudo modprobe libcomposite
 cd /sys/kernel/config/usb_gadget
-# Was the script already run?
 if [ -d "MyGadget" ]; then
     systemd-cat -t gadget.sh -p warning echo "MyGadget already exists.  Aborting OTG setup."
     exit 1
 fi
 
 # Create our new gadget
-sudo mkdir MyGadget
+mkdir MyGadget
 cd MyGadget
 # Add some boilerplate data that the gadget needs
 echo 0x1d6b > idVendor # Linux Foundation’s USB VID. Replace with your own VID if required
@@ -46,6 +45,7 @@ echo "Config 1" > configs/c.1/strings/0x409/configuration
 ###  Remember to create the storage block device first
 ##  cd /root
 ### Example: Make a 256 MB file to act as "USB stick"
+##  Only create it once or it will delete the previous content
 ##  sudo dd if=/dev/zero of=drive.bin bs=1M count=256
 ### Create a VFAT file system on the backing store
 ##  sudo mkfs.vfat drive.bin
@@ -69,3 +69,6 @@ ln -s functions/ecm.usb0 configs/c.1/
 ## USB Device Controller update
 UDC=`ls /sys/class/udc`
 echo $UDC > UDC
+
+# Enable the gettys
+systemctl enable serial-getty@ttyGS0.service

From 9f51718235c8507ae101b99fdaebd75439c1221f Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Thu, 2 Jul 2026 10:39:13 +0000
Subject: [PATCH 04/16] test if running as root

---
 Scripts/gadget.sh | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Scripts/gadget.sh b/Scripts/gadget.sh
index fde27f2..490c1ef 100755
--- a/Scripts/gadget.sh
+++ b/Scripts/gadget.sh
@@ -3,6 +3,13 @@
 # "Using OTG mode on Raspberry Pi SBCs"
 # https://pip-assets.raspberrypi.com/categories/685-app-notes-guides-whitepapers/documents/RP-009276-WP/Using-OTG-mode-on-Raspberry-Pi-SBCs
 
+# This script only works if you are running it as root
+if [ $(id -u) -ne 0 ]; then
+    echo "Please run as root or use sudo"
+    exit 1
+fi
+
+
 # Is the dwc2 overlay installed?  Nothing will work if it isn't.
 if lsmod | grep -q "dwc2"; then
     systemd-cat -t gadget.sh -p info echo "DWC2 module loaded, setting up OTG gadget serial and ethernet"

From b43d1d67983705406f30be1706a5b476e6354bc2 Mon Sep 17 00:00:00 2001
From: Joseph Timothy Foley <foley@ru.is>
Date: Thu, 2 Jul 2026 16:13:20 +0000
Subject: [PATCH 05/16] added GPIO pinout document link

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 42174c0..1d4160a 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ Scripts and documentation for setting up a Raspberry Pi (Zero W 1 or 2) for use
 - [Starting on Raspberry Pi Zero](https://reykjavik.instructure.com/courses/6589/pages/starting-on-raspberry-pi-zero-w)
 
 ## References and Links
+- [Sparkfun GPIO pinout](https://cdn.sparkfun.com/assets/learn_tutorials/6/7/6/PiZero_1.pdf)
 - [Guide to creating ssh keys](https://pimylifeup.com/raspberry-pi-ssh-keys/)  Of note, this guide is a little dated as it suggests using RSA keys and many people are moving toward EDCSA keys.
 - [Raspberry Pi Connect](https://connect.raspberrypi.com)
     - [Setting up Raspberry Pi Connect](https://www.raspberrypi.com/documentation/services/connect.html)	

From aa83f5c957f3754b8bf9d8fad81edadcec628c3f Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Thu, 2 Jul 2026 16:56:44 +0000
Subject: [PATCH 06/16] got an LED to blink on GPIO18

