Author Topic: How to reprogram ISP mode entry  (Read 4692 times)

SARAVANAN

  • Jr. Member
  • **
  • Posts: 2
    • View Profile
How to reprogram ISP mode entry
« on: July 18, 2013, 03:32:37 am »
Hi,

        I have got an 89V51RD2BN dev board and unfortunately I programmed the ISP mode entry to run user code, thinking that I can reprogram it to run boot loader later. But now I couldnt enter ISP mode and no autobaud happens. So is there any way I can return back other than a parallel programmer??? Thanks

Andy Ayre

  • ESAcademy Staff
  • Sr. Member
  • *****
  • Posts: 2172
    • View Profile
    • Embedded Systems Academy, Inc.
    • Email
Re: How to reprogram ISP mode entry
« Reply #1 on: July 19, 2013, 12:43:48 am »
After reset there is about a 400ms window in which to send a 'U' to the RxD pin. If the device detect the 'U' then it enters the bootloader.

Andy
Embedded Systems Academy, Inc.
support at esacademy dot com

SARAVANAN

  • Jr. Member
  • **
  • Posts: 2
    • View Profile
Re: How to reprogram ISP mode entry
« Reply #2 on: July 29, 2013, 03:05:18 am »
Thanks for the reply

will try it out.

Thanks again