Cheap AVR debugger works well.... and then it doesn't :-(

Go To Last Post
18 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Does anyone have any experience with this debugger?

https://sites.google.com/site/wayneholder/debugwire3

 

I have been experimenting with it and is a great little project.

Except after a while it is not....

 

I have two tinies that are stuck in dwEnable mode. They run the code loaded into them perfectly well. The various dw commands work.

However when I disable dw.... the ISP interface does not work.

 

I have checked MOSI, MISO, SCK and nReset and all waveforms look OK. Except that the MISO waveform always mirrors the the MOSI waveform. i.e. there s no response form the target uc.

 

I have run test code on the 328 master and all digital pins can generate high/low conditions and detect same. So the master end seems OK.

 

It feels like I have somehow cooked some part of the IO pins on the Tiny. Not sure how I would have done that. My target code does not use those pins so the idea that my code was driving high against a low master doesn't seem to be the issue.

 

Any thoughts on non responding ISP interfaces would be appreciated.

 

Thanks in advance

Greg

regards
Greg

Last Edited: Thu. May 12, 2022 - 01:07 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

No,  I have not used or even heard of the "On the Cheap Debugger".

 

By the time that you have bought the components and pcb it probably adds up to the same cost as an XMINI-328 board.

Or just buying a Pro-Micro / Leonardo clone and installing mEDBG firmware.

 

But if you are interested in AVR as a hobby,  you might just as well future-proof yourself with a SNAP or PicKit4.

Both of which will work with PDI, UPDI, JTAG, SWD, debugWIRE, ISP, TPI, ...

 

David.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

All of this ^^ is absolutely true. Thanks. 
 

still interested if anyone has any ideas on what might have happened to the isp interface. 

regards
Greg

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Engineering axiom: Good / Cheap / Fast,   Pick any two, note, cheap fast is seldom the right choice....

 

 

 

 

FF = PI > S.E.T

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

gregd99 wrote:
Does anyone have any experience with this debugger?
No though am skeptical of the 10 micro-farad capacitor (significant di/dt)

Arduino as ISP and Arduino Bootloaders | Arduino Documentation

[mid-page]

...

Boards like Leonardo, Esplora and Micro, with the USB directly managed by the microcontroller, don't need the capacitor.

compared with

Reset Line | AVRISP mkII

Any decoupling capacitor should not be larger than 10μF. 

which has some impedance (current limiting)

Short Circuit Protection | AVRISP mkII

 

"Dare to be naïve." - Buckminster Fuller

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

ki0bk wrote:
cheap fast is seldom the right choice....
debugWIRE is slower than UPDI (AVRxt); would recommend AVRxt tinyAVR though tiny85 (AVRe) doesn't have a follow-on (very low pin count and 8 KB program space)

 

debugWIRE via USB UART | AVR Freaks

 

"Dare to be naïve." - Buckminster Fuller

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

If you are anywhere near Baulkham Hills I have an Atmel ICE (as well as others) to try and restore the chips.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks for the generous offer. I am on the Northern beaches.

 

The issue is no so much the cooked chips.... but why it happened. I had been thinking a sw issue causing an electrical failure... but haven't found it yet.

 

I am thinking more about Snap.

Any thoughts or comments on this device with AS7 and attiny85?

regards
Greg

Last Edited: Fri. May 13, 2022 - 05:49 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

gregd99 wrote:
but why it happened.

Does this cheap debugger drive the DW line as push-pull?  And can that damage the /RESET in some way...? (not really an expert)

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

gregd99 wrote:
I am thinking more about Snap.

Any thoughts or comments on this device with AS7 and attiny85?

Shouldn't be an issue; MPLAB Snap firmware is only in an MPLAB X (IDE and IPE) tool pack and, IIRC, only MPLAB X can update Microchip tool firmware.

Microchip Technology tools are in PIC mode from the factory (iow not EDBG)

 

https://packs.download.microchip.com/#collapse-Microchip-Snap-TP-pdsc

MPLAB Snap | Page 2 | AVR Freaks

SNAP with Atmel Studio | AVR Freaks

Getting SNAP to work with AVR on AS7.0.2542 | AVR Freaks

 

"Dare to be naïve." - Buckminster Fuller

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

gchapman wrote:

only MPLAB X can update Microchip tool firmware.

hopefully this can change one day... ?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

mraardvark wrote:
Does this cheap debugger drive the DW line as push-pull?
Another inexpensive debugWIRE PHY is a USB UART with a signal diode to prevent current injection.

mraardvark wrote:
And can that damage the /RESET in some way...?
Shouldn't with current limiting and a voltage clamp (injection current)

 


Wiring the FT232R/CH340 adapter | GitHub - dcwbrown/dwire-debug: Simple stand-alone debugger for AVR DebugWIRE chips connected directly to an FT232R/CH340/DigiSpark/LittleWire on Linux or Windows.

[last two paragraphs]

For an out of circuit connection, set the adapter to whichever voltage matches the voltage range supported by the AVR device. For an ATtiny45, either voltage is fine.

 

For an in-circuit connection, the Vcc power line is not connected, and setting the adapter to 5v should work for any circuit: The diode protects the circuit from any damage - it can only pull the DebugWIRE pin low - it cannot feed overvoltage to the AVR.

Planet Analog - SIGNAL CHAIN BASICS #66: How to interface a 5V transceiver to a 3V controller -

 

Connection of RESET Pin on AVR Devices | AVR® Microcontroller Hardware Design Considerations (AVR042)

External RESET Switch | AVR® Microcontroller Hardware Design Considerations

 

"Dare to be naïve." - Buckminster Fuller

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Python is enough; went looking though came up short.

Microchip PIC&AVR Tools · GitHub

 

If you mean Microchip Studio then I hope so.

Transparency : Am an optimist for Microchip Studio 8 in the form of a Visual Studio extension otherwise a community effort.

 


Visual Studio Embedded | AVR Freaks

 

"Dare to be naïve." - Buckminster Fuller

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

mraardvark wrote:

gchapman wrote:

 

only MPLAB X can update Microchip tool firmware.

 

 

hopefully this can change one day... ?

look at some files at microchip folder.It contain firmware.

www.tokopedia.com/madagang .Buy and Donated cheap electronics and manuscripts.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Maybe you've locked the fuse bits. Try using a fuse-bit unlocker if you have or can borrow any. 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

gregd99 wrote:
when I disable dw.... the ISP interface does not work

 

Just an option: do cycle the power to device

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

gregd99 wrote:

However when I disable dw.... the ISP interface does not work.

 

From a related thread gregd99 shows a reluctance to follow the AS7.0 prompts.

 

The simple rules are:

1.  dW Enable requires power-cycling when prompted.   i.e. after the ISP sequence.

2.  dW Disabling must not lose power during any part of the dW+ISP sequence.

 

David.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

david.prentice wrote:

The simple rules are:

1.  dW Enable requires power-cycling when prompted.   i.e. after the ISP sequence.

2.  dW Disabling must not lose power during any part of the dW+ISP sequence.

 

David.

yes

www.tokopedia.com/madagang .Buy and Donated cheap electronics and manuscripts.