---
 lgpio/blink.py    | 19 +++++++++++++++++++
 lgpio/pwm-test.py | 25 +++++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100755 lgpio/blink.py
 create mode 100755 lgpio/pwm-test.py

diff --git a/lgpio/blink.py b/lgpio/blink.py
new file mode 100755
index 0000000..7c6b782
--- /dev/null
+++ b/lgpio/blink.py
@@ -0,0 +1,19 @@
+#!/usr/bin/python
+# From https://raspberry.tips/en/raspberrypi-tutorials/raspberry-pi-gpio-python
+import lgpio
+import time
+
+# Open GPIO chip (0 = /dev/gpiochip0, on Pi 5 gpiochip4 also possible)
+h = lgpio.gpiochip_open(0)
+
+try:
+    lgpio.gpio_claim_output(h, 18)   # GPIO18 (pin 12) as output (MOTA1)
+
+    for _ in range(5):
+        lgpio.gpio_write(h, 18, 1)   # HIGH
+        time.sleep(0.5)
+        lgpio.gpio_write(h, 18, 0)   # LOW
+        time.sleep(0.5)
+    
+finally:
+    lgpio.gpiochip_close(h)          # Always close!
diff --git a/lgpio/pwm-test.py b/lgpio/pwm-test.py
new file mode 100755
index 0000000..e44f005
--- /dev/null
+++ b/lgpio/pwm-test.py
@@ -0,0 +1,25 @@
+#!/usr/bin/python
+# From https://raspberry.tips/en/raspberrypi-tutorials/raspberry-pi-gpio-python
+import lgpio
+import time
+
+# Open GPIO chip (0 = /dev/gpiochip0, on Pi 5 gpiochip4 also possible)
+h = lgpio.gpiochip_open(0)
+
+try:
+    lgpio.gpio_claim_output(h, 16)   # GPIO16 as output (MOTA2)
+    lgpio.gpio_write(h, 16, 0)   # LOW
+
+    # Hardware PWM on GPIO18 (pin 12) must be PWM-capable
+    # Frequency: 1000 Hz, duty cycle: 50%
+    lgpio.tx_pwm(h, 18, 1000, 50)
+    time.sleep(2)
+
+    # Reduce duty cycle to 20%
+    lgpio.tx_pwm(h, 18, 1000, 20)
+    time.sleep(2)
+
+    lgpio.tx_pwm(h, 18, 0, 0)   # Stop PWM
+    
+finally:
+    lgpio.gpiochip_close(h)          # Always close!

From 8dac7f365648f878b6dddbc51193cb824394ba1b Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Sat, 4 Jul 2026 15:57:49 +0000
Subject: [PATCH 07/16] PWM sweep test working

---
 lgpio/pwm-test.py | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/lgpio/pwm-test.py b/lgpio/pwm-test.py
index e44f005..2f05f1d 100755
--- a/lgpio/pwm-test.py
+++ b/lgpio/pwm-test.py
@@ -5,21 +5,21 @@ import time
 
 # Open GPIO chip (0 = /dev/gpiochip0, on Pi 5 gpiochip4 also possible)
 h = lgpio.gpiochip_open(0)
-
+# Hardware PWM on GPIO18 (pin 12) must be PWM-capable
+pwm_pin = 18
+pwm_freq = 1000
 try:
-    lgpio.gpio_claim_output(h, 16)   # GPIO16 as output (MOTA2)
-    lgpio.gpio_write(h, 16, 0)   # LOW
+    while True:
+        for pwm_level in range(0,100):
+            lgpio.tx_pwm(h, pwm_pin, pwm_freq, pwm_level)
+            pwm_level += 10
+            time.sleep(0.05)
+        for pwm_level in range(100,0,-1):
+            lgpio.tx_pwm(h, pwm_pin, pwm_freq, pwm_level)
+            pwm_level += 10
+            time.sleep(0.05)
 
-    # Hardware PWM on GPIO18 (pin 12) must be PWM-capable
-    # Frequency: 1000 Hz, duty cycle: 50%
-    lgpio.tx_pwm(h, 18, 1000, 50)
-    time.sleep(2)
-
-    # Reduce duty cycle to 20%
-    lgpio.tx_pwm(h, 18, 1000, 20)
-    time.sleep(2)
-
-    lgpio.tx_pwm(h, 18, 0, 0)   # Stop PWM
-    
+            
 finally:
+    lgpio.tx_pwm(h, pwm_pin, 0, 0)   # Stop PWM
     lgpio.gpiochip_close(h)          # Always close!

