> On 04/02/14 19:51, Tim Wescott wrote:
>> On Tue, 04 Feb 2014 12:19:29 -0600, prashanthgr.1992 wrote:
>>
>>> 2. Why we need bootloader? What is the use of bootloader although we ve
>>> debuggers for programming?
>>
>> You don't _need_ a bootloader, per se. Often if you've got some really
>> big software load (like linux with applications, or VxWorks, etc.) a
>> bootloader makes your life easy.
>>
>> A shippable product does not have a debugger attached to it, any more
>> than your average 18 year old kid still has an umbilical cord.
>>
>
> I made a shipping product with a debugger still attached. I used an
> FTDI 2232C chip with one channel connected to the microcontroller's UART
> (for normal PC to board communication while running), and the other as a
> JTAG-style connection (BDM, to be accurate) to the microcontroller.
> While it didn't support full debugging, it supported "programming over
> the debugger" from the PC for downloading and updating the software. It
> worked very well, and is a method I could well use again - especially
> for ARM chips with OpenOCD running on the PC side.
>
>
Do you mean "shipped" as in "run at a test site" or "as production"?
Having an end customer run a debugger at boot time*, or
even at update time seems troublesome.
*not that you said you did that; it's a bit ambiguous.
Even on stuff with 68000 or Codlfire-in-68000, long as there's FLASH
memory for program storage, I've mainly seen people write program
loaders over a 232 port for going on 25 years now.
Even better; have a filesystem in FLASH.
--
Les Cargill
Reply by Les Cargill●February 8, 20142014-02-08
prashanthgr.1992, you need help on the ground.
The non-snark version:
prashanthgr.1992 wrote:
> Hi all,
> I am new to Embedded design industry.
> I have some questions regarding C and bootloader.
> 1. What is the use of pointers, function pointers, structures, structure
> pointer, array of structures, array of pointers, unions with respect to
> embedded programming?
Those are just elements of 'C' programming and not constrained to embedded.
> 2. Why we need bootloader? What is the use of bootloader although we ve
> debuggers for programming?
> Les Cargill <lcargill99@comcast.com> writes:
>
>> prashanthgr.1992 wrote:
>>> Hi all,
>>> I am new to Embedded design industry.
>>
>> Get out while you can.
>>
>>> I have some questions regarding C and bootloader.
>>> 1. What is the use of pointers, function pointers, structures, structure
>>> pointer, array of structures, array of pointers, unions with respect to
>>> embedded programming?
>>
>> Yes!
>>
>>> 2. Why we need bootloader? What is the use of bootloader although we ve
>>> debuggers for programming?
>>
>> You don't need it since you use debugger.
>>
>>> 3. Why PBL and SBL?? Why not a single memory?
>>>
>>
>> Some memory is more equal than other.
>
> Vladimir, come back, we need you...
>
Very much so :)
--
Les Cargill
Reply by John Devereux●February 8, 20142014-02-08
Les Cargill <lcargill99@comcast.com> writes:
> prashanthgr.1992 wrote:
>> Hi all,
>> I am new to Embedded design industry.
>
> Get out while you can.
>
>> I have some questions regarding C and bootloader.
>> 1. What is the use of pointers, function pointers, structures, structure
>> pointer, array of structures, array of pointers, unions with respect to
>> embedded programming?
>
> Yes!
>
>> 2. Why we need bootloader? What is the use of bootloader although we ve
>> debuggers for programming?
>
> You don't need it since you use debugger.
>
>> 3. Why PBL and SBL?? Why not a single memory?
>>
>
> Some memory is more equal than other.
Vladimir, come back, we need you...
--
John Devereux
Reply by Les Cargill●February 8, 20142014-02-08
prashanthgr.1992 wrote:
> Hi all,
> I am new to Embedded design industry.
Get out while you can.
> I have some questions regarding C and bootloader.
> 1. What is the use of pointers, function pointers, structures, structure
> pointer, array of structures, array of pointers, unions with respect to
> embedded programming?
Yes!
> 2. Why we need bootloader? What is the use of bootloader although we ve
> debuggers for programming?
