Provide user config value "default_baudrate" (acc. discussion #1589)

[Ho-Ro]

No description provided.

[stefanrueger]

Thanks for the PR!

What happens if both a programmer default baudrate is set and the newly introduced one? And, more importantly, what should happen , ie, which one should prevail? In any case -b should win over both other methods. I guess the programmer-specific default baud rate should win over the newly introduced global one, but I have not thought about this deeply. This precedence ought to be documented better.

[Ho-Ro]

What happens if both a programmer default baudrate is set and the newly introduced one?

If both values are defined in ~/.avrduderc, then the global default_baudrate has priority over baudrate in a programmer entry. This seems confusing at first glance, but it is usually the case that a baudrate entry in the global config file is to be corrected.
So -b xxx has priority over default_baudrate, which in turn has priority over baudrate in the programmer entries.

[stefanrueger]

Thinking a bit more about that, if you have a programmer with a fixed hard-coded baudrate and a different favourite baudrate otherwise, would it not make more sense to only use the global default_baudrate if neither a command line -b is specified (highest prio) nor a programmer-specific default baudrate was specified (second prio)? Otherwise you'd have to explicitly use -b for your programmers with hard-coded baudrates once you use a global default_baudrate.

[Ho-Ro]

Ok, changed the hierarchy:
baudrate (set by -b) has priority over pgm->baudrate which has priority over default_baudrate.

Please review.

EDIT:
I've thought about the verbosing of the baudrate values again and will suggest a better solution later - some programmers don't need a baudrate and it makes no sense to display it even if it's provided by -b, e.g.:

$ avrdude -pm328p -v -c atmelice_isp -b12345

avrdude: Version 7.2
         Copyright the AVRDUDE authors;
         see https://github.com/avrdudes/avrdude/blob/main/AUTHORS

         System wide configuration file is /home/horo/projects/AVR/avrdude-7.2/build_linux/src/avrdude.conf
         User configuration file is /home/horo/.avrduderc

         Using Port                    : usb
         Using Programmer              : atmelice_isp
         Overriding Baud Rate          : 12345

Maybe the best idea would be to drop the PR, no need for the parameter default_baudrate because you can always define your own programmer with a different baudrate in ~/.avrduderc, I do that for my nanoSTK with 500kbps for example.

Two steps forward and one step back - I can provide a new PR that displays Overriding Baud Rate only if it overrides a defined baud rate, i.e.

baudrate != 0 && pgm->baudrate !=0 && baudrate != pgm->baudrate

What's your opinion?

[stefanrueger]

you can always define your own programmer

I like this PR. It is an awful lot of work to add 140 private programmers just to express a default baud rate.

The only thing missing is the documentation that default_baudrate is only consulted in absence of programmer-specific default and in absence of -b.

And yes, displaying Overriding Baud Rate is kinda neater when it's actually overridden (though I can live with overclaiming that the baud rate was set to a different value when it wasn't).

[Ho-Ro]

Ok, it's complete for my understanding - please have a look.
I checked:

default_baudrate	pgm->baudrate	-b	display	result
none	none	none		0
X	none	none	Default baud rate	X
none	Y	none	Programmer baud rate	Y
X	Y	none	Programmer baud rate	Y
none	none	Z	Setting baud rate	Z
X	none	Z	Overriding baud rate	Z
X	none	X	Default baud rate	X
none	Y	Z	Overriding baud rate	Z
none	Y	Y	Programmer baud rate	Y
X	Y	Z	Overriding baud rate	Z
X	Y	Y	Programmer baud rate	Y
X	Y	X	Overriding baud rate	X

X, Y, Z are three different baud rate values

avrdude.texi and avrdude.1 are updated accordingly

[stefanrueger]

Table looks great. Would be wonderful if there was some independent testing whether the implementation follows suit.

Thanks @Ho-Ro

[mcuee]

I should be able to give this PR some simple tests over the weekend when I have access to my HW.

[mcuee]

Hmm, I need to use another programmer to test this feature. I will carry out the test tomorrow using other programmers.
-c stk500v2 seems to support only baud rate of 115200.

PS> ./avrdude_pr1590 -C ./avrdude_pr1590.conf -c stk500v2 -P COM41 -p m328pb -b  115200
avrdude_pr1590: AVR device initialized and ready to accept instructions
avrdude_pr1590: device signature = 0x1e9516 (probably m328pb)

avrdude_pr1590 done.  Thank you.

PS> ./avrdude_pr1590 -C ./avrdude_pr1590.conf -c stk500v2 -P COM41 -p m328pb -b  230400
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout communicating with programmer
avrdude_pr1590 error: unable to open port COM41 for programmer stk500v2
A possible candidate serial port is:
  -P COM41 or -P ch340
Note that above port might not be connected to a target board or an AVR programmer.
Also note there may be other direct serial ports not listed above.

avrdude_pr1590 done.  Thank you.