From 3358169ad86e4e496721f602f78a57cc2661b1cb Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Sat, 4 Jul 2026 18:41:02 +0000
Subject: [PATCH 08/16] Started documenting setting up PWM

---
 pwm.md | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 pwm.md

diff --git a/pwm.md b/pwm.md
new file mode 100644
index 0000000..243b593
--- /dev/null
+++ b/pwm.md
@@ -0,0 +1,53 @@
+# Getting the PWM working
+
+The Raspberry Pi zero (1 and 2) have 2 PWM peripherals, allowing you to pulse pins without the CPU doing any additional work.  This is particuarly useful for controlling motor speeds when connected to a motor driver/H-bridge chip.
+
+
+# References
+- [Raspberry Pi Official Overlays information (github)](https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README)
+    - Line 4235 starts the description of the "pwm" overlay configuration
+- [Adafruit 2-channel PWM instructions](https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio)
+
+# Discussion
+
+My raspberry pi zero W 2 wasn't working reliably with the PWM.
+
+The `gpio` command has been depricated and is now replaced by the `pinctrl` commend.  Running it did not list any PWM0 on any of the pins, which was concerning.
+
+[This forum post](https://forums.raspberrypi.com/viewtopic.php?t=388352) indicated the need for a `pwm-2chan` device tree overlay to get it to show up.  After adding `dtoverlay=pwm-2chan` to the `config.txt`:
+
+```
+$ pinctrl
+ 0: ip    -- | hi // ID_SDA/GPIO0 = input
+ 1: ip    -- | hi // ID_SCL/GPIO1 = input
+ 2: a0    -- | hi // GPIO2 = SDA1
+ 3: a0    -- | hi // GPIO3 = SCL1
+ 4: op -- -- | hi // GPIO4 = output
+ 5: ip    -- | hi // GPIO5 = input
+ 6: ip    -- | hi // GPIO6 = input
+ 7: op -- -- | hi // GPIO7 = output
+ 8: op -- -- | hi // GPIO8 = output
+ 9: a0    -- | lo // GPIO9 = SPI0_MISO
+10: a0    -- | lo // GPIO10 = SPI0_MOSI
+11: a0    -- | lo // GPIO11 = SPI0_SCLK
+12: ip    -- | lo // GPIO12 = input
+13: ip    -- | lo // GPIO13 = input
+14: ip    -- | lo // GPIO14 = input
+15: ip    -- | hi // GPIO15 = input
+16: ip    -- | lo // GPIO16 = input
+17: ip    -- | lo // GPIO17 = input
+18: a5    -- | lo // GPIO18 = PWM0
+19: a5    -- | lo // GPIO19 = PWM1
+```
+
+Which looks much better.
+There is a pwm chip `in /sys/class/pwm`
+
+After running the `lgpio/pwm-test.py`
+the pin is back to being listed as an input, so I'm confused.
+The PWM pin (under load) did the right values.  Without a load on the Analog Discovery 2, I just saw noise.
+
+I commented out `dtoverlay=pwm-2chan` and `lgpio/pwm-test.py` worked.
+The pwm chip is missing from `/sys/class/pwm` so I'm guess that's not needed.
+
+

From 18d01e181fe7218689a1237f41dd2e005dca7624 Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Sat, 4 Jul 2026 18:43:08 +0000
Subject: [PATCH 09/16] put proper Adafruit title

---
 pwm.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pwm.md b/pwm.md
index 243b593..55bce23 100644
--- a/pwm.md
+++ b/pwm.md
@@ -6,7 +6,10 @@ The Raspberry Pi zero (1 and 2) have 2 PWM peripherals, allowing you to pulse pi
 # References
 - [Raspberry Pi Official Overlays information (github)](https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README)
     - Line 4235 starts the description of the "pwm" overlay configuration
-- [Adafruit 2-channel PWM instructions](https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio)
+- [Adding Basic Audio Ouput to Raspberry Pi Zero](https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio)
+
+# Important Points
+1. The `gpio` program is no longer available.  It has been replaced with `pinctrl` which works a little differently.
 
