Debugging

13-03-2023

Fab Academy 2023

by: Henk & Nicolas

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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

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Attitude & General principles

Slides by Fran & Duaa

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ERROR

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Don't jump to conclusions

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

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Write

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

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Read

Don't forget to undrestand what you just read!

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Don't Panic8 / 56

Narrowing down the problem

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...

Image by Jonathan Blok - Waag

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It's not working

Concentrate only on the relevant parts. Isolate the problem.

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The microcontroller is not receiving voltage / the wrong voltage

Big chance the problem is located here.

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Can't program the microcontroller

Big chance the problem is located here.

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Programmed, unable to program other microcontrollers

Big chance the problem is located here.

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

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

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Voltage

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

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Power supplyNothing : 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
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How to check current, resistor, capacitor, ...

Learn more about you mulimeter capabilites!
Circuit modify compononents behaviours! (resistance, cap,... in circuit)
Current : serie
Resistor : parallel
capacitor : parallel (+ polarity)

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MultiMeter

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Voltage Drop

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Logical analyzerVariable digital signals
Communications [UART, I²C, SPI, 1-Wire, ...]
PWM
Clock
...
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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, Pulseview with Cypress CY7C68013A, ...

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Logic Analayzer

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Logic Analayzer

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LA104 + DS213

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

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Pinecile / TS80P

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DPS3005 Bench Power Supply

DPS3005/5005

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DPS3005 Bench Power Supply

PyGUI

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Flashing your board

And what can go wrong

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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

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EDBG for flashing ARM (2)

List programmers

edbg -b -l

Erase first (!) and load program

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

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UPDI for Flashing AVR (1)

All you need is a serial adapter
RX and TX connected together with a 4.7k resistor or diode
(any res. between 1.5k and 10k will work)
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)

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UPDI for Flashing AVR (2)

pymcuprog.py

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 UPDI with 4.7k resistor or diode SLOW (57600 bauds)" 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?
- have you changed UPDI pin function? (will require HV programmer!)

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In-circuit / On-Chip debugging

Advanced debugging

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Atmel ICE

Atmel-ICE
Allows you to pause execution (breakpoints / run-to-cursor)
Watch variables and registers
Tightly integrated within Atmel Studio

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OpenOCD+GDB for debugging SAMD

Open source alternative to Atmel Studio debugging
Dedicated recitation about samd + openOCD debugging : https://www.youtube.com/watch?v=P5Jun-jLRMY
Install on windows: https://gnutoolchains.com/arm-eabi/openocd/
Install on linux:

apt get install openocd

Create openocd.cfg:

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:

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

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Debugging SAM-Based Arduino® Boards:

https://docs.arduino.cc/tutorials/mkr-wifi-1010/atmel-ice

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esptool

Espressif chips ROM Bootloader Utility

- Port problem

- Wrong chip

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Serial (or any) "Hello world!"

Sending internal info through communication line

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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:

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

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USB

Check your USB device can be found by the OS

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USB

$ 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

$ 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
Bus 001 Device 029: ID 6666:6666 Prototype product Vendor ID

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)

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USB

$ dmesg -w

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Radio Communications

How to see what you can't even touch?

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Radio communications

Frequency ranges (~kHz to ~GHz)
Use receiver modules
DVB-T receiver as radio tool : GNU Radio (live), SDR environment

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Radio communications

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Happy Debugging

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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

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Debugging

Attitude & General principles

ERROR

Don't jump to conclusions

Write

Read

Don't Panic

Narrowing down the problem

It's not working

The microcontroller is not receiving voltage / the wrong voltage

Can't program the microcontroller

Programmed, unable to program other microcontrollers

Multimeter

Continuity

Voltage

Power supply

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

MultiMeter

Voltage Drop

Logical analyzer

Logical analyzers

Logic Analayzer

Logic Analayzer

LA104 + DS213

Oscilloscope

Oscilloscope (main functions)

Pinecile / TS80P

DPS3005 Bench Power Supply

DPS3005 Bench Power Supply

Flashing your board

EDBG for flashing ARM (1)

EDBG for flashing ARM (2)

UPDI for Flashing AVR (1)

UPDI for Flashing AVR (2)

In-circuit / On-Chip debugging

Atmel ICE

OpenOCD+GDB for debugging SAMD

esptool

Serial (or any) "Hello world!"

Serial (or any) "Hello world!"

USB

USB

USB

Radio Communications

Radio communications

Radio communications

Happy Debugging

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