> On Tue, 04 Feb 2014 12:19:29 -0600, prashanthgr.1992 wrote:
>
>> 2. Why we need bootloader? What is the use of bootloader although we ve
>> debuggers for programming?
>
> You don't _need_ a bootloader, per se. Often if you've got some really
> big software load (like linux with applications, or VxWorks, etc.) a
> bootloader makes your life easy.
>
> A shippable product does not have a debugger attached to it, any more
> than your average 18 year old kid still has an umbilical cord.
>
I made a shipping product with a debugger still attached. I used an
FTDI 2232C chip with one channel connected to the microcontroller's UART
(for normal PC to board communication while running), and the other as a
JTAG-style connection (BDM, to be accurate) to the microcontroller.
While it didn't support full debugging, it supported "programming over
the debugger" from the PC for downloading and updating the software. It
worked very well, and is a method I could well use again - especially
for ARM chips with OpenOCD running on the PC side.
Reply by David Brown●February 5, 20142014-02-05
On 04/02/14 19:19, prashanthgr.1992 wrote:
> Hi all,
> I am new to Embedded design industry.
When you have homework questions, be honest about them. You are a
/long/ way from being in any industry as yet.
Reply by Simon Clubley●February 4, 20142014-02-04
On 2014-02-04, Grant Edwards <invalid@invalid.invalid> wrote:
> On 2014-02-04, prashanthgr.1992 <99090@embeddedrelated> wrote:
>
>> 3. Why PBL and SBL?? Why not a single memory?
>
> Don't know what you mean by that either.
>
Given the context from the other questions, my _guess_ would be the
OP means Primary Boot Loader and Secondary Boot Loader.
My _guess_ would be the PBL is the on-chip boot ROM and the SBL is
something like the U-Boot SPL loader.
Simon.
--
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world
Reply by Wouter van Ooijen●February 4, 20142014-02-04
Grant Edwards schreef op 04-Feb-14 7:36 PM:
>> 2. Why we need bootloader?
>
> Maybe you don't. Some platforms use them, some don't. Whether you
> need one or not depends on your hardware and software architecture.
> Small embedded systems often don't have a bootloader.
You interpret the term 'bootloader' as a minimal piece of software that
always gets control at startup, and is responsible for the loading of
the 'real' application.
There is another interpretation, mainly for small microcontrollers with
flash memeory. In this case the bootloader is a small piece of software
that CAN be run at startup to load new content for the flash over some
communication link, after which the chip can be reset another time, this
time enabling the (new) application in flash.
This second form of bootloader is very common on small micronctrollers,
for instance all LPC ARM/Cortex UC's I know have a built-in serial
bootloader, and some have an additional bootload option over CAN or USB.
For this interpretation, an answer could be 'to facilitate in-field
software updates'.
Wouter
Reply by Tim Wescott●February 4, 20142014-02-04
On Tue, 04 Feb 2014 12:19:29 -0600, prashanthgr.1992 wrote:
> Hi all,
> I am new to Embedded design industry.
> I have some questions regarding C and bootloader.
> 1. What is the use of pointers, function pointers, structures, structure
> pointer, array of structures, array of pointers, unions with respect to
> embedded programming?
Mostly the same as desktop programming, although on a small embedded
application your usage of all that is heavily shaped by the fact that you
don't have a lot of memory or processor time to waste.
> 2. Why we need bootloader? What is the use of bootloader although we ve
> debuggers for programming?
You don't _need_ a bootloader, per se. Often if you've got some really
big software load (like linux with applications, or VxWorks, etc.) a
bootloader makes your life easy.
A shippable product does not have a debugger attached to it, any more
than your average 18 year old kid still has an umbilical cord.
> 3. Why PBL and SBL?? Why not a single memory?
Presumably you are asking a question about a specific processor or
board. This may sound odd, but not everyone here has used everything
available. Perhaps this has to do with people having finite lifetimes.
I suggest you either tell us more about what PBL and SBL are, or that you
study the documentation for the product in which you've found those terms
and see if you can figure it out for yourself.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com