 # Discussion
 

From 6009a5eff88c676d74632fa8b9351b9a78a01f0a Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Sat, 4 Jul 2026 18:45:10 +0000
Subject: [PATCH 10/16] procedure reminds people to put the SD card in

---
 imager.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/imager.md b/imager.md
index 7d02e84..a3f4827 100644
--- a/imager.md
+++ b/imager.md
@@ -44,6 +44,8 @@ We don't have many monitors and keyboards in V207 for students to use, so we wil
 ![imager-writeimage-verifying.png](Graphics/imager-writeimage-verifying.png)
 1. The process is complete!
 ![imager-complete.png](Graphics/imager-complete.png)
+1. Take the SD card and put it into your pi.
+1. When you first boot it, it can take 10 minutes to finish configuring itself.  Usually when the LED stops blinking for at least 30 seconds, it is done.
 
 ## Connecting using Raspberry Pi Connect
 1. Login to https://connect.raspberrypi.com if you haven't already

From f79b9985db52610662e7ed162f13c98f6a16594b Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Sat, 4 Jul 2026 19:34:38 +0000
Subject: [PATCH 11/16] The motor sweeps through the speeds (tested)

---
 lgpio/motor-test.py | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100755 lgpio/motor-test.py

diff --git a/lgpio/motor-test.py b/lgpio/motor-test.py
new file mode 100755
index 0000000..c7893fb
--- /dev/null
+++ b/lgpio/motor-test.py
@@ -0,0 +1,34 @@
+#!/usr/bin/python
+# This test assumes you are trying to control a motor through a DRV8833 motor
+# controller chip.  This general approach should work for other motors as well.
+import lgpio
+import time
+
+# pin assignments
+gpio_pwm = 18  #MOTA1
+gpio_reverse = 16 #MOTA2
+gpio_notsleep = 24 #MSLEEP
+# parameters
+pwm_freq = 1000
+
+
+h = lgpio.gpiochip_open(0)
+try:
+    lgpio.gpio_claim_output(h, gpio_reverse)
+    lgpio.gpio_claim_output(h, gpio_notsleep)
+    lgpio.gpio_write(h, gpio_reverse, 0)   # low on reverse pin to turn off h-bridge MOTA2
+    lgpio.gpio_write(h, gpio_notsleep, 1)   # high on /sleep to enable both h-bridges
+    
+    while True:
+        for pwm_level in range(0,100):
+            lgpio.tx_pwm(h, gpio_pwm, pwm_freq, pwm_level)
+            pwm_level += 10
+            time.sleep(0.05)
+        for pwm_level in range(100,0,-1):
+            lgpio.tx_pwm(h, gpio_pwm, pwm_freq, pwm_level)
+            pwm_level += 10
+            time.sleep(0.05)
+
+finally:
+    lgpio.gpio_write(h, gpio_notsleep, 1)   # high on /sleep to disable    
+    lgpio.gpiochip_close(h)          # Always close!

From a743e06b9b86c37c99adb421487c40687e8f102e Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Sat, 4 Jul 2026 19:36:30 +0000
Subject: [PATCH 12/16] reminder to create interface hat

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 1d4160a..aa383fe 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,7 @@ Scripts and documentation for setting up a Raspberry Pi (Zero W 1 or 2) for use
 
 ## TODO
 - Finding the Pi using `nmap` or `arp`
+- Create a interface HAT that makes it easy to attach to a digital analyzer (v207) and an Analog Discovery
 # Some Tricks
 
 Here is a page of tricks we have discovered that may involve advanced techniques.

