| Author |
Message |
|
|
 Posted: Aug 20, 2007 - 09:36 PM |
|
Joined: Sep 04, 2002
Posts: 17683
Location: Orlando Florida
|
|
| I have 128 words free in my mega16 (256 bytes). Is there a bootloader that will fit? I know BLIPS and Megaload will fit in 256 words... Not matter what I try, I can't squeeze it down enough to have 256 words free.... |
_________________
Imagecraft compiler user
Last edited by bobgardner on Jan 28, 2011 - 06:00 PM; edited 1 time in total
|
| |
|
|
|
|
|
|
Posted: Aug 20, 2007 - 09:44 PM |
|
Joined: Feb 19, 2001
Posts: 22734
Location: Wisconsin USA
|
|
Where is HWMNBN when we need him?
If it weren't the tiniest bootloader, I'd suggest using proven routines common to the main code (U(S)ART driver routines come to mind) as bootloader-resident and share with the main code. But I suspect that with 128 words you'll need very tight crafting.
[There is always the Compiler Wars answer, but there are other threads for that.  ]
Lee |
|
|
| |
|
|
|
|
|
|
Posted: Aug 20, 2007 - 09:58 PM |
|
Joined: Jun 04, 2007
Posts: 1075
Location: Cincinnati, Ohio - USA
|
|
| Will you be using the UART? I have bootloader written in assembler that I believe would fit. I'll need to double check it though. |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 09:35 AM |
|
Joined: Sep 20, 2003
Posts: 3419
Location: Surrey, England
|
|
| The first bootloader I "wrote" (actually I started from the Megaload program, stripped off the stuff I didn't need and re-wrote it in assembler) ran in 149 words, so I suspect it's possible to write one in 128 words. Mine didn't handle EEPROM, just Flash. |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 01:07 PM |
|
Joined: Jun 04, 2007
Posts: 1075
Location: Cincinnati, Ohio - USA
|
|
The version I have that would fit is for a Tiny2313 which only handles Flash. Full functionality could fit if a custom protocol is used instead of AVR109 type.
I have one I started some time ago but never did get around to finishing it. |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 01:18 PM |
|
Joined: Jul 18, 2005
Posts: 50115
Location: (using avr-gcc in) Finchingfield, Essex, England
|
|
Talking of protocols, what protocol do people implement to handle packet flow control (telling the PC to stop while a page is being erased/written)? Also what do you do about data validity (checksums/CRCs etc.)? Is the code, for example, trying to decode intel hex or is it packetised-binary at the stage it reaches the AVR?
I'm just wondering what would be optimal to keep the AVR hosted bit of the process as small as possible (but still workable!)
Cliff |
_________________
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 03:28 PM |
|
Joined: Oct 03, 2001
Posts: 217
Location: NYC, USA
|
|
The xmodem bootloaders look pretty small.
could not find this here on freaks, but the web link looks okay.
http://www.ejberg.dk/temp/boot16.zip
Not sure who to credit though.
-carl |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 04:02 PM |
|
Joined: Jun 04, 2007
Posts: 1075
Location: Cincinnati, Ohio - USA
|
|
|
Quote:
The xmodem bootloaders look pretty small.
While being small it still looks to be about 350 bytes.
Quote:
Talking of protocols, what protocol do people implement to handle packet flow control (telling the PC to stop while a page is being erased/written)? Also what do you do about data validity (checksums/CRCs etc.)
As long as there is a way to read back the contents to be verified I don't really see any need for checksums or CRCs in most cases. I think it's been hard for many to let go of this concept since these days it has a much more limited use. It was originally used because it was more efficient to check individual packets of data so as to not need to retransmit all of the data if there only happened to be one bit of corrupted data and you are transmitting at a blazing 300 baud 
As far as waiting for a block to finish I would usually just wait for an acknowlegement from the AVR after each packet with a timeout on the PC side to avoid getting stuck in limbo should something go wrong.
The one protocol I had been working on basically puts all of the overhead on the PC side in order to keep things small on the Avr side. If I get time this week I'll try to finish things up and post them here. |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 04:21 PM |
|
Joined: Oct 03, 2001
Posts: 217
Location: NYC, USA
|
|
|
Quote:
While being small it still looks to be about 350 bytes.
Dang,
I just looked at the the hex file and questimated it at about 275 bytes. But actually loading and compiling does it come out @ 175 words.
Too much to shave down to 128 words.
Well if you also have the option to write the host side software, you should be able to squeeze it in.
Sorry for the misfire,
-carl |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 04:28 PM |
|
Joined: Feb 19, 2001
Posts: 22734
Location: Wisconsin USA
|
|
DigiKey:
Mega16: $6.45/qty. 1; $3.75/qty. 100
Mega324: $6.02/qty. 1; $3.98/qty. 100
Maybe if you were making 1M of the devices, you would save $230000. If you are making 10, then you lose $4.30. If you are making 100, then you save $23.00. Is your time worth it to squeeze into the Mega16?
