Byron,

My application has 2 separate coms ports. The UART is used for radio link
coms and the bit-bashed link is used for coms to a PC or another micro
controller.

The uploading of new software must share the bit-bashed coms with whatever
is used to control the device via commands on the bit-ashed coms.

Regards

David Huisman

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Wollenberg, Frank
Sent: Wednesday, July 04, 2001 12:59 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]:Specific Bootloader required


On Tuesday, July 03, 2001 3:39 PM, David Huisman wrote:

> I need to use that same port pin
> in my application though during running of the user code. ie.
> The Bit-Bashed com port has a dual function.
> !) Bootloader upload of new user program,
> 2) Bi-directional serial com link.

David,

i'm developing a bootloader over the internal USART. The USART is used in my
application (--> RS485), but i must be able to download a new firmware over
the same bus. This is analog to your problem. A BREAK condition is used to
signal the start of bootloading. This is done in my application USART
service. On detection the PIC starts the bootloading. Before i will
overwrite my old firmware, i must receive a preamble. If this doesn't occur,
the PIC resets.

After power-up, the PIC validate his firmware. On success the PIC starts my
application. If failed, the PIC checks for the BREAK condition.
After that the PIC continues as described above.

I think you can do the same concept of BREAK condition for signaling a
bootloading request.

Frank

-------------------------------------

GSP Sprachtechnologie GmbH
Frank Wollenberg
HW-Entwicklung
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eMail:  f.wollenberg@gsp-berlin.de



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