From 582e2d4a16ba9a29916e2e427896d3ee01e069cd Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Sun, 5 Jul 2026 19:53:58 +0000
Subject: [PATCH 13/16] Blinka uses lgpio, so we get hardware pwm

---
 README.md | 1 +
 pwm.md    | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/README.md b/README.md
index aa383fe..2e38861 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@ Scripts and documentation for setting up a Raspberry Pi (Zero W 1 or 2) for use
 1. [Solder the GPIO header pins](solder-gpio.md)
 1. [Gadget Mode to setup a serial connection over USB](gadget.md)
 1. [Marcel's script on github to show the IP address on the OLED screen](https://github.com/mkyas/cpsy-display-ip)
+1. Install Blinka by following the guide [CircuitPython Libraries on Linux and Raspberry Pi](https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi)]
 
 ## RU student-only guides at ROB-IOT
 - [Starting on Raspberry Pi Zero](https://reykjavik.instructure.com/courses/6589/pages/starting-on-raspberry-pi-zero-w)
diff --git a/pwm.md b/pwm.md
index 55bce23..7b016bb 100644
--- a/pwm.md
+++ b/pwm.md
@@ -4,15 +4,20 @@ The Raspberry Pi zero (1 and 2) have 2 PWM peripherals, allowing you to pulse pi
 
 
 # References
+- [CircuitPython Libraries on Linux and Raspberry Pi](https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/installing-circuitpython-on-raspberry-pi)
 - [Raspberry Pi Official Overlays information (github)](https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README)
     - Line 4235 starts the description of the "pwm" overlay configuration
 - [Adding Basic Audio Ouput to Raspberry Pi Zero](https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio)
+- [CircuitPython pwmio documentation](https://docs.circuitpython.org/en/latest/shared-bindings/pwmio/index.html)
+
 
 # Important Points
 1. The `gpio` program is no longer available.  It has been replaced with `pinctrl` which works a little differently.
+1. The Blinka/CircuitPython interface uses `lgpio` to do hardware PWM on the pins.  This requires the `pwm-2chan` overlay to be setup correctly, which it's documented procedure does.  Details on relevant pins on line 4267 of the [overleays README](https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README)
 
 # Discussion
 
+
 My raspberry pi zero W 2 wasn't working reliably with the PWM.
 
 The `gpio` command has been depricated and is now replaced by the `pinctrl` commend.  Running it did not list any PWM0 on any of the pins, which was concerning.

From d86c7a224d36a6d3055edb12657de5e3ef18262e Mon Sep 17 00:00:00 2001
From: Joe Foley <foley@ru.is>
Date: Tue, 7 Jul 2026 00:09:35 +0000
Subject: [PATCH 14/16] Got bluetooth talking over a serial port

---
 bluetooth.md | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 bluetooth.md

diff --git a/bluetooth.md b/bluetooth.md
new file mode 100644
index 0000000..12392f1
--- /dev/null
+++ b/bluetooth.md
@@ -0,0 +1,79 @@
+# Bluetooth on the Raspberry Pi Zero W (1 or 2)
+The Zero W series has Bluetooth capability because of the Wifi chip on the board.
+**Warning:  This is a work in progress!!!**
+
+# Reference
+- "Exploring Raspberry Pi" by Derek Molloy pg 537-544
+- [Connecting to a Headless Raspberry Pi using Bluetooth](https://medium.com/@tomw3115/connect-to-a-headless-raspberry-pi-using-bluetooth-0e61c05e1b68)
+- https://github.com/sorah/bluetooth-getty
+- [Use dbus insteadd of sdptool](https://linuxvox.com/blog/bluez-adding-services-attributes-and-profiles-without-sdptool-command/)
+
+# Getting Bluetooth working
+1. Login to the pi via a USB-serial port or monitor-keyboard-mouse.  Configuring bluetooth can sometimes kick you off the wifi.
+1. Tell `rfkill` to unblock bluetooth.  Perhaps this is a security thing?
+```
+sudo rfkill unblock bluetooth
+```
+1. Restart the bluetooth service and check it's status
+```
+sudo systemctl restart bluetooth
+sudo systemctl status bluetooth
+```
+1. Figure out the address using `hcitool`
+```
+hcitool dev
+```
+1. If you have a laptop set to be discoverable, you can check if bluetooth is working
+```
+hcitool scan
+```
+1. You can then query that device for what services it offers
+```
+sdptool browse ADDRESS
+```
+1. Now we want to make the Pi discoverable to our phone, tablet, or laptop
+```
+sudo hciconfig hci0 piscan
+sudo hciconfig hci name RaspberryPi
+```
+1. A Serial Port Profile(SPP) is needed for our serial port
+```
+sudo sdptool add SP
+```
+1. For some reason, we have to put the bluetooth daemon in compatibility mode.  (True as of 2016-2026 --foley).  Find the line with `ExecStart` and put `--compat` at the end
+```
+sudo nano /lib/systemd/system/bluetooth.service
+```
+1. Test the SPP is setup
+
+```
+sudo sdptool browse local
+```
+1. Time to pair it with a device
+```
+sudo bluetoothctl
+discoverable on
+agent on
+pairable on 
+scan on
+```
+and once you have paired it
+```
+discoverable off
+exit
+```
+
+1. If this works, you can install the `bluetooth.services` and `rfcomm.service` files to automate some of this setup.
+```
+sudo cp bluetooth.service /etc/systemd/system/bluetooth.target.wants/.
+sudo cp rfcomm.service /etc/systemd/system/.
+sudo systemctl daemon-reload
+sudo systemctl enable rfcomm
+sudo reboot
+
+```
+
+
+
+# Discussion
+Apparently Bluez's `sdptool` is now depricated and they are telling people to use this new GATT via `busctl` or `dbus-send`. [linuxvox article on depricated sdptool](https://linuxvox.com/blog/bluez-adding-services-attributes-and-profiles-without-sdptool-command/)

