| Author |
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Jeff M.
Guest
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 Posted:
Fri Feb 04, 2005 7:51 pm Post subject:
Intermittent Writing Error using PIC Bootloader |
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Hi, I am trying to get the Shane Tolmie v9.30 bootloader working with
my PIC 16F877A @ 20MHz and am encountering some strange problems. I am
able to program the bootloader into the chip no problem. When I try to
load the test program, I keep getting a "writing error". I sometimes
also get a communication timeout error, but this is much less frequent.
I keep doing this and eventually, I am able to complete the programming
successfully. When it fails, which is most of the time, it fails at
random points during the download. I have confirmed this same behavior
on a second chip I have.
In despiration, I tried this same experiment with the Tiny Bootloader
and had the same issue, fail most of the time, work once in awile. I
looked at my serial cable on a Scope and it looked ok. If anything, the
RS-232 data from the PC looked real good. The RS-232 data from the PIC
was not ideal, its peak to peak swing was about 3 volts lower then
expected. Also, the signals had a slope on them. The little I know
about RS-232, my signal should be well within the operating range.
Is there any debug commands in the windows bootloader software I can
use to further isolate this problem? Does anyone have any thoughts on
what this could be? Thanks for your help.
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malvarezdel
Guest
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| Posted:
Fri Feb 04, 2005 9:36 pm Post subject:
Re: Intermittent Writing Error using PIC Bootloader |
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| Have you WDT enabled? if itīs enabled, try disabling it. |
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Guy Macon
Guest
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| Posted:
Sat Feb 05, 2005 5:51 am Post subject:
Re: Intermittent Writing Error using PIC Bootloader |
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Jeff M. wrote:
| Quote: | Hi, I am trying to get the Shane Tolmie v9.30 bootloader
working with my PIC 16F877A @ 20MHz[snip]
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You will get better answers if you ask this question in the
comp.arch.embedded newsgroup.
Cheers!
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Memblers
Guest
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| Posted:
Sun Feb 06, 2005 9:55 pm Post subject:
Re: Intermittent Writing Error using PIC Bootloader |
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On 4 Feb 2005 05:51:56 -0800, "Jeff M." <mahon@syrres.com> wrote:
| Quote: | Is there any debug commands in the windows bootloader software I can
use to further isolate this problem? Does anyone have any thoughts on
what this could be? Thanks for your help.
|
I think the 16F877A requires program writes to be in multiples of some
amount (4 words, I think it was)). 16F877 doesn't require that.
I've used that bootloader with no problem here (haven't tried the 'A'
revision of that PIC though). |
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mike
Guest
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| Posted:
Mon Feb 07, 2005 6:08 am Post subject:
Re: Intermittent Writing Error using PIC Bootloader |
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Memblers wrote:
| Quote: | On 4 Feb 2005 05:51:56 -0800, "Jeff M." <mahon@syrres.com> wrote:
Is there any debug commands in the windows bootloader software I can
use to further isolate this problem? Does anyone have any thoughts on
what this could be? Thanks for your help.
I think the 16F877A requires program writes to be in multiples of some
amount (4 words, I think it was)). 16F877 doesn't require that.
I've used that bootloader with no problem here (haven't tried the 'A'
revision of that PIC though).
Bootloaders for the 877 and 877A are different because of this. |
You also have to strip out the configuration word so that the 4-word
write doesn't overwrite needed data. But that's not an intermittent
problem. Breaks every time...in my experience.
mike
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