2011-03-22, 10:51:48
(This post was last modified: 2012-12-22, 13:44:31 by Mikael Gustavsson.)
(Chip mostly 33FJ128MC510, some MC804s)
I'm looking into the loader for a work related application.
The strong points are the low degree of mutation to existing projects, the checksum/verify options, PC tooling (pity about the .NET though, will have to install .NET onto our legions of XP machines in the field) and basic protection. Also the general cleanliness impresses.
We want the bootloader protection to prevent user error btw, not so much for IP protection, so while hw protection using Codeguard looks interesting, it seems one then always needs the boot segment first in memory, requiring linker file adaption? Is that why dsloader doesn't implement it?
The first issue however is the prominent GPL license. I worry/wonder about the wellknown viral clause of this license. E.g. combining a project of bootloader with application would then "link" both into the same file, thus invoking the GPL viral clause. One could probably discuss if this really constitutes linking, but if such limitations are not the purpose of the license, some clarification would be nice. (and I suggest LGPL instead of GPL).
Since I'm more confortable with C then with dsPIC 16-bit assembler, I wonder if sb managed to do the initialization (of e.g. oscillators) in C. Otherwise, I'll have to learn yet another assembler language:-)
Another mod I'll need is to only go into bootloader if a button is pressed on startup. This because because the PC and controller are 30 meters apart (rs422), and I thus need a long timeout (30s+ or even near indefinitely) to allow for walking. To avoid an accidental power outage triggering a long timeout, I only want to enter bootloader mode when the button is held.
If sb has already done something like that, I'd be grateful. (mostly to look at the assembler, I know how to do it in C)
I'm looking into the loader for a work related application.
The strong points are the low degree of mutation to existing projects, the checksum/verify options, PC tooling (pity about the .NET though, will have to install .NET onto our legions of XP machines in the field) and basic protection. Also the general cleanliness impresses.
We want the bootloader protection to prevent user error btw, not so much for IP protection, so while hw protection using Codeguard looks interesting, it seems one then always needs the boot segment first in memory, requiring linker file adaption? Is that why dsloader doesn't implement it?
The first issue however is the prominent GPL license. I worry/wonder about the wellknown viral clause of this license. E.g. combining a project of bootloader with application would then "link" both into the same file, thus invoking the GPL viral clause. One could probably discuss if this really constitutes linking, but if such limitations are not the purpose of the license, some clarification would be nice. (and I suggest LGPL instead of GPL).
Since I'm more confortable with C then with dsPIC 16-bit assembler, I wonder if sb managed to do the initialization (of e.g. oscillators) in C. Otherwise, I'll have to learn yet another assembler language:-)
Another mod I'll need is to only go into bootloader if a button is pressed on startup. This because because the PC and controller are 30 meters apart (rs422), and I thus need a long timeout (30s+ or even near indefinitely) to allow for walking. To avoid an accidental power outage triggering a long timeout, I only want to enter bootloader mode when the button is held.
If sb has already done something like that, I'd be grateful. (mostly to look at the assembler, I know how to do it in C)