From 464ed79f9522209d2b9295da86a06db2d72e10a6 Mon Sep 17 00:00:00 2001
From: "Joseph T. Foley" <foley@ru.is>
Date: Tue, 11 Aug 2026 23:26:41 +0000
Subject: [PATCH 15/16] otg service needs to run before serial-getty

---
 Scripts/serial-ether-gadget.service | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Scripts/serial-ether-gadget.service b/Scripts/serial-ether-gadget.service
index 05a912d..de4ff66 100644
--- a/Scripts/serial-ether-gadget.service
+++ b/Scripts/serial-ether-gadget.service
@@ -1,6 +1,7 @@
 [Unit]
 Description=Serial and Ethernet over OTG USB
-After=systemd-user-sessions.service
+#After=systemd-user-sessions.service
+Before=serial-getty@ttyGS0.service
 [Service]
 ExecStart=/root/rover-pi/Scripts/gadget.sh
 [Install]

From 075fd124cdc71e3c906b68a995057d32d9ee29f8 Mon Sep 17 00:00:00 2001
From: Joseph Timothy Foley <2+foley@noreply.localhost>
Date: Thu, 27 Aug 2026 13:38:17 +0000
Subject: [PATCH 16/16] forgot to go to root's home

---
 gadget.md | 239 +++++++++++++++++++++++++++---------------------------
 1 file changed, 120 insertions(+), 119 deletions(-)

