How to remove Bootloader for instant startup?

Projects General Guidance
1

Sorry, I am still new to this.

I have a couple of Arduino Nanos here and for my current project I'd need to start up the Nano immediately when powered (no boot time, if possible).

I tried to follow this video to connect two Nanos (removing the Bootloader and using one to program the other) but ran into a problem:

Most Nanos show the writing "ICSP" next to those six pins that are used to do so. Mine do not (see photo). Do these pins have the same functionality as shown in the video then or do I have to use any other pins instead?

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I also couldn't find examples of using two Nanos, there always seem to be at least one Uno involved - is this mandatory or can this be done with two Nanos as well?

2

The 6 pins are the ICSP header but note that each of the pins is connected to another pin on the board which can be used instead

You can remove the bootloader by uploading a sketch using the ICSP pins and a programmer

More correctly, that does not remove the bootloader but stops it being invoked on subsequent resets, so there is no waiting to see whether a sketch is going to be uploaded using the serial interface which is what causes the delay

You can use one Nano to program another as in most respects the Nano and Uno are functionally equivalent

3

Best to buy an icsp programmer , really cheap
and easier to use than configuring another Arduino and loading its software .

Beware that if you program this way you will need to reload the bootloader if you again want to program via the USB.

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1 Like
4

You don't have to use the header, you can connect directly to the req'd pins.

image

5

If the nano is using the current boot loader (not the “old boot loader”) there should not be much delay. The first thing the boot loader does is check to see if the processor was reset from a power up, and if so goes immediately to the user sketch.

1 Like
6

@JohnRob: I am able to find the GND, 5V, RST pins on the Nano, of course - but what pins are the MOSI, MISO and SCK pins (if not using the header)?

Is this
11 (MOSI)
12 (MISO)
13 (SCK)?

So to when using two Nanos (ATMega328P, Old Bootloader), the wiring would look like this?

Bild6
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7

Yes

8

Hm, I can't get it to work for some reason :face_with_diagonal_mouth:

Here's what I am doing:

  • Using two Nanos (ATMega328P, Old Bootloader)
  • Connect the programmer to the PC via USB
  • Open the IDE, go to "Examples" -> ArduinoISP and upload this sketch
  • Then connecting the target to the programmer exactly as shown in my last image (post #6)
  • Connect programer to PC again.
  • Open the sketch I want to upload to the target.
  • Select "Tools" -> "Programmer" -> "Arduino as ISP"
  • Select "Sketch" -> "Upload with programmer"

After a couple of seconds I get this console error message:

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x15
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x15

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x14

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x01
avrdude: stk500_initialize(): (a) protocol error, expect=0x14, resp=0x10
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.

avrdude: stk500_disable(): unknown response=0x12

Also tried selecting
"Tools" -> "Programmer" -> "Arduino as ISP (ATMega32U4)" from the list, but same results.

Double checked connections - seems ok. Is it because my boards are china clones?

9

The "minicore" GitHub - MCUdude/MiniCore: Arduino hardware package for ATmega8, ATmega48, ATmega88, ATmega168, ATmega328 and ATmega328PB allows you to select a "no bootloader" option for the target. You still have to select "burn bootloader" to set the fuses correctly even though you don't want a bootloader.

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10

Do you have a capacitor between the reset pin and ground on the board being used as the programmer?

Can you post a picture showing your wiring?

11

I would just say that in my experience the bootloader does not cause any material delay unless USB is actually connected. If it is connected, there will be a negotiation, but otherwise I think it just goes directly to your sketch. But you can test that.

12

If you ICSP upload code to the AVR, it will remove the bootloader.
i.e. there will no longer be a bootloader and a application, there will only be an application and the reset vector will jump to the gcc startup code in the sketch.

--- bill

13

If you are using the optiboot bootloader, which I think you are, then the bootloader does not cause delay on powerup or watchdog reset.
The first thing it does is check to see if the AVR is starting up from a power up or a reset. If it is not a pin reset it will jump directly to the application code (your sketch).
If it is a pin reset, then the bootloader will flash the on board LED an then monitor the serial port for an upload. After 1/2 second it will jump to the application code.
You can test this by looking at the on board LED and see the behavior difference when you power it up vs reset it by pushing the reset button.

If all you want/need is a fast startup from a power up, you essentially already have it. I say "essentially" because there are few instructions that do get executed,
I'd have to look at the actual bootloader code but I'd guess that it is going to be on the order of 1us
So if you eliminated the bootloader you would only save about 1us on powerup or watchdog reset.
On reset, yes, it would make a difference but not much on powerup.

--- bill

14

@2KBastler
Hi. You might also find this article interesting:

15

@david_2018: I uploaded a picture of my wiring - see post #6. No, I did not add a capacitor - I've never seen that in the diagrams I've seen so far. Is this mandatory? What type of capacitor should be used?

@bperrybap: No, I am not using Optiboot firmware - both Nanos are common ATMega china clones with old bootloader, as far as I know. All I want is a quick startup (current boot time is ~2.5 seconds)

16

Bill, you know much more than I do about these things, but is the bootloader actually removed by the process of uploading using ICSP or is it more accurate to say that after such an upload then the bootloader code is not executed on startup ?

Experiments uploading the same code via Serial and ICSP show that using ICSP does not make any more memory available.

17

The fuses have to be changed to free up the area reserved for the bootloader. From AVR Fuse Calculator for ATmega328P :

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EDIT

And this is an extract from the minicore boards.txt for the ATmega328 showing that the high fuse is set to 0xD7 when the user selects no bootloader

328.menu.bootloader.no_bootloader=No bootloader
328.menu.bootloader.no_bootloader.upload.maximum_size=32768
328.menu.bootloader.no_bootloader.bootloader.high_fuses=0xd7   <<<<<<<
328.menu.bootloader.no_bootloader.bootloader.file=empty/empty.hex

The full file is here is attached
boards.txt (21.9 KB)

18

You uploaded a diagram of how the wiring should be, I was requesting a picture of the actual boards and wiring, to see if you had made any mistakes.

The capacitor generally is around 10uF, and goes between the reset pin and ground on the arduino that is being used as the programmer. The purpose is to prevent the arduino from resetting if the computer resets the serial connection during the programming process.

19

@david_2018 : Do you mean a capacitor between D10 (wich is connected to RST on the target) and GND or RST (wich is not used on the programmer) and GND? That's a bit confusing for me.

Anyway, here's my wiring:

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photo5332343902943953854
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Which always results in this error message:

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x15
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x15

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x14

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x01
avrdude: stk500_initialize(): (a) protocol error, expect=0x14, resp=0x10
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.

avrdude: stk500_disable(): unknown response=0x12
20

The capacitor goes between RST on the programmer and GND, not the connection on D10.