P89C51rd2HBP

[Sunil Patil]

Hello,
I am using ISP programing for the first time. I am using the circuit given in Application note AN461_11.  It satisfies following conditions.
1)PSEN is grounded through 2k resistor.
2)EA =5v
3)P2.6 and P2.7 is high(=5v)
4)ALE is floating
My comport is working properly. Chip is working properly. I am following the instructions given in Application note 4.
It gives me following error when I tried to reset with FlashMagic program software.
"Unable to communicate(transmit/receive). Ensure that COM port is not used by any other program Please try to lower or raise the baud rate."

I have tried using each and every baud rate given. But its not serving the purpose. What could be the source(or sources ) of error?
 
Thanks,
Sunil

[Andy Ayre]

It could be many things. What crystal frequency are you using? If it is 10MHz or higher then 9600 baud should definately work.

You said you are followed application note 4. What are the results of performing the tests in section 4.1 - "Terminal Test"? That will tell me a lot.

[Sunil Patil]

Thanks for prompt reply,
Well ,

I am using 11.0592 Mhz crystal. Regarding terminal test, I am not understanding how to start BootROM feature in Hyperterminal.

But I have written simple program which tests whether RS232-Microcontroller communication works or not. And it is working.

Additional information which I would like to give is that, I have programmed this chip using parallel programmer(To program above mentioned step) Is it anyway related to my cause of the problem?

Sunil Patil

[erik malund]

"I have programmed this chip using parallel programmer(To program above mentioned step) Is it anyway related to my cause of the problem?"

It is, if the programmer changed the boot vector.

Erik

[Andy Ayre]

First check using your parallel programmer that you haven't changed the boot vector from the default, as Erik suggested.

Second, to test entering ISP mode simply connect to the device using Hyperterminal as described in the app note and send a single uppercase 'U'. It should be echoed back. If not then you need to investigate why it wasn't echoed back. The app note leads you through this. For example, did the 'U' reach the device? Was the baudrate at the RxD pin what you expected? Sometimes optocouplers can affect the baud rate for example.

If you can get the 'U' to echo back, then Flash Magic should work at the same baud rate you used in Hyperterminal. Make sure you enter an accurate crystal frequency and turn off high speed communications (and half-duplex communications if possible) to simplify the situation.

[Andy Ayre]

Note also, that if you are using a low crystal frequency such as 6MHz, then you will likely need to use a very low baud rate, such as 4800 or 2400.

[Sunil Patil]

Thanks a lot Mr. Andrew and Mr. Eric

As you said, Parallel programming changed the my Boot vector value from FC to 00. I have changed it and now it is working fine. I could program the chip elegantly. Thanks a lot for providing such a good facility.

Sunil Patil

[Tapan]

hi!!
     I am using the ISP feature for the first time. But it is not working.
     I am facing the same problems what Mr Sunil Patil is facing.
     I haven't used hyperterminal. But instead I have written a simple program in C to transmit 'U' and wait for the response from Microcontroller.
     But that doesnt work. My com port is fine and I have tested it.
     I have  used the same circuit as described in ISP application note.
     One thing i noticed which i feel is odd that when I see the voltage on /PSEN pin on Oscillscope I find that even though I have pulled down the /PSEN pin through 2K resistor it still shows voltage level of 5V.
     Has this anything to do with the problem or it is normal??
     I have not programmed it using parallel programmer. But I would like to check the BOOT VECTOR. But i dont know how to check it and if it is changed how should i modify it to FCh again
     Regards------
    Tapan Vinchhi.

[Andy Ayre]

If /PSEN still is high enough to be regarded as a logic 1 then that is probably your problem. Does it show a voltage of 5V on /PSEN while you are holding the device in Reset?

You can check and change the boot vector with Flash Magic, assuming you can connect. Choose Status Byte and Boot Vector... from the ISP menu. The current settings will be displayed.

[prabira]

Hi,

I'm trying to use the P89C51RD2HBP for the first time. But unfortunately, it's not connecting. I've tried all the tricks: changed the capacitors to 1muF, used 12-0-12 transformer and capacitor filters, changed 3/4 cables; but it's still not responding. I can't understand where the error may be. Please help !

prabira

[erikm]

<>>I've tried all the tricks: changed the capacitors to 1muF, used 12-0-12 transformer and capacitor filters, changed 3/4 cables<<

I see no mention of checking the MAX232(equivalent) and its connections

Erik

[erikm]

>>changed the capacitors to 1muF<<

Suunds like you are using RC reset, the Rx2Hs are notorious for malfunctioning without a supervisor.  If that happens only a parallel programmer can save the chip.

Erik

[MUHAMMAD KHAWAR]

 I am using MTS-51 P89C51RD2HBP training kit. Now it is not communication its interfacing program philips winisp but the program is running and kit emulator is working. I think some one has removed its communication routine program.   what do you say.

[erikm]

I am using MTS-51 P89C51RD2HBP training kit. a link would be nice, Google :
Course MTS-51

[Jan Waclawek]

Oh, Erik, Google is exactly as my son, he knows the right answer just you need to figure out how to ask... :-)
http://www.google.com/search?q=MTS-51+trainer
gives you the manufacturer. However, there is almost no information, probably unless you register as a reseller - but, honestly, do you really need more info?
I think this might be the infamous "lost boot vector" case...
Muhammad: you will probably need to get somebody with a parallel programmer to reprogram the boot vector.

Jan Waclawek