ERROR: UNABLE TO COMMUNICATE

[tnnflash]

Hi,

Use Flash Magic to program a P89V51RC2 in ISP Mode;

I have directly Connected the COM1 of the PC with the pins RX and TX of the microprocessor...

With the command READ DEVICE SIGNATURE is verified this error:

"Failed to read the device signature (Operation Failed...) Accesing to device using the wrong protocol..."  or "UNABLE TO COMMUNICATE.(in use)..."

Who can help me?

thanks

[Andy Ayre]

You can't directly connect the COM port of a PC to the RxD and TxD pins on a microcontroller. The voltages used are different and you might have damaged your device.

1. Replace your microcontroller with a new one

2. Use a MAX232 or equivalent between the COM port and microcontroller.

Andy

[tnnflash]

thanks for answer...

now all ok 

You can't directly connect the COM port of a PC to the RxD and TxD pins on a microcontroller. The voltages used are different and you might have damaged your device.

1. Replace your microcontroller with a new one

2. Use a MAX232 or equivalent between the COM port and microcontroller.

Andy