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Atmel AT89c51RB2 Bootloader circuit

Started by donald March 19, 2008
I have built the FLIP compatable circuit from the
C51_Hardware_Connections.pdf app note (Page 2).

But, I always get a time out from the RB2 chip.

Has anyone build this circuit successfully?

I am using a 32Mhz crystal on the RB2.

thanks

donald
On Wed, 19 Mar 2008 14:46:17 -0700, donald <Donald@dontdoithere.com>
wrote:

>I have built the FLIP compatable circuit from the >C51_Hardware_Connections.pdf app note (Page 2). > >But, I always get a time out from the RB2 chip. > >Has anyone build this circuit successfully? > >I am using a 32Mhz crystal on the RB2.
Try to sync no faster than 9600 baud. Also, check page 93 of the chip's datasheet for the proper sequencing of the signals necessary for the chip to enter ISP mode. <http://www.atmel.com/dyn/resources/prod_documents/doc4180.pdf> The default state of the BLJB is to vector to the bootloader on reset, so if it's a new chip then the bootloader is running but you're probably trying to connect at too high a speed. If BLJB has been programmed, then the only way to get to the bootloader is the dance with RESET and PSEN. -- Rich Webb Norfolk, VA
Rich Webb wrote:
> On Wed, 19 Mar 2008 14:46:17 -0700, donald <Donald@dontdoithere.com> > wrote: > >> I have built the FLIP compatable circuit from the >> C51_Hardware_Connections.pdf app note (Page 2). >> >> But, I always get a time out from the RB2 chip. >> >> Has anyone build this circuit successfully? >> >> I am using a 32Mhz crystal on the RB2. > > Try to sync no faster than 9600 baud. Also, check page 93 of the > chip's datasheet for the proper sequencing of the signals necessary > for the chip to enter ISP mode. > <http://www.atmel.com/dyn/resources/prod_documents/doc4180.pdf> > > The default state of the BLJB is to vector to the bootloader on reset, > so if it's a new chip then the bootloader is running but you're > probably trying to connect at too high a speed. If BLJB has been > programmed, then the only way to get to the bootloader is the dance > with RESET and PSEN. >
I thought 19200 was slow enough, but 9600 worked. Thanks donald