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In-System Programming Support => P89V51Rx2/P89LV51Rx2 => Topic started by: MX21 on September 29, 2011, 10:59:40 AM

Title: How do I change a chip from 6-clock mode back to 12-clock mode?
Post by: MX21 on September 29, 2011, 10:59:40 AM
I've got some boards that have P89LV51RD2 chips that somehow got the 6-clock (double clock) bit set.  How do I clear that?  Tried resetting, erasing all flash, etc.  There's an ISP command to set 6-clock mode, but no command to clear it.
Title: Re: How do I change a chip from 6-clock mode back to 12-clock mode?
Post by: Andy Ayre on September 29, 2011, 09:13:18 PM
You will have to check the user manual for the device from NXP. I don't have it to hand but for some devices it requires a parallel programmer and for others it is a one-way fuse and cannot be reversed.

Andy
Title: Re: How do I change a chip from 6-clock mode back to 12-clock mode?
Post by: MX21 on October 03, 2011, 11:19:01 AM
Quote from: Andy Ayre on September 29, 2011, 09:13:18 PM
You will have to check the user manual for the device from NXP. I don't have it to hand but for some devices it requires a parallel programmer and for others it is a one-way fuse and cannot be reversed.

Andy

I checked the datasheet, but I haven't been able to find any mention that you can't clear the double clock mode bit using ISP. 
Title: Re: How do I change a chip from 6-clock mode back to 12-clock mode?
Post by: Andy Ayre on October 04, 2011, 08:35:17 PM
If it doesn't explicitly say that you CAN clear it using ISP then you can't. Flash Magic only supports the commands listed in the NXP user manual. Sorry.

Andy
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