Newbie question...

Started by clayforge June 28, 2003
I am new to the PIC chips, and I must admit to some confusion. I do
not understand what a bootloader does? I am planning on programming
the chips (16f84A) using PICBasic standard edition. Do I need the
bootloader?
Also, for a programming board, do I really need the $60 Epic
programmer, or can I use one of the programming boards I have seen
on eBay that costs about 1 quarter of that price.

I appreciate any input I can ge on this.

Thanks,

Scott




Hi,

Well basically a bootloader is a program that
resides at the end of your program memory. It receives
a downloaded program from a front-end application
onits USART pins. It then programs this user hex code
into the remaining part of program memory.

What it does is simple. The bootloader program uses
first 4 bytes of ur program memory 0x0000 - 0x0003
along with last 256 bytes of program memory. In the
first 4 byte locations a jump to last 256 bytes is
written. So whenever a chip is programmed with
bootloader is reset. The control first goes to the
0x0000 location then the jumps to last 255 bytes.
Here the bootloader program waits for around 0.2 sec
for any data on Usart pins. If it receives any data it
can program the flash memory internally.

For this it uses the PIC feature of internal flash
writing and reading.

With bootloader u can only work on certain chips say
16F87X series but if u want to program all pic series
u can go for a programmer which costs more.

A bootloader card will help u learn and test ur code
on
that micro-controller only.

U can even built ur on bootloader based hardware. This
bootloader program is freely available on net.

I hope this is help ful.

Sanjyot

--- clayforge <> wrote: > I
am new to the PIC chips, and I must admit to some
> confusion. I do
> not understand what a bootloader does? I am
> planning on programming
> the chips (16f84A) using PICBasic standard edition.
> Do I need the
> bootloader?
> Also, for a programming board, do I really need the
> $60 Epic
> programmer, or can I use one of the programming
> boards I have seen
> on eBay that costs about 1 quarter of that price.
>
> I appreciate any input I can ge on this.
>
> Thanks,
>
> Scott >
>
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Allow me to suggest the WISP628.
It's cheaper than most other programmer, and much better
in my opinion (Because it's an in circuit programmer,
you don't need to switch around the chips all the time).

Wouter van Ooijen developed and sells the WISP, and he also has a
great starter guide for new PIC users.
Check out his site :
http://www.voti.nl/swp/index.html

Good luck,
Shachar Weis.


> I am new to the PIC chips, and I must admit to some confusion.

read 'start with PICs' at http://www.voti.nl/swp

> I am planning on programming
> the chips (16f84A) using PICBasic standard edition.

If at all possible forget the f84, go for a 16F628 or 16F630 (or when
you have the money: a 16F877 or 18F452).

Wouter van Ooijen

-- -------
Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products



What is wrong with the F84?
> If at all possible forget the f84, go for a 16F628 or 16F630 (or
when
> you have the money: a 16F877 or 18F452).
>
> Wouter van Ooijen



it's old, they're phasing it out, and it's expensive. Grab a 16F628.
Glitchbuster.com has great pricing and cheap delivery.

Also you can look at the Olimex programmers for cheap . . . I bought
mine for $15. Check panderson's auctions on ebay.

I got going for the $15 programmer, a couple of chips, a serial cable,
the ICProgrammer software (free), the MPLab IDE software (free) and a
book. I think I spent more on the book than everything else combined.

Oh, also a breadboard or two and a well stocked junk box comes in handy
if you don't want a fancy proto/developer board. --- clayforge <> wrote:
> What is wrong with the F84? >
> > If at all possible forget the f84, go for a 16F628 or 16F630 (or
> when
> > you have the money: a 16F877 or 18F452).
> >
> > Wouter van Ooijen >


__________________________________




Nothing! But the 16F628 is the same size, cheaper, faster, has twice
the program memory, 3 times as much ram, twice as much eeprom, has
analog comparators, a USART and a lot more capability.

Other than that they are similar... --- In , "clayforge" <festave@t...> wrote:
> What is wrong with the F84? >
> > If at all possible forget the f84, go for a 16F628 or 16F630 (or
> when
> > you have the money: a 16F877 or 18F452).
> >
> > Wouter van Ooijen