Debugging

# Debugging
![](./img/debugging.jpg)

28-02-2022

Fab Academy 2022

???

Press 'p' to enter presentation mode. Or even better:

1. press 'c' to clone the page
2. press 'p' to enter presentation mode
3. used cloned view for beam, share screen in zoom.

---

1-Attitude
2-General principles
3-Multimeter
4-Logical analyzers
5-Oscilloscope
6-How to debug almost anything kit
7-Flashing your board
8- Microcontroller debugging
9-Serial (or any) "Hello world!"
10-USB and computer detection
11 -Radio Communications

---
class: center, middle, chapter

# Attitude & General principles

![](./img/attitude.jpg)

---
class: middle, center

## ERROR

---

<p>
.image_right[
<img src="img/jump.jpg" height="500px">
]

## Don't jump to conclusions

<p>

- Approach the problem objectively
- Everyone (everything) is a suspect!

---

<p>
.image_right[
<img src="img/colombo1.jpg" height="600px">
]

## Write

<p>

- what is happening
- what is the environment
- what are you doing
- what are the results

---

## Read

Don't forget to undrestand what you just read!
---

## Narrowing down the problem
<P>
.image_right[
<img src="img/visual.jpg" height="400px">
]

<p>

- Reproduce the problem
- Always first do visual check

- traces
	- solder
	- components

- Keep in mind that the problem might not be visible without a microscope

Everything looks good but...

---

## It's not working

![](./img/D11Cserial.jpg)

Concentrate only on the relevant parts. Isolate the problem.

---

## The microcontroller is not receiving voltage / the wrong voltage

![](./img/D11Cserial-1.jpg)

Big chance the problem is located here.

---

## Can't program the microcontroller

![](./img/D11Cserial-2.jpg)

Big chance the problem is located here.

---

## Programmed, unable to program other microcontrollers

![](./img/D11Cserial-3.jpg)

Big chance the problem is located here.

---

# Multimeter

- "Continuous" phenomenons
- Continuity check (+diodes orientation) : symbol
- Voltage/Power check : parallel measurement
- Resistance / current / ...

---

## Continuity

- Test power supply to power pins continuity
- Check fuses, diodes orientations, ...
- Check short-circuits
- Check traces

![](img/continuity.jpg)

---

## Voltage

- Parallel measurement => check your cables!
- ! absolute maximum ratings (may burn your component)
- Power supply impedence / max power, badly selected
- GND/VCC loop

---

## Power supply

- Nothing : open circuit, short circuit, line break, blown fuse, ...
- Voltage too low : power supply impedence, badly selected, ...
- Voltage too high : above max. ratings, dead zener/reg., ...
- GND/VCC loop

---

## How to check current, resistor, capacitor, ...

- Learn more about you mulimeter capabilites!
- Current : serie
- Resistor : parallel
- capacitor : parallel (+ polarity)

---

## MultiMeter

---

## Voltage Drop

---

# Logical analyzer

- Variable **digital** signals
- Communications [UART, I²C, SPI, 1-Wire, ...]
- PWM
- Clock
- ...

---

## Logical analyzers

- High sampling rates (> 100MHz - 500 MHz)
- Only "logical levels" (0 : <0.6V - 1 : > 1.2V => usually not CMOS logic!)
- Multiple channels (8-16...)
- "Unexpensive" (compared to oscilloscopes)
- Allows you to read complex protocols easily

[Saleae](https://www.saleae.com/), [Pulseview](https://sigrok.org/wiki/PulseView) with Cypress CY7C68013A, ...

---

# Logic Analayzer

---

# Logic Analayzer

- ["logic analyzer 8 channel"](https://www.amazon.com/KeeYees-Analyzer-Device-Channel-Arduino/dp/B07K6HXDH1)
- ["logic analyzer 16 channel"](https://nl.aliexpress.com/item/4000386048107.html)
- ["Digikey 461-1010-ND: MICRO-HOOK RED 0.025" SQ PINS "](https://www.digikey.com/en/products/detail/e-z-hook/XKMRED/528231)
- ["Digikey 461-1010-ND: MICRO-HOOK BLACK 0.025" SQ PINS "](https://www.digikey.com/en/products/detail/e-z-hook/XKMBLK/528230?s)

---

# LA104 + DS213

<p>
.image_right[
<img src="./img/24.jpg" height="400px">
]

- [LA104](http://www.miniware.com.cn/product/signal-analyzer/)
- [DS213](http://www.miniware.com.cn/product/ds213-mini-oscilloscope/)

---

# Oscilloscope

- "Variable / random" phenomena
- Variable signals (analog, communications, blink, sound, ...)

---
<div class="my-footer"><span>
<a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/80x15.png" /></a></a>
FabAcademy 2022 - recitation on debugging  </span></div>

## Oscilloscope (main functions)

- "Real" voltage levels, high sampling rate (> 10MHz - 1GHz)
- Dynamic view
- Triggers/Time/Level
- Lots of analysis capabilities inside (play with menus : capture/ analyse / freq-time / intervals / Peak-peak / frequency / ...)
- Few channels (~1-4)
- Expensive tool. Poor human alternative : sound card mic/line input [< 44.1kS/sec]

---

"Random" behaviours :
- Check proper signals
- Check proper power (stable enough?)
- DC decoupling capacitor? (same idea as toilet flush ;-) )

---

---

<div class="my-footer"><span>
<a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/80x15.png" /></a></a>
FabAcademy 2022 - recitation on debugging  </span></div>
<center> <iframe width="672" height="378" src="https://www.youtube.com/embed/HJwMpVrwPUQ" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> </center>