diff --git a/gadget.md b/gadget.md
index 3c75f9d..3510cff 100644
--- a/gadget.md
+++ b/gadget.md
@@ -1,119 +1,120 @@
-# Gadget Mode to setup a serial connection over USB
-Prepare Raspberry Pi OS connection over a microUSB serial cable
-
-Based upon Adafruit guide: https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/serial-gadget:
-The author discovered the guide was out of date, consulted the [2025 Raspberry Pi whitepaper on OTG](https://pip-assets.raspberrypi.com/categories/685-app-notes-guides-whitepapers/documents/RP-009276-WP/Using-OTG-mode-on-Raspberry-Pi-SBCs), found additional errors, and was finally able to correct them thanks to this blog https://www.isticktoit.net/?p=1383
-
-## Important :
-- **Using the Gadget Mode will make the usb port unable to connect to a mouse or keyboard!!!** You will need to disable it make them work again.
-- You will want to disable the serial console on RX/TX in `raspi-config` if you are trying to use that serial port for communicating with other devices.
-
-
-## Procedure
-
-Make sure you have your USB cable plugged into the left port **USB** and not the right port marked **PWR**.
-1. Open a connection to the device via ssh or Raspberry Pi Connect
-1. Become root (the superuser)
-```
-sudo su
-```
-1. Enable the DWC version 2 USB peripheral device tree overlay by appending it to the end after the `[all]` category (which is at the end)
-```
-echo "dtoverlay=dwc2" >> /boot/firmware/config.txt
-```
-1. We add the required module `dwc2` for loading at startup
-```
-echo "dwc2" >> /etc/modules
-```
-1. Check that we can load the libcomposite module
-```
-modprobe libcomposite
-```
-1. Put a copy of this repository in root's home directory using git
-```
-apt install -y git
-git clone https://gitea.cs.ru.is/RU-V207/rover-pi.git
-```
-1. Go to Scripts and test if the `gadget.sh` runs without errors and hopefully a Serial port appers in Device Manager or equivalent
- ```
-cd rover-pi/Scripts/
-./gadget.sh
-```
-1. Install the systemd
-```
-cp serial-ether-gadget.service /lib/systemd/system/.
-```
-1. Enable the service
-```
-systemctl enable serial-ether-gadget.service
-```
-1. Enable the getty (which connects a login terminal to the serial port)
-```
-systemctl enable serial-getty@ttyGS0.service
-```
-1. Reboot and see if the serial port appears
-
-# Connecting to the serial terminal
-You will need a serial terminal program (which used to be very very common) in order to communicate over your serial port
-
-## Windows
-- Putty:  https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
-- MobaXterm: https://mobaxterm.mobatek.net/
-
-## Linux
-If using a Linux VM, you will need to pass the Pi USB connection there. 
-This is similar to the procedure for accessing an Arduino.
-1.  Start the Linux VM if you haven't already
-1. Menu: Devices > USB
-1. Look for "Silicon Labs CP210x USB to UART Bridge" and click on it.
-1. check if port /dev/ttyUSB0 is found. The Pi will most often be accessible over this port.
-    ```
-    ls -l /dev/ttyU*
-    ```
-1. The user must be in the dialout group to access it.  Use the Linux command: `uid` -to check if you are in the group. If not in the dialout group, use:
-    ```
-    sudo usermod -a -G dialout <username>
-	```
-1. You will use the GNU `screen` application in Linux to access the Pi.  You can install it with:
-    ```
-    sudo apt install screen
-	```
-1. You should now gain access to the Pi with:
-	```
-  ` sudo screen /dev/ttyUSB0 115200
-    ```
-1. Press enter and you will be prompted to log in to the Pi with default credentials. User: pi - PW: raspberry
-
-# Disabling the OTG mode to use a keyboard and mouse again
-
-**WARNING: Untested**
-1. Comment out the dwg2 line in `/boot/firmware/config.txt` using a `#` in front of the line
-   ```
-   [all]
-   #dtoverlay=dwg2
-   ```
-1. Comment out the dwg2 line in `/etc/modules` using a `#` in front of the line
-   ```
-   #dwg2
-   ```
-1. Disable the gadget service
-    ```
-	systemctl disable serial-ether-gadget.service
-	```
-1. Disable the getty
-    ```
-	systemctl disable serial-getty@ttyGS0.service
-	```
-
-# Connecting over the USB ethernet to ssh into your Pi
-
-I have not tested this procedure because the serial console and normal network connection is sufficient for me --foley
-
-https://www.raspberrypi.com/news/usb-gadget-mode-in-raspberry-pi-os-ssh-over-usb/
-
-
-# Untested
- Here are items that bear investigating but haven't been tested yet
- 
- - [Modify Imager manifest to install otg](https://github.com/raspberrypi/rpi-imager/tree/main/doc/local_json)
