Author Topic: Help me with my P89C51RD2BA...  (Read 8365 times)

Do Hong Phuc

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Help me with my P89C51RD2BA...
« on: May 04, 2003, 11:32:07 am »
I have P89C51RD2BA with a basic board (RS232 IC, 11.0592Mhz crystal, power supply ...). When I connects it to COM2 port and uses WinISP to detect my P89C51RD2BA, it promtps: "Invalid Response to 'U'.-->" . I've chosen parameters: P89C51RD2, COM2, 11.0592 Mhz. And I've also follow its instruction: "Press RESET button while keep PSEN low before use WinISP".

Please help me, I can't use my P89C51RD2BA (until now!). How can I know whether my P89C51RD2BA is died or not?

Thank you very much.

Andy Ayre

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Re: Help me with my P89C51RD2BA...
« Reply #1 on: May 05, 2003, 08:31:29 am »
Please try using Flash Magic and see if that helps. If it does not then at least we can make more progress tracking down the problem as Flash Magic features a debugging mode, while WinISP does not.

If you also run into problems using Flash Magic, then please read through and complete the steps in Flash Magic Application Note 4.

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David Cockerell

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Re: Help me with my P89C51RD2BA...
« Reply #2 on: July 17, 2003, 08:51:54 am »
I have a similar problem to Do Hung Phuc.  FlashMagic says it cannot communicate with P89C51RC2BA.  The indications are that the chip is
not getting into ISP mode despite receiving all the correct signals at
RST NPSEN and VPP  (according to AN461).
  There is an errata note, es_89c51rx2_01_090402.pdf, which confesses
to this problem.    It says:
"If a Power-On Reset is applied to the device while the PSEN pin is held low, the part will not enter ISP mode as expected but executes user code instead."  
  The note goes on to suggest some workarounds with resistors and
capacitors on the Vpp and NPSEN pins but does not explain how they
work.    So far I have not been able to get them to work.
   If anyone knows how to get P89CRC51RC2BA into ISP mode I would
be very happy to hear how.

Dong-Liang Shiue

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Re: Help me with my P89C51RD2BA...
« Reply #3 on: July 28, 2003, 03:14:33 am »
Hi, Do Hong Phuc
P89C51RD2BA and P89C51RD2HBA are different devices.
Winisp don't support  P89C51RD2BA.
So, You can try for using Flash Magic.

I think, You can use parallel programmer to read Boot Vector and Status Byte value. The Normal value is Boot Vector=0xFC and Status Byte=0x00. If the value is not correct. Then you can use parallel programmer to reprogram. Otherwise, You can erase all memory including Security Bits.

I hope this may be helpful !


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Re: Help me with my P89C51RD2BA...
« Reply #4 on: September 03, 2003, 11:41:08 am »
The 89C51RD2BA will work with Flash Magic if you add the work around in figure 2 on the Errata sheet.

It is a simple RC network that delays PSEN going low for ~ 10us.  
I actually used a 10K ohm resistor and a 10uF cap. which gave about a 1ms delay....way long than needed but it works great.

And this delay will have no effect on programming 89C51RD2HBAs.

Good Luck,

erik malund

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Re: Help me with my P89C51RD2BA...
« Reply #5 on: September 04, 2003, 06:09:59 am »
go to The first article describes a means of entering IAP for program updates WITHOUT clipwires, switches and all the other stuff.  The second article describes a means oif entering IAp with just one clipwire/switch



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Re: Help me with my P89C51RD2BA...
« Reply #6 on: September 08, 2003, 08:12:02 am »
Please try to keep PSEN low when you are using ISP.