P89C51RD2BN ISP Problem

[lasa47]

Hi,

I am using one of P89C51RD2BN chip and I couldn

[Andy Ayre]

Try this:

Switch back to using manual ISP entry (buttons or jumpers for RST and PSEN)
Start Hyperterminal.
8 bits, no parity, 1 stop bit, no flow control
9600 baud
Reset the device into ISP mode
Send a single uppercase 'U'.

Is the 'U' echoed back?

If it isn't then:

Check the voltages on the RST and PSEN pins when performing ISP entry to make sure they are correct.
Use a scope to make sure the timings of RST and PSEN are within the allowed limits in the datasheet.
Use the scope to make sure the 'U' is arriving at the RxD pin.
Use the scope to see if anything is being transmitted from the TxD pin.
Use the scope to check you have sine waves at the XTAL pins.
Look for glitches or ripple on VCC, RST, etc.

If the 'U' is echoed back then let us know for next steps.

[lasa47]

Hi,

Thanks a lot. I found the error last night. It was in Max232 interface chip. The chip was totally out. I just change the chip. Every thing works fine. It was grate. 100% accurate flash programming.
I appreciate your help at all. Flash magic is a magic....Excellent.

Thanks a lot,
Lasantha

[Andy Ayre]

Thanks for posting back with the solution - it helps others in the future who run into similar problems!

[erikm]

Thanks a lot. I found the error last night. It was in Max232 interface chip. The chip was totally out.

although this is a specific FlashMagic forum, your posting of the problem and solution lead me to give you some non-FM information.

Ground is NOT alwways ground.  Many 232 transcievers have been blown due to non-optimal grounding of the PC and/or the uC board.  Be careful when hooking up the connection.  Connecting PC ground to uC ground can give really nasty power surges.

If your uC ground is conneted to power ground either remove that connection or ALWAYS connect the PC to the uC board before powering up the uC board.

Erik

[lasa47]

Hi Erik,

You are right erik. It is possible according to the theory. Thanks for your comments.

Lasantha