- 
+# Gadget Mode to setup a serial connection over USB
+Prepare Raspberry Pi OS connection over a microUSB serial cable
+
+Based upon Adafruit guide: https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/serial-gadget:
+The author discovered the guide was out of date, consulted the [2025 Raspberry Pi whitepaper on OTG](https://pip-assets.raspberrypi.com/categories/685-app-notes-guides-whitepapers/documents/RP-009276-WP/Using-OTG-mode-on-Raspberry-Pi-SBCs), found additional errors, and was finally able to correct them thanks to this blog https://www.isticktoit.net/?p=1383
+
+## Important :
+- **Using the Gadget Mode will make the usb port unable to connect to a mouse or keyboard!!!** You will need to disable it make them work again.
+- You will want to disable the serial console on RX/TX in `raspi-config` if you are trying to use that serial port for communicating with other devices.
+
+
+## Procedure
+
+Make sure you have your USB cable plugged into the left port **USB** and not the right port marked **PWR**.
+1. Open a connection to the device via ssh or Raspberry Pi Connect
+1. Become root (the superuser)
+```
+sudo su
+```
+1. Enable the DWC version 2 USB peripheral device tree overlay by appending it to the end after the `[all]` category (which is at the end)
+```
+echo "dtoverlay=dwc2" >> /boot/firmware/config.txt
+```
+1. We add the required module `dwc2` for loading at startup
+```
+echo "dwc2" >> /etc/modules
+```
+1. Check that we can load the libcomposite module
+```
+modprobe libcomposite
+```
+1. Put a copy of this repository in root's home directory using git
+```
+cd /root
+apt install -y git
+git clone https://gitea.cs.ru.is/RU-V207/rover-pi.git
+```
+1. Go to Scripts and test if the `gadget.sh` runs without errors and hopefully a Serial port appers in Device Manager or equivalent
+ ```
+cd rover-pi/Scripts/
+./gadget.sh
+```
+1. Install the systemd
+```
+cp serial-ether-gadget.service /lib/systemd/system/.
+```
+1. Enable the service
+```
+systemctl enable serial-ether-gadget.service
+```
+1. Enable the getty (which connects a login terminal to the serial port)
+```
+systemctl enable serial-getty@ttyGS0.service
+```
+1. Reboot and see if the serial port appears
+
+# Connecting to the serial terminal
+You will need a serial terminal program (which used to be very very common) in order to communicate over your serial port
+
+## Windows
+- Putty:  https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
+- MobaXterm: https://mobaxterm.mobatek.net/
+
+## Linux
+If using a Linux VM, you will need to pass the Pi USB connection there. 
+This is similar to the procedure for accessing an Arduino.
+1.  Start the Linux VM if you haven't already
+1. Menu: Devices > USB
+1. Look for "Silicon Labs CP210x USB to UART Bridge" and click on it.
+1. check if port /dev/ttyUSB0 is found. The Pi will most often be accessible over this port.
+    ```
+    ls -l /dev/ttyU*
+    ```
+1. The user must be in the dialout group to access it.  Use the Linux command: `uid` -to check if you are in the group. If not in the dialout group, use:
+    ```
+    sudo usermod -a -G dialout <username>
+	```
+1. You will use the GNU `screen` application in Linux to access the Pi.  You can install it with:
+    ```
+    sudo apt install screen
+	```
+1. You should now gain access to the Pi with:
+	```
+  ` sudo screen /dev/ttyUSB0 115200
+    ```
+1. Press enter and you will be prompted to log in to the Pi with default credentials. User: pi - PW: raspberry
+
+# Disabling the OTG mode to use a keyboard and mouse again
+
+**WARNING: Untested**
+1. Comment out the dwg2 line in `/boot/firmware/config.txt` using a `#` in front of the line
+   ```
+   [all]
+   #dtoverlay=dwg2
+   ```
+1. Comment out the dwg2 line in `/etc/modules` using a `#` in front of the line
+   ```
+   #dwg2
+   ```
+1. Disable the gadget service
+    ```
+	systemctl disable serial-ether-gadget.service
+	```
+1. Disable the getty
+    ```
+	systemctl disable serial-getty@ttyGS0.service
+	```
+
+# Connecting over the USB ethernet to ssh into your Pi
+
+I have not tested this procedure because the serial console and normal network connection is sufficient for me --foley
+
+https://www.raspberrypi.com/news/usb-gadget-mode-in-raspberry-pi-os-ssh-over-usb/
+
+
+# Untested
+ Here are items that bear investigating but haven't been tested yet
+ 
+ - [Modify Imager manifest to install otg](https://github.com/raspberrypi/rpi-imager/tree/main/doc/local_json)
+