Lee |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 05:16 PM |
|
Joined: Sep 04, 2002
Posts: 17683
Location: Orlando Florida
|
|
| I've got 500 of em with a mega16. The bad thing is I need to remove 2 screws and remove the back plate to access the jtag, so I have a motivation to get some sort of serial loading working. See mcnallyelectronics.com for the front view.... back view has an 8 pin connector |
_________________
Imagecraft compiler user
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 05:32 PM |
|
Joined: Jul 18, 2005
Posts: 50115
Location: (using avr-gcc in) Finchingfield, Essex, England
|
|
So do any of the "C vs Asm" veterans want to step up to the plate to see exactly how small a bootloader could be made? In C I think one will have to disable the auto-generation of vector tables and the preamble stuff to copy global inits and wipe non-init globals. But first a protocol for data transmission needs to be agreed. Anything non-standard is going to need a special PC app written while any of AVR109, Xmodem, IntelHex or whatever maybe has unnecessary protocol overhead "baggage" to contend with. Do you, for example, need EEPROM programming or is flash alone OK?
Cliff |
_________________
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 05:47 PM |
|
Joined: Jun 26, 2001
Posts: 825
Location: Silkeborg, Denmark
|
|
If it doesn't have to be AVRISP compatible, I'm pretty certain tinyloader 1.3 (tinyloader.kasperkp.dk/r13.zip) could be modified for M16 and still fit in 64 words.
Most of the intelligence of that loader is pushed onto the PC app in order to hit a 48 word target for Tiny13. |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 06:13 PM |
|
Joined: Feb 14, 2007
Posts: 1858
Location: San Diego California
|
|
|
clawson wrote:
So do any of the "C vs Asm" veterans want to step up to the plate to see exactly how small a bootloader could be made? In C I think one will have to disable the auto-generation of vector tables and the preamble stuff to copy global inits and wipe non-init globals. But first a protocol for data transmission needs to be agreed. ...?
Cliff
OH Yes, please do!!! Is the game on?
Great idea Cliff,
John
Edited:
John (js) Lennart and the rest of the 'secret order' you have just been challenged!!! Are you sissies or what? |
_________________
Resistance is futile…… You will be compiled!
Last edited by AllN on Aug 21, 2007 - 06:17 PM; edited 2 times in total
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 06:14 PM |
|
Joined: Nov 30, 2001
Posts: 502
Location: Golden, CO (used to be Chile)
|
|
I have a bootloader that should fit in 256 bytes. It is heavily based in Design Note 32. It should work with avrprog. I also have a program written in Python to download the program to the AVR.
Let me know if you are interested. |
_________________
Regards,
Alejandro.
http://www.ocam.cl
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 07:14 PM |
|
Joined: Feb 19, 2001
Posts: 22734
Location: Wisconsin USA
|
|
|
Quote:
So do any of the "C vs Asm" veterans want to step up to the plate to see exactly how small a bootloader could be made?
<grin> As a matter of fact, I was looking at BLIPS and it has a few words of "slack" left in 256 words. I was going to do a quick C translation to see how it comes out. My compiler knows about "bootloader" apps, so some of the preamble, vector, etc. should be OK. A critical factor for pure C might be if it is critical to keep Z loaded and then do Z+ type of stuff. My compiler uses Z as its primary working register, and I'm guessing that I may end up with a lot of re-loading and thus blow it up a bit. My temptation would be to just implement for my desired target (Mega88) and only do page mode.
If I get the time to keep playing with it I'll post my results.
Actually the Tinyloader is so simple that the C version may not be much different--gotta look at it to see if there are any gotchas. Amazing work.
Lee |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 07:27 PM |
|
Joined: Feb 14, 2007
Posts: 1858
Location: San Diego California
|
|
Well ˝ of the challenge as been accepted!!
(and the most beautiful cheerleader you ever saw sing.)
Yeah Lee he our MAN if he can’t do it NO ONE can!
Yeaaaaaaaaaaaaaaaaaaaah Lee!
What fun,
John |
_________________
Resistance is futile…… You will be compiled!
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 07:48 PM |
|
Joined: Nov 30, 2001
Posts: 502
Location: Golden, CO (used to be Chile)
|
|
I left the bootloader and the PC application in http://www.ocam.cl/avrpybl .
I plan to release the bootloader in the future as open source. It needs some improvements yet, but it should work. |
_________________
Regards,
Alejandro.
http://www.ocam.cl
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 08:26 PM |
|
Joined: Jun 26, 2001
Posts: 825
Location: Silkeborg, Denmark
|
|
(looks around, spots a suitable M16 target)
If nothing unexpected arrives this weekend, for the fun of it, I'll look at an M16 version of Tinyloader;
Lee, I have a suspicion that the input to a C compiler that generates a tinyloader-like output is going to look like anything but C - for something like this there isn't what C is so often claimed to be by definition: A platform-independent, portable implementation. But, please prove me wrong, and I will provide support if you need a different PC side tool.
oh, and adding the whole thing into the peephole optimizer counts as cheating.
Kasper |
|
|
| |
|
|
|
|
|
|
Posted: Aug 21, 2007 - 08:39 PM |
|
Joined: Mar 23, 2001
Posts: 2081
Location: Halifax, NS
|
|
Hello,
If you have a Dataflash on the application, you can have a simple bootloader that loads from the dataflash. Then the real bootloader is stored in the dataflash... you can really cram down the size then!
-Colin |
_________________
VA3 YHZ - http://www.newae.com
|
| |
|
|
|
|
|
FAQ
Search
Register
Log in to check your private messages
Log in
Maximize
RSS