---

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FabAcademy 2022 - recitation on debugging  </span></div>
<center> <iframe width="672" height="378" src="https://www.youtube.com/embed/6btUw8nLmuU" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> </center>

---

<div class="my-footer"><span>
<a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/80x15.png" /></a></a>
FabAcademy 2022 - recitation on debugging  </span></div>
<center> <iframe width="672" height="378" src="https://www.youtube.com/embed/DHvR1r6aXpw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> </center>

---
<div class="my-footer"><span>
<a rel="license" href="http://creativecommons.org/licenses/by-nc/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc/4.0/80x15.png" /></a></a>
FabAcademy 2022 - recitation on debugging  </span></div>

## Pinecile

- [Pinecil](https://pine64.com/product/pinecil-smart-mini-portable-soldering-iron/)

## DPS3005 Bench Power Supply

- [DPS3005/5005](https://nl.aliexpress.com/item/4001237790968.html)

## DPS3005 Bench Power Supply

- [PyGUI](https://github.com/lambcutlet/DPS5005_pyGUI)

---

# Flashing your board
And what can go wrong

## EDBG for flashing ARM (1)

- Connect a CMSIS-DAP SWD adapter
- 10-pin 1.27mm connectors are convenient, but triple check the orientation
- If VCC pin is unused, power your target device separately
- Make sure the programmer is on 3.3V if programming SAMD

## EDBG for flashing ARM (2)

- List programmers

```c
edbg -b -l
```

- Erase first (!) and load program

```c
edbg -ebpv -t <processor> -f <program.bin>
```

- flags:
	- -b: verbose (optional)
	- -e: erase
	- -p: program
	- -v: verify (optional)
	- -t: target type (e.g. samd11)

- Common problems
	- Programmer not listed: check USB
	- Invalid response: check JTAG connection

## UPDI for Flashing AVR (1)

- All you need is a serial adapter
- RX and TX connected together with a 4.7k resistor
- VCC is optional but ensures both chips talk at the same logic level
- Programming is initiated with a break (LOW level for a long duration)

## UPDI for Flashing AVR (2)

- pymcuprog.py

```c
pymcuprog -d <processor> -t uart -u <port> -v info erase
pymcuprog -d <processor> -t uart -u <port> -v info write -f <program.hex>
```

- Arduino IDE
	- install megaTinyCore (ATtiny 1-series) or DxCore (AVR DA/DB)
	- use "serial port and 4.7k (pyupdi style) SLOW" programmer
	- select correct serial port and click upload

- Common problems
	- wrong serial settings: adapter needs 2 Stop bits and Even parity
	- "incorrect echo": are RX and TX connected together?
	- "UPDI initialisation failed": have you tried turning it off and on again?

---

# In-circuit / On-Chip debugging

Advanced debugging

## Atmel ICE

- [Atmel-ICE](https://www.microchip.com/DevelopmentTools/ProductDetails/ATATMEL-ICE)
- Allows you to pause execution (breakpoints / run-to-cursor)
- Watch variables and registers
- Tightly integrated within **Atmel Studio**

## OpenOCD+GDB for debugging SAMD

- Open source alternative to Atmel Studio debugging
- Install on windows: https://gnutoolchains.com/arm-eabi/openocd/
- Install on linux:

```bash
apt get install openocd
```
- Create `openocd.cfg`:

```c
source [find interface/cmsis-dap.cfg]

set CHIPNAME at91samd11c14

source [find target/at91samdXX.cfg]
```

- Connect SWD programmer and launch: `openocd`
- Connect to opencd with gdb:

```bash
arm-none-eabi-gdb -iex "target extended-remote localhost:3333"
```

---

# Serial (or any) "Hello world!"

Sending internal info through communication line

---

## Serial (or any) "Hello world!"

- Show any external signal on code execution (eg : LED blinking)
- Send register value or "hello world" message through communication lines (eg : serial/UART)
- Very simple to implement but requires functional microcontroller
- Allows you to follow execution steps

Example:
```c
#define DEBUG_MODE 1
...
#if DEBUG_MODE
  Serial.print("DEBUG -- MyVal value = ");
  Serial.println(MyVal, DEC);
#endif
```

---

# USB

Check your USB device can be found by the OS

---
<div class="my-footer"><span>
<a rel="license" href="http://creativecommons.org/licenses/by/4.0/"><img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by/4.0/80x15.png" /></a></a>
Fab Academy 2020 - recitation on debugging  </span></div>

## USB

.small[
```terminal
$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 046d:c05a Logitech, Inc. M90/M100 Optical Mouse
Bus 001 Device 004: ID 413c:2011 Dell Computer Corp. Multimedia Pro Keyboard
```
]

If nothing :
- Check you load **proper bootloader**!
- Check lines, voltages ("5V" power BUT 3.3V communication D-/D+), zener orientations, ...

If declared but doesn't work :
- Check USB devices permissions
- Check firmware (inject a tried-and-tested)

## USB

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 <source src="./img/dmesg.mp4" type="video/mp4">
Your browser does not support the video tag.
</video>

]

---

# Radio Communications

How to see what you can't even touch?

## Radio communications

- Frequency ranges (~kHz to ~GHz)
- Use receiver modules
- DVB-T receiver as radio tool : [GNU Radio (live), SDR environment](https://wiki.gnuradio.org/index.php/GNU_Radio_Live_SDR_Environment)

## Radio communications

<video width="720" height="480" controls>
 <source src="./img/sdr.mp4" type="video/mp4">
Your browser does not support the video tag.
</video>

]

## Happy Debugging