PS> ./avrdude_pr1590 -C ./avrdude_pr1590.conf -c stk500v2 -P COM41 -p m328pb -b 57600
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout
avrdude_pr1590 error: timeout communicating with programmer
avrdude_pr1590 error: unable to open port COM41 for programmer stk500v2
A possible candidate serial port is:
  -P COM41 or -P ch340
Note that above port might not be connected to a target board or an AVR programmer.
Also note there may be other direct serial ports not listed above.

avrdude_pr1590 done.  Thank you.

[Ho-Ro]

-c stk500v2 seems to support only baud rate of 115200.

Your observation is completely correct.
The setting -b only changes the baud rate of the PC, but the baud rate of the programmer is a constant value for this device that cannot be changed with a command from avrdude. The original STK500, for example, only uses 115200. If you set a different FW on the PC side, the communication will time out.

[mcuee]

This PR should be okay as I can see that default_baudrate value in avrdude.rc is effective.

PS>cat avrdude.rc
# Overall avrdude defaults; suitable for avrdude.rc

default_serial     = "COM4";
default_baudrate     = 57600;

#programmer # dryrun
#    id                     = "my_dryrun";
#    desc                   = "Emulates programming without a programmer";
#    type                   = "dryrun";
#    prog_modes             = PM_TPI | PM_ISP | PM_HVSP | PM_HVPP;
#;

PS>./avrdude_pr1590 -C ./avrdude_pr1590.conf -c avrispmkii -p m328pb -v

avrdude_pr1590: Version 7.2-20231214 (2662a2dc)
                Copyright the AVRDUDE authors;
                see https://github.com/avrdudes/avrdude/blob/main/AUTHORS

                System wide configuration file is C:\work\avr\avrdude_test\avrdude_bin\avrdude_pr1590.conf
                User configuration file is C:\work\avr\avrdude_test\avrdude_bin\avrdude.rc

                Using port            : usb
                Using programmer      : avrispmkII
                Default baud rate     : 57600
                AVR Part              : ATmega328PB
                Programming modes     : ISP, HVPP, debugWIRE, SPM
                Programmer Type       : STK500V2
                Description           : Atmel AVR ISP mkII
                Programmer model      : AVRISP mkII
                HW version            : 1
                Serial number         : 001D2C990079
                FW Version Controller : 1.24
                Vtarget               : 4.8 V
                SCK period            : 4.0 us
avrdude_pr1590: AVR device initialized and ready to accept instructions
avrdude_pr1590: device signature = 0x1e9516 (probably m328pb)

avrdude_pr1590 done.  Thank you.

[mcuee]

Testing again with git main and serialupdi, and it is working fine.

C:\work\avr\avrdude_test\avrdude_bin> cat avrdude.rc
# Overall avrdude defaults; suitable for avrdude.rc

default_serial     = "COM4";
default_baudrate     = 230400;

C:\work\avr\avrdude_test\avrdude_bin> .\avrdude -c serialupdi -P COM6 -p avr64dd32 -v

avrdude: Version 7.2-20231221 (06156d9c)
         Copyright the AVRDUDE authors;
         see https://github.com/avrdudes/avrdude/blob/main/AUTHORS

         System wide configuration file is C:\work\avr\avrdude_test\avrdude_bin\avrdude.conf
         User configuration file is C:\work\avr\avrdude_test\avrdude_bin\avrdude.rc

         Using port            : COM6
         Using programmer      : serialupdi
         Default baud rate     : 230400
         AVR Part              : AVR64DD32
         Programming modes     : UPDI, SPM
         Programmer Type       : serialupdi
         Description           : SerialUPDI
avrdude: device is in SLEEP mode
avrdude: NVM type 2: 24-bit, word oriented write
avrdude: entering NVM programming mode
avrdude: Chip silicon revision: 1.3
avrdude: AVR device initialized and ready to accept instructions
avrdude: device signature = 0x1e961a (probably avr64dd32)
avrdude: leaving NVM programming mode

avrdude done.  Thank you.

C:\work\avr\avrdude_test\avrdude_bin> .\avrdude -c serialupdi -P COM6 -p avr64dd32 -v -b 115200

avrdude: Version 7.2-20231221 (06156d9c)
         Copyright the AVRDUDE authors;
         see https://github.com/avrdudes/avrdude/blob/main/AUTHORS

         System wide configuration file is C:\work\avr\avrdude_test\avrdude_bin\avrdude.conf
         User configuration file is C:\work\avr\avrdude_test\avrdude_bin\avrdude.rc

         Using port            : COM6
         Using programmer      : serialupdi
         Overriding baud rate  : 115200
         AVR Part              : AVR64DD32
         Programming modes     : UPDI, SPM
         Programmer Type       : serialupdi
         Description           : SerialUPDI
avrdude: device is in SLEEP mode
avrdude: NVM type 2: 24-bit, word oriented write
avrdude: entering NVM programming mode
avrdude: Chip silicon revision: 1.3
avrdude: AVR device initialized and ready to accept instructions
avrdude: device signature = 0x1e961a (probably avr64dd32)
avrdude: leaving NVM programming mode

avrdude